Пример #1
0
/*
 * Double_add: add two double precision values.
 */
dbl_fadd(
    dbl_floating_point *leftptr,
    dbl_floating_point *rightptr,
    dbl_floating_point *dstptr,
    unsigned int *status)
{
    register unsigned int signless_upper_left, signless_upper_right, save;
    register unsigned int leftp1, leftp2, rightp1, rightp2, extent;
    register unsigned int resultp1 = 0, resultp2 = 0;
    
    register int result_exponent, right_exponent, diff_exponent;
    register int sign_save, jumpsize;
    register boolean inexact = FALSE;
    register boolean underflowtrap;
        
    /* Create local copies of the numbers */
    Dbl_copyfromptr(leftptr,leftp1,leftp2);
    Dbl_copyfromptr(rightptr,rightp1,rightp2);

    /* A zero "save" helps discover equal operands (for later),  *
     * and is used in swapping operands (if needed).             */
    Dbl_xortointp1(leftp1,rightp1,/*to*/save);

    /*
     * check first operand for NaN's or infinity
     */
    if ((result_exponent = Dbl_exponent(leftp1)) == DBL_INFINITY_EXPONENT)
	{
	if (Dbl_iszero_mantissa(leftp1,leftp2)) 
	    {
	    if (Dbl_isnotnan(rightp1,rightp2)) 
		{
		if (Dbl_isinfinity(rightp1,rightp2) && save!=0) 
		    {
		    /* 
		     * invalid since operands are opposite signed infinity's
		     */
		    if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
                    Set_invalidflag();
                    Dbl_makequietnan(resultp1,resultp2);
		    Dbl_copytoptr(resultp1,resultp2,dstptr);
		    return(NOEXCEPTION);
		    }
		/*
	 	 * return infinity
	 	 */
		Dbl_copytoptr(leftp1,leftp2,dstptr);
		return(NOEXCEPTION);
		}
	    }
	else 
	    {
            /*
             * is NaN; signaling or quiet?
             */
            if (Dbl_isone_signaling(leftp1)) 
		{
               	/* trap if INVALIDTRAP enabled */
		if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
        	/* make NaN quiet */
        	Set_invalidflag();
        	Dbl_set_quiet(leftp1);
        	}
	    /* 
	     * is second operand a signaling NaN? 
	     */
	    else if (Dbl_is_signalingnan(rightp1)) 
		{
        	/* trap if INVALIDTRAP enabled */
               	if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
		/* make NaN quiet */
		Set_invalidflag();
		Dbl_set_quiet(rightp1);
		Dbl_copytoptr(rightp1,rightp2,dstptr);
		return(NOEXCEPTION);
		}
	    /*
 	     * return quiet NaN
 	     */
	    Dbl_copytoptr(leftp1,leftp2,dstptr);
 	    return(NOEXCEPTION);
	    }
	} /* End left NaN or Infinity processing */
    /*
     * check second operand for NaN's or infinity
     */
    if (Dbl_isinfinity_exponent(rightp1)) 
	{
	if (Dbl_iszero_mantissa(rightp1,rightp2)) 
	    {
	    /* return infinity */
	    Dbl_copytoptr(rightp1,rightp2,dstptr);
	    return(NOEXCEPTION);
	    }
        /*
         * is NaN; signaling or quiet?
         */
        if (Dbl_isone_signaling(rightp1)) 
	    {
            /* trap if INVALIDTRAP enabled */
	    if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
	    /* make NaN quiet */
	    Set_invalidflag();
	    Dbl_set_quiet(rightp1);
	    }
	/*
	 * return quiet NaN
 	 */
	Dbl_copytoptr(rightp1,rightp2,dstptr);
	return(NOEXCEPTION);
    	} /* End right NaN or Infinity processing */

    /* Invariant: Must be dealing with finite numbers */

    /* Compare operands by removing the sign */
    Dbl_copytoint_exponentmantissap1(leftp1,signless_upper_left);
    Dbl_copytoint_exponentmantissap1(rightp1,signless_upper_right);

    /* sign difference selects add or sub operation. */
    if(Dbl_ismagnitudeless(leftp2,rightp2,signless_upper_left,signless_upper_right))
	{
	/* Set the left operand to the larger one by XOR swap *
	 *  First finish the first word using "save"          */
	Dbl_xorfromintp1(save,rightp1,/*to*/rightp1);
	Dbl_xorfromintp1(save,leftp1,/*to*/leftp1);
     	Dbl_swap_lower(leftp2,rightp2);
	result_exponent = Dbl_exponent(leftp1);
	}
    /* Invariant:  left is not smaller than right. */ 

    if((right_exponent = Dbl_exponent(rightp1)) == 0)
        {
	/* Denormalized operands.  First look for zeroes */
	if(Dbl_iszero_mantissa(rightp1,rightp2)) 
	    {
	    /* right is zero */
	    if(Dbl_iszero_exponentmantissa(leftp1,leftp2))
		{
		/* Both operands are zeros */
		if(Is_rounding_mode(ROUNDMINUS))
		    {
		    Dbl_or_signs(leftp1,/*with*/rightp1);
		    }
		else
		    {
		    Dbl_and_signs(leftp1,/*with*/rightp1);
		    }
		}
	    else 
		{
		/* Left is not a zero and must be the result.  Trapped
		 * underflows are signaled if left is denormalized.  Result
		 * is always exact. */
		if( (result_exponent == 0) && Is_underflowtrap_enabled() )
		    {
		    /* need to normalize results mantissa */
	    	    sign_save = Dbl_signextendedsign(leftp1);
		    Dbl_leftshiftby1(leftp1,leftp2);
		    Dbl_normalize(leftp1,leftp2,result_exponent);
		    Dbl_set_sign(leftp1,/*using*/sign_save);
                    Dbl_setwrapped_exponent(leftp1,result_exponent,unfl);
		    Dbl_copytoptr(leftp1,leftp2,dstptr);
		    /* inexact = FALSE */
		    return(UNDERFLOWEXCEPTION);
		    }
		}
	    Dbl_copytoptr(leftp1,leftp2,dstptr);
	    return(NOEXCEPTION);
	    }

	/* Neither are zeroes */
	Dbl_clear_sign(rightp1);	/* Exponent is already cleared */
	if(result_exponent == 0 )
	    {
	    /* Both operands are denormalized.  The result must be exact
	     * and is simply calculated.  A sum could become normalized and a
	     * difference could cancel to a true zero. */
	    if( (/*signed*/int) save < 0 )
		{
		Dbl_subtract(leftp1,leftp2,/*minus*/rightp1,rightp2,
		/*into*/resultp1,resultp2);
		if(Dbl_iszero_mantissa(resultp1,resultp2))
		    {
		    if(Is_rounding_mode(ROUNDMINUS))
			{
			Dbl_setone_sign(resultp1);
			}
		    else
			{
			Dbl_setzero_sign(resultp1);
			}
		    Dbl_copytoptr(resultp1,resultp2,dstptr);
		    return(NOEXCEPTION);
		    }
		}
	    else
		{
		Dbl_addition(leftp1,leftp2,rightp1,rightp2,
		/*into*/resultp1,resultp2);
		if(Dbl_isone_hidden(resultp1))
		    {
		    Dbl_copytoptr(resultp1,resultp2,dstptr);
		    return(NOEXCEPTION);
		    }
		}
	    if(Is_underflowtrap_enabled())
		{
		/* need to normalize result */
	    	sign_save = Dbl_signextendedsign(resultp1);
		Dbl_leftshiftby1(resultp1,resultp2);
		Dbl_normalize(resultp1,resultp2,result_exponent);
		Dbl_set_sign(resultp1,/*using*/sign_save);
                Dbl_setwrapped_exponent(resultp1,result_exponent,unfl);
	        Dbl_copytoptr(resultp1,resultp2,dstptr);
		/* inexact = FALSE */
	        return(UNDERFLOWEXCEPTION);
		}
	    Dbl_copytoptr(resultp1,resultp2,dstptr);
	    return(NOEXCEPTION);
	    }
	right_exponent = 1;	/* Set exponent to reflect different bias
				 * with denomalized numbers. */
	}
    else
	{
	Dbl_clear_signexponent_set_hidden(rightp1);
	}
    Dbl_clear_exponent_set_hidden(leftp1);
    diff_exponent = result_exponent - right_exponent;

    /* 
     * Special case alignment of operands that would force alignment 
     * beyond the extent of the extension.  A further optimization
     * could special case this but only reduces the path length for this
     * infrequent case.
     */
    if(diff_exponent > DBL_THRESHOLD)
	{
	diff_exponent = DBL_THRESHOLD;
	}
    
    /* Align right operand by shifting to right */
    Dbl_right_align(/*operand*/rightp1,rightp2,/*shifted by*/diff_exponent,
    /*and lower to*/extent);

    /* Treat sum and difference of the operands separately. */
    if( (/*signed*/int) save < 0 )
	{
	/*
	 * Difference of the two operands.  Their can be no overflow.  A
	 * borrow can occur out of the hidden bit and force a post
	 * normalization phase.
	 */
	Dbl_subtract_withextension(leftp1,leftp2,/*minus*/rightp1,rightp2,
	/*with*/extent,/*into*/resultp1,resultp2);
	if(Dbl_iszero_hidden(resultp1))
	    {
	    /* Handle normalization */
	    /* A straight forward algorithm would now shift the result
	     * and extension left until the hidden bit becomes one.  Not
	     * all of the extension bits need participate in the shift.
	     * Only the two most significant bits (round and guard) are
	     * needed.  If only a single shift is needed then the guard
	     * bit becomes a significant low order bit and the extension
	     * must participate in the rounding.  If more than a single 
	     * shift is needed, then all bits to the right of the guard 
	     * bit are zeros, and the guard bit may or may not be zero. */
	    sign_save = Dbl_signextendedsign(resultp1);
            Dbl_leftshiftby1_withextent(resultp1,resultp2,extent,resultp1,resultp2);

            /* Need to check for a zero result.  The sign and exponent
	     * fields have already been zeroed.  The more efficient test
	     * of the full object can be used.
	     */
    	    if(Dbl_iszero(resultp1,resultp2))
		/* Must have been "x-x" or "x+(-x)". */
		{
		if(Is_rounding_mode(ROUNDMINUS)) Dbl_setone_sign(resultp1);
		Dbl_copytoptr(resultp1,resultp2,dstptr);
		return(NOEXCEPTION);
		}
	    result_exponent--;
	    /* Look to see if normalization is finished. */
	    if(Dbl_isone_hidden(resultp1))
		{
		if(result_exponent==0)
		    {
		    /* Denormalized, exponent should be zero.  Left operand *
		     * was normalized, so extent (guard, round) was zero    */
		    goto underflow;
		    }
		else
		    {
		    /* No further normalization is needed. */
		    Dbl_set_sign(resultp1,/*using*/sign_save);
	    	    Ext_leftshiftby1(extent);
		    goto round;
		    }
		}

	    /* Check for denormalized, exponent should be zero.  Left    *
	     * operand was normalized, so extent (guard, round) was zero */
	    if(!(underflowtrap = Is_underflowtrap_enabled()) &&
	       result_exponent==0) goto underflow;

	    /* Shift extension to complete one bit of normalization and
	     * update exponent. */
	    Ext_leftshiftby1(extent);

	    /* Discover first one bit to determine shift amount.  Use a
	     * modified binary search.  We have already shifted the result
	     * one position right and still not found a one so the remainder
	     * of the extension must be zero and simplifies rounding. */
	    /* Scan bytes */
	    while(Dbl_iszero_hiddenhigh7mantissa(resultp1))
		{
		Dbl_leftshiftby8(resultp1,resultp2);
		if((result_exponent -= 8) <= 0  && !underflowtrap)
		    goto underflow;
		}
	    /* Now narrow it down to the nibble */
	    if(Dbl_iszero_hiddenhigh3mantissa(resultp1))
		{
		/* The lower nibble contains the normalizing one */
		Dbl_leftshiftby4(resultp1,resultp2);
		if((result_exponent -= 4) <= 0 && !underflowtrap)
		    goto underflow;
		}
	    /* Select case were first bit is set (already normalized)
	     * otherwise select the proper shift. */
	    if((jumpsize = Dbl_hiddenhigh3mantissa(resultp1)) > 7)
		{
		/* Already normalized */
		if(result_exponent <= 0) goto underflow;
		Dbl_set_sign(resultp1,/*using*/sign_save);
		Dbl_set_exponent(resultp1,/*using*/result_exponent);
		Dbl_copytoptr(resultp1,resultp2,dstptr);
		return(NOEXCEPTION);
		}
	    Dbl_sethigh4bits(resultp1,/*using*/sign_save);
	    switch(jumpsize) 
		{
		case 1:
		    {
		    Dbl_leftshiftby3(resultp1,resultp2);
		    result_exponent -= 3;
		    break;
		    }
		case 2:
		case 3:
		    {
		    Dbl_leftshiftby2(resultp1,resultp2);
		    result_exponent -= 2;
		    break;
		    }
		case 4:
		case 5:
		case 6:
		case 7:
		    {
		    Dbl_leftshiftby1(resultp1,resultp2);
		    result_exponent -= 1;
		    break;
		    }
		}
	    if(result_exponent > 0) 
		{
		Dbl_set_exponent(resultp1,/*using*/result_exponent);
		Dbl_copytoptr(resultp1,resultp2,dstptr);
		return(NOEXCEPTION); 	/* Sign bit is already set */
		}
	    /* Fixup potential underflows */
	  underflow:
	    if(Is_underflowtrap_enabled())
		{
		Dbl_set_sign(resultp1,sign_save);
                Dbl_setwrapped_exponent(resultp1,result_exponent,unfl);
		Dbl_copytoptr(resultp1,resultp2,dstptr);
		/* inexact = FALSE */
		return(UNDERFLOWEXCEPTION);
		}
	    /* 
	     * Since we cannot get an inexact denormalized result,
	     * we can now return.
	     */
	    Dbl_fix_overshift(resultp1,resultp2,(1-result_exponent),extent);
	    Dbl_clear_signexponent(resultp1);
	    Dbl_set_sign(resultp1,sign_save);
	    Dbl_copytoptr(resultp1,resultp2,dstptr);
	    return(NOEXCEPTION);
	    } /* end if(hidden...)... */
	/* Fall through and round */
	} /* end if(save < 0)... */
    else 
	{
	/* Add magnitudes */
	Dbl_addition(leftp1,leftp2,rightp1,rightp2,/*to*/resultp1,resultp2);
	if(Dbl_isone_hiddenoverflow(resultp1))
	    {
	    /* Prenormalization required. */
	    Dbl_rightshiftby1_withextent(resultp2,extent,extent);
	    Dbl_arithrightshiftby1(resultp1,resultp2);
	    result_exponent++;
	    } /* end if hiddenoverflow... */
	} /* end else ...add magnitudes... */
    
    /* Round the result.  If the extension is all zeros,then the result is
     * exact.  Otherwise round in the correct direction.  No underflow is
     * possible. If a postnormalization is necessary, then the mantissa is
     * all zeros so no shift is needed. */
  round:
    if(Ext_isnotzero(extent))
	{
	inexact = TRUE;
	switch(Rounding_mode())
	    {
	    case ROUNDNEAREST: /* The default. */
	    if(Ext_isone_sign(extent))
		{
		/* at least 1/2 ulp */
		if(Ext_isnotzero_lower(extent)  ||
		  Dbl_isone_lowmantissap2(resultp2))
		    {
		    /* either exactly half way and odd or more than 1/2ulp */
		    Dbl_increment(resultp1,resultp2);
		    }
		}
	    break;

	    case ROUNDPLUS:
	    if(Dbl_iszero_sign(resultp1))
		{
		/* Round up positive results */
		Dbl_increment(resultp1,resultp2);
		}
	    break;
	    
	    case ROUNDMINUS:
	    if(Dbl_isone_sign(resultp1))
		{
		/* Round down negative results */
		Dbl_increment(resultp1,resultp2);
		}
	    
	    case ROUNDZERO:;
	    /* truncate is simple */
	    } /* end switch... */
	if(Dbl_isone_hiddenoverflow(resultp1)) result_exponent++;
	}
    if(result_exponent == DBL_INFINITY_EXPONENT)
        {
        /* Overflow */
        if(Is_overflowtrap_enabled())
	    {
	    Dbl_setwrapped_exponent(resultp1,result_exponent,ovfl);
	    Dbl_copytoptr(resultp1,resultp2,dstptr);
	    if (inexact)
		if (Is_inexacttrap_enabled())
			return(OVERFLOWEXCEPTION | INEXACTEXCEPTION);
		else Set_inexactflag();
	    return(OVERFLOWEXCEPTION);
	    }
        else
	    {
	    inexact = TRUE;
	    Set_overflowflag();
	    Dbl_setoverflow(resultp1,resultp2);
	    }
	}
    else Dbl_set_exponent(resultp1,result_exponent);
    Dbl_copytoptr(resultp1,resultp2,dstptr);
    if(inexact) 
	if(Is_inexacttrap_enabled())
	    return(INEXACTEXCEPTION);
	else Set_inexactflag();
    return(NOEXCEPTION);
}
Пример #2
0
/*ARGSUSED*/
int
dbl_fsqrt(dbl_floating_point *srcptr, dbl_floating_point *dstptr,
    unsigned int *status)
{
	register unsigned int srcp1, srcp2, resultp1, resultp2;
	register unsigned int newbitp1, newbitp2, sump1, sump2;
	register int src_exponent;
	register int guardbit = false, even_exponent;

	Dbl_copyfromptr(srcptr,srcp1,srcp2);
	/*
	 * check source operand for NaN or infinity
	 */
	if ((src_exponent = Dbl_exponent(srcp1)) == DBL_INFINITY_EXPONENT) {
		/*
		 * is signaling NaN?
		 */
		if (Dbl_isone_signaling(srcp1)) {
			/* trap if INVALIDTRAP enabled */
			if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
			/* make NaN quiet */
			Set_invalidflag();
			Dbl_set_quiet(srcp1);
		}
		/*
		 * Return quiet NaN or positive infinity.
		 *  Fall thru to negative test if negative infinity.
		 */
		if (Dbl_iszero_sign(srcp1) ||
		    Dbl_isnotzero_mantissa(srcp1,srcp2)) {
			Dbl_copytoptr(srcp1,srcp2,dstptr);
			return(NOEXCEPTION);
		}
	}

	/*
	 * check for zero source operand
	 */
	if (Dbl_iszero_exponentmantissa(srcp1,srcp2)) {
		Dbl_copytoptr(srcp1,srcp2,dstptr);
		return(NOEXCEPTION);
	}

	/*
	 * check for negative source operand
	 */
	if (Dbl_isone_sign(srcp1)) {
		/* trap if INVALIDTRAP enabled */
		if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
		/* make NaN quiet */
		Set_invalidflag();
		Dbl_makequietnan(srcp1,srcp2);
		Dbl_copytoptr(srcp1,srcp2,dstptr);
		return(NOEXCEPTION);
	}

	/*
	 * Generate result
	 */
	if (src_exponent > 0) {
		even_exponent = Dbl_hidden(srcp1);
		Dbl_clear_signexponent_set_hidden(srcp1);
	}
	else {
		/* normalize operand */
		Dbl_clear_signexponent(srcp1);
		src_exponent++;
		Dbl_normalize(srcp1,srcp2,src_exponent);
		even_exponent = src_exponent & 1;
	}
	if (even_exponent) {
		/* exponent is even */
		/* Add comment here.  Explain why odd exponent needs correction */
		Dbl_leftshiftby1(srcp1,srcp2);
	}
	/*
	 * Add comment here.  Explain following algorithm.
	 *
	 * Trust me, it works.
	 *
	 */
	Dbl_setzero(resultp1,resultp2);
	Dbl_allp1(newbitp1) = 1 << (DBL_P - 32);
	Dbl_setzero_mantissap2(newbitp2);
	while (Dbl_isnotzero(newbitp1,newbitp2) && Dbl_isnotzero(srcp1,srcp2)) {
		Dbl_addition(resultp1,resultp2,newbitp1,newbitp2,sump1,sump2);
		if(Dbl_isnotgreaterthan(sump1,sump2,srcp1,srcp2)) {
			Dbl_leftshiftby1(newbitp1,newbitp2);
			/* update result */
			Dbl_addition(resultp1,resultp2,newbitp1,newbitp2,
			 resultp1,resultp2);
			Dbl_subtract(srcp1,srcp2,sump1,sump2,srcp1,srcp2);
			Dbl_rightshiftby2(newbitp1,newbitp2);
		}
		else {
			Dbl_rightshiftby1(newbitp1,newbitp2);
		}
		Dbl_leftshiftby1(srcp1,srcp2);
	}
	/* correct exponent for pre-shift */
	if (even_exponent) {
		Dbl_rightshiftby1(resultp1,resultp2);
	}

	/* check for inexact */
	if (Dbl_isnotzero(srcp1,srcp2)) {
		if (!even_exponent && Dbl_islessthan(resultp1,resultp2,srcp1,srcp2)) {
			Dbl_increment(resultp1,resultp2);
		}
		guardbit = Dbl_lowmantissap2(resultp2);
		Dbl_rightshiftby1(resultp1,resultp2);

		/*  now round result  */
		switch (Rounding_mode()) {
		case ROUNDPLUS:
		     Dbl_increment(resultp1,resultp2);
		     break;
		case ROUNDNEAREST:
		     /* stickybit is always true, so guardbit
		      * is enough to determine rounding */
		     if (guardbit) {
			    Dbl_increment(resultp1,resultp2);
		     }
		     break;
		}
		/* increment result exponent by 1 if mantissa overflowed */
		if (Dbl_isone_hiddenoverflow(resultp1)) src_exponent+=2;

		if (Is_inexacttrap_enabled()) {
			Dbl_set_exponent(resultp1,
			 ((src_exponent-DBL_BIAS)>>1)+DBL_BIAS);
			Dbl_copytoptr(resultp1,resultp2,dstptr);
			return(INEXACTEXCEPTION);
		}
		else Set_inexactflag();
	}
Пример #3
0
int
sgl_fmpy(
    sgl_floating_point *srcptr1,
    sgl_floating_point *srcptr2,
    sgl_floating_point *dstptr,
    unsigned int *status)
{
    register unsigned int opnd1, opnd2, opnd3, result;
    register int dest_exponent, count;
    register boolean inexact = FALSE, guardbit = FALSE, stickybit = FALSE;
    boolean is_tiny;

    opnd1 = *srcptr1;
    opnd2 = *srcptr2;
    /*
     * set sign bit of result
     */
    if (Sgl_sign(opnd1) ^ Sgl_sign(opnd2)) Sgl_setnegativezero(result);
    else Sgl_setzero(result);
    /*
     * check first operand for NaN's or infinity
     */
    if (Sgl_isinfinity_exponent(opnd1)) {
        if (Sgl_iszero_mantissa(opnd1)) {
            if (Sgl_isnotnan(opnd2)) {
                if (Sgl_iszero_exponentmantissa(opnd2)) {
                    /*
                     * invalid since operands are infinity
                     * and zero
                     */
                    if (Is_invalidtrap_enabled())
                        return(INVALIDEXCEPTION);
                    Set_invalidflag();
                    Sgl_makequietnan(result);
                    *dstptr = result;
                    return(NOEXCEPTION);
                }
                /*
                 * return infinity
                 */
                Sgl_setinfinity_exponentmantissa(result);
                *dstptr = result;
                return(NOEXCEPTION);
            }
        }
        else {
            /*
             * is NaN; signaling or quiet?
             */
            if (Sgl_isone_signaling(opnd1)) {
                /* trap if INVALIDTRAP enabled */
                if (Is_invalidtrap_enabled())
                    return(INVALIDEXCEPTION);
                /* make NaN quiet */
                Set_invalidflag();
                Sgl_set_quiet(opnd1);
            }
            /*
             * is second operand a signaling NaN?
             */
            else if (Sgl_is_signalingnan(opnd2)) {
                /* trap if INVALIDTRAP enabled */
                if (Is_invalidtrap_enabled())
                    return(INVALIDEXCEPTION);
                /* make NaN quiet */
                Set_invalidflag();
                Sgl_set_quiet(opnd2);
                *dstptr = opnd2;
                return(NOEXCEPTION);
            }
            /*
             * return quiet NaN
             */
            *dstptr = opnd1;
            return(NOEXCEPTION);
        }
    }
    /*
     * check second operand for NaN's or infinity
     */
    if (Sgl_isinfinity_exponent(opnd2)) {
        if (Sgl_iszero_mantissa(opnd2)) {
            if (Sgl_iszero_exponentmantissa(opnd1)) {
                /* invalid since operands are zero & infinity */
                if (Is_invalidtrap_enabled())
                    return(INVALIDEXCEPTION);
                Set_invalidflag();
                Sgl_makequietnan(opnd2);
                *dstptr = opnd2;
                return(NOEXCEPTION);
            }
            /*
             * return infinity
             */
            Sgl_setinfinity_exponentmantissa(result);
            *dstptr = result;
            return(NOEXCEPTION);
        }
        /*
         * is NaN; signaling or quiet?
         */
        if (Sgl_isone_signaling(opnd2)) {
            /* trap if INVALIDTRAP enabled */
            if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);

            /* make NaN quiet */
            Set_invalidflag();
            Sgl_set_quiet(opnd2);
        }
        /*
         * return quiet NaN
         */
        *dstptr = opnd2;
        return(NOEXCEPTION);
    }
    /*
     * Generate exponent
     */
    dest_exponent = Sgl_exponent(opnd1) + Sgl_exponent(opnd2) - SGL_BIAS;

    /*
     * Generate mantissa
     */
    if (Sgl_isnotzero_exponent(opnd1)) {
        /* set hidden bit */
        Sgl_clear_signexponent_set_hidden(opnd1);
    }
    else {
        /* check for zero */
        if (Sgl_iszero_mantissa(opnd1)) {
            Sgl_setzero_exponentmantissa(result);
            *dstptr = result;
            return(NOEXCEPTION);
        }
        /* is denormalized, adjust exponent */
        Sgl_clear_signexponent(opnd1);
        Sgl_leftshiftby1(opnd1);
        Sgl_normalize(opnd1,dest_exponent);
    }
    /* opnd2 needs to have hidden bit set with msb in hidden bit */
    if (Sgl_isnotzero_exponent(opnd2)) {
        Sgl_clear_signexponent_set_hidden(opnd2);
    }
    else {
        /* check for zero */
        if (Sgl_iszero_mantissa(opnd2)) {
            Sgl_setzero_exponentmantissa(result);
            *dstptr = result;
            return(NOEXCEPTION);
        }
        /* is denormalized; want to normalize */
        Sgl_clear_signexponent(opnd2);
        Sgl_leftshiftby1(opnd2);
        Sgl_normalize(opnd2,dest_exponent);
    }

    /* Multiply two source mantissas together */

    Sgl_leftshiftby4(opnd2);     /* make room for guard bits */
    Sgl_setzero(opnd3);
    /*
     * Four bits at a time are inspected in each loop, and a
     * simple shift and add multiply algorithm is used.
     */
    for (count=1; count<SGL_P; count+=4) {
        stickybit |= Slow4(opnd3);
        Sgl_rightshiftby4(opnd3);
        if (Sbit28(opnd1)) Sall(opnd3) += (Sall(opnd2) << 3);
        if (Sbit29(opnd1)) Sall(opnd3) += (Sall(opnd2) << 2);
        if (Sbit30(opnd1)) Sall(opnd3) += (Sall(opnd2) << 1);
        if (Sbit31(opnd1)) Sall(opnd3) += Sall(opnd2);
        Sgl_rightshiftby4(opnd1);
    }
    /* make sure result is left-justified */
    if (Sgl_iszero_sign(opnd3)) {
        Sgl_leftshiftby1(opnd3);
    }
    else {
        /* result mantissa >= 2. */
        dest_exponent++;
    }
    /* check for denormalized result */
    while (Sgl_iszero_sign(opnd3)) {
        Sgl_leftshiftby1(opnd3);
        dest_exponent--;
    }
    /*
     * check for guard, sticky and inexact bits
     */
    stickybit |= Sgl_all(opnd3) << (SGL_BITLENGTH - SGL_EXP_LENGTH + 1);
    guardbit = Sbit24(opnd3);
    inexact = guardbit | stickybit;

    /* re-align mantissa */
    Sgl_rightshiftby8(opnd3);

    /*
     * round result
     */
    if (inexact && (dest_exponent>0 || Is_underflowtrap_enabled())) {
        Sgl_clear_signexponent(opnd3);
        switch (Rounding_mode()) {
        case ROUNDPLUS:
            if (Sgl_iszero_sign(result))
                Sgl_increment(opnd3);
            break;
        case ROUNDMINUS:
            if (Sgl_isone_sign(result))
                Sgl_increment(opnd3);
            break;
        case ROUNDNEAREST:
            if (guardbit) {
                if (stickybit || Sgl_isone_lowmantissa(opnd3))
                    Sgl_increment(opnd3);
            }
        }
        if (Sgl_isone_hidden(opnd3)) dest_exponent++;
    }
    Sgl_set_mantissa(result,opnd3);

    /*
     * Test for overflow
     */
    if (dest_exponent >= SGL_INFINITY_EXPONENT) {
        /* trap if OVERFLOWTRAP enabled */
        if (Is_overflowtrap_enabled()) {
            /*
             * Adjust bias of result
             */
            Sgl_setwrapped_exponent(result,dest_exponent,ovfl);
            *dstptr = result;
            if (inexact)
                if (Is_inexacttrap_enabled())
                    return(OVERFLOWEXCEPTION | INEXACTEXCEPTION);
                else Set_inexactflag();
            return(OVERFLOWEXCEPTION);
        }
        inexact = TRUE;
        Set_overflowflag();
        /* set result to infinity or largest number */
        Sgl_setoverflow(result);
    }
    /*
     * Test for underflow
     */
    else if (dest_exponent <= 0) {
        /* trap if UNDERFLOWTRAP enabled */
        if (Is_underflowtrap_enabled()) {
            /*
             * Adjust bias of result
             */
            Sgl_setwrapped_exponent(result,dest_exponent,unfl);
            *dstptr = result;
            if (inexact)
                if (Is_inexacttrap_enabled())
                    return(UNDERFLOWEXCEPTION | INEXACTEXCEPTION);
                else Set_inexactflag();
            return(UNDERFLOWEXCEPTION);
        }

        /* Determine if should set underflow flag */
        is_tiny = TRUE;
        if (dest_exponent == 0 && inexact) {
            switch (Rounding_mode()) {
            case ROUNDPLUS:
                if (Sgl_iszero_sign(result)) {
                    Sgl_increment(opnd3);
                    if (Sgl_isone_hiddenoverflow(opnd3))
                        is_tiny = FALSE;
                    Sgl_decrement(opnd3);
                }
                break;
            case ROUNDMINUS:
                if (Sgl_isone_sign(result)) {
                    Sgl_increment(opnd3);
                    if (Sgl_isone_hiddenoverflow(opnd3))
                        is_tiny = FALSE;
                    Sgl_decrement(opnd3);
                }
                break;
            case ROUNDNEAREST:
                if (guardbit && (stickybit ||
                                 Sgl_isone_lowmantissa(opnd3))) {
                    Sgl_increment(opnd3);
                    if (Sgl_isone_hiddenoverflow(opnd3))
                        is_tiny = FALSE;
                    Sgl_decrement(opnd3);
                }
                break;
            }
        }

        /*
         * denormalize result or set to signed zero
         */
        stickybit = inexact;
        Sgl_denormalize(opnd3,dest_exponent,guardbit,stickybit,inexact);

        /* return zero or smallest number */
        if (inexact) {
            switch (Rounding_mode()) {
            case ROUNDPLUS:
                if (Sgl_iszero_sign(result)) {
                    Sgl_increment(opnd3);
                }
                break;
            case ROUNDMINUS:
                if (Sgl_isone_sign(result)) {
                    Sgl_increment(opnd3);
                }
                break;
            case ROUNDNEAREST:
                if (guardbit && (stickybit ||
                                 Sgl_isone_lowmantissa(opnd3))) {
                    Sgl_increment(opnd3);
                }
                break;
            }
            if (is_tiny) Set_underflowflag();
        }
        Sgl_set_exponentmantissa(result,opnd3);
    }
    else Sgl_set_exponent(result,dest_exponent);
    *dstptr = result;

    /* check for inexact */
    if (inexact) {
        if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
        else Set_inexactflag();
    }
    return(NOEXCEPTION);
}
int
dbl_fdiv (dbl_floating_point * srcptr1, dbl_floating_point * srcptr2,
	  dbl_floating_point * dstptr, unsigned int *status)
{
	register unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2;
	register unsigned int opnd3p1, opnd3p2, resultp1, resultp2;
	register int dest_exponent, count;
	register boolean inexact = FALSE, guardbit = FALSE, stickybit = FALSE;
	boolean is_tiny;

	Dbl_copyfromptr(srcptr1,opnd1p1,opnd1p2);
	Dbl_copyfromptr(srcptr2,opnd2p1,opnd2p2);
	/*
	 * set sign bit of result
	 */
	if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1))
		Dbl_setnegativezerop1(resultp1);
	else Dbl_setzerop1(resultp1);
	/*
	 * check first operand for NaN's or infinity
	 */
	if (Dbl_isinfinity_exponent(opnd1p1)) {
		if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
			if (Dbl_isnotnan(opnd2p1,opnd2p2)) {
				if (Dbl_isinfinity(opnd2p1,opnd2p2)) {
					/*
					 * invalid since both operands
					 * are infinity
					 */
					if (Is_invalidtrap_enabled())
						return(INVALIDEXCEPTION);
					Set_invalidflag();
					Dbl_makequietnan(resultp1,resultp2);
					Dbl_copytoptr(resultp1,resultp2,dstptr);
					return(NOEXCEPTION);
				}
				/*
				 * return infinity
				 */
				Dbl_setinfinity_exponentmantissa(resultp1,resultp2);
				Dbl_copytoptr(resultp1,resultp2,dstptr);
				return(NOEXCEPTION);
			}
		}
		else {
			/*
			 * is NaN; signaling or quiet?
			 */
			if (Dbl_isone_signaling(opnd1p1)) {
				/* trap if INVALIDTRAP enabled */
				if (Is_invalidtrap_enabled())
					return(INVALIDEXCEPTION);
				/* make NaN quiet */
				Set_invalidflag();
				Dbl_set_quiet(opnd1p1);
			}
			/*
			 * is second operand a signaling NaN?
			 */
			else if (Dbl_is_signalingnan(opnd2p1)) {
				/* trap if INVALIDTRAP enabled */
				if (Is_invalidtrap_enabled())
					return(INVALIDEXCEPTION);
				/* make NaN quiet */
				Set_invalidflag();
				Dbl_set_quiet(opnd2p1);
				Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
				return(NOEXCEPTION);
			}
			/*
			 * return quiet NaN
			 */
			Dbl_copytoptr(opnd1p1,opnd1p2,dstptr);
			return(NOEXCEPTION);
		}
	}
	/*
	 * check second operand for NaN's or infinity
	 */
	if (Dbl_isinfinity_exponent(opnd2p1)) {
		if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) {
			/*
			 * return zero
			 */
			Dbl_setzero_exponentmantissa(resultp1,resultp2);
			Dbl_copytoptr(resultp1,resultp2,dstptr);
			return(NOEXCEPTION);
		}
                /*
                 * is NaN; signaling or quiet?
                 */
                if (Dbl_isone_signaling(opnd2p1)) {
                        /* trap if INVALIDTRAP enabled */
                        if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
                        /* make NaN quiet */
                        Set_invalidflag();
                        Dbl_set_quiet(opnd2p1);
                }
                /*
                 * return quiet NaN
                 */
		Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
                return(NOEXCEPTION);
	}
        /*
         * check for division by zero
         */
        if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) {
                if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) {
                        /* invalid since both operands are zero */
                        if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
                        Set_invalidflag();
                        Dbl_makequietnan(resultp1,resultp2);
                        Dbl_copytoptr(resultp1,resultp2,dstptr);
                        return(NOEXCEPTION);
                }
                if (Is_divisionbyzerotrap_enabled())
			return(DIVISIONBYZEROEXCEPTION);
                Set_divisionbyzeroflag();
                Dbl_setinfinity_exponentmantissa(resultp1,resultp2);
                Dbl_copytoptr(resultp1,resultp2,dstptr);
                return(NOEXCEPTION);
        }
	/*
	 * Generate exponent
	 */
	dest_exponent = Dbl_exponent(opnd1p1) - Dbl_exponent(opnd2p1) + DBL_BIAS;

	/*
	 * Generate mantissa
	 */
	if (Dbl_isnotzero_exponent(opnd1p1)) {
		/* set hidden bit */
		Dbl_clear_signexponent_set_hidden(opnd1p1);
	}
	else {
		/* check for zero */
		if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
			Dbl_setzero_exponentmantissa(resultp1,resultp2);
			Dbl_copytoptr(resultp1,resultp2,dstptr);
			return(NOEXCEPTION);
		}
                /* is denormalized, want to normalize */
                Dbl_clear_signexponent(opnd1p1);
                Dbl_leftshiftby1(opnd1p1,opnd1p2);
		Dbl_normalize(opnd1p1,opnd1p2,dest_exponent);
	}
	/* opnd2 needs to have hidden bit set with msb in hidden bit */
	if (Dbl_isnotzero_exponent(opnd2p1)) {
		Dbl_clear_signexponent_set_hidden(opnd2p1);
	}
	else {
                /* is denormalized; want to normalize */
                Dbl_clear_signexponent(opnd2p1);
                Dbl_leftshiftby1(opnd2p1,opnd2p2);
                while (Dbl_iszero_hiddenhigh7mantissa(opnd2p1)) {
                        dest_exponent+=8;
                        Dbl_leftshiftby8(opnd2p1,opnd2p2);
                }
                if (Dbl_iszero_hiddenhigh3mantissa(opnd2p1)) {
                        dest_exponent+=4;
                        Dbl_leftshiftby4(opnd2p1,opnd2p2);
                }
                while (Dbl_iszero_hidden(opnd2p1)) {
                        dest_exponent++;
                        Dbl_leftshiftby1(opnd2p1,opnd2p2);
                }
	}

	/* Divide the source mantissas */

	/*
	 * A non-restoring divide algorithm is used.
	 */
	Twoword_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2);
	Dbl_setzero(opnd3p1,opnd3p2);
	for (count=1; count <= DBL_P && (opnd1p1 || opnd1p2); count++) {
		Dbl_leftshiftby1(opnd1p1,opnd1p2);
		Dbl_leftshiftby1(opnd3p1,opnd3p2);
		if (Dbl_iszero_sign(opnd1p1)) {
			Dbl_setone_lowmantissap2(opnd3p2);
			Twoword_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2);
		}
		else {
			Twoword_add(opnd1p1, opnd1p2, opnd2p1, opnd2p2);
		}
	}
	if (count <= DBL_P) {
		Dbl_leftshiftby1(opnd3p1,opnd3p2);
		Dbl_setone_lowmantissap2(opnd3p2);
		Dbl_leftshift(opnd3p1,opnd3p2,(DBL_P-count));
		if (Dbl_iszero_hidden(opnd3p1)) {
			Dbl_leftshiftby1(opnd3p1,opnd3p2);
			dest_exponent--;
		}
	}
	else {
		if (Dbl_iszero_hidden(opnd3p1)) {
			/* need to get one more bit of result */
			Dbl_leftshiftby1(opnd1p1,opnd1p2);
			Dbl_leftshiftby1(opnd3p1,opnd3p2);
			if (Dbl_iszero_sign(opnd1p1)) {
				Dbl_setone_lowmantissap2(opnd3p2);
				Twoword_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2);
			}
			else {
				Twoword_add(opnd1p1,opnd1p2,opnd2p1,opnd2p2);
			}
			dest_exponent--;
		}
		if (Dbl_iszero_sign(opnd1p1)) guardbit = TRUE;
		stickybit = Dbl_allp1(opnd1p1) || Dbl_allp2(opnd1p2);
	}
	inexact = guardbit | stickybit;

	/*
	 * round result
	 */
	if (inexact && (dest_exponent > 0 || Is_underflowtrap_enabled())) {
		Dbl_clear_signexponent(opnd3p1);
		switch (Rounding_mode()) {
			case ROUNDPLUS:
				if (Dbl_iszero_sign(resultp1))
					Dbl_increment(opnd3p1,opnd3p2);
				break;
			case ROUNDMINUS:
				if (Dbl_isone_sign(resultp1))
					Dbl_increment(opnd3p1,opnd3p2);
				break;
			case ROUNDNEAREST:
				if (guardbit && (stickybit ||
				    Dbl_isone_lowmantissap2(opnd3p2))) {
					Dbl_increment(opnd3p1,opnd3p2);
				}
		}
		if (Dbl_isone_hidden(opnd3p1)) dest_exponent++;
	}
	Dbl_set_mantissa(resultp1,resultp2,opnd3p1,opnd3p2);

        /*
         * Test for overflow
         */
	if (dest_exponent >= DBL_INFINITY_EXPONENT) {
                /* trap if OVERFLOWTRAP enabled */
                if (Is_overflowtrap_enabled()) {
                        /*
                         * Adjust bias of result
                         */
                        Dbl_setwrapped_exponent(resultp1,dest_exponent,ovfl);
                        Dbl_copytoptr(resultp1,resultp2,dstptr);
                        if (inexact)
                            if (Is_inexacttrap_enabled())
                                return(OVERFLOWEXCEPTION | INEXACTEXCEPTION);
                            else Set_inexactflag();
                        return(OVERFLOWEXCEPTION);
                }
		Set_overflowflag();
                /* set result to infinity or largest number */
		Dbl_setoverflow(resultp1,resultp2);
		inexact = TRUE;
	}
        /*
         * Test for underflow
         */
	else if (dest_exponent <= 0) {
                /* trap if UNDERFLOWTRAP enabled */
                if (Is_underflowtrap_enabled()) {
                        /*
                         * Adjust bias of result
                         */
                        Dbl_setwrapped_exponent(resultp1,dest_exponent,unfl);
                        Dbl_copytoptr(resultp1,resultp2,dstptr);
                        if (inexact)
                            if (Is_inexacttrap_enabled())
                                return(UNDERFLOWEXCEPTION | INEXACTEXCEPTION);
                            else Set_inexactflag();
                        return(UNDERFLOWEXCEPTION);
                }

		/* Determine if should set underflow flag */
		is_tiny = TRUE;
		if (dest_exponent == 0 && inexact) {
			switch (Rounding_mode()) {
			case ROUNDPLUS:
				if (Dbl_iszero_sign(resultp1)) {
					Dbl_increment(opnd3p1,opnd3p2);
					if (Dbl_isone_hiddenoverflow(opnd3p1))
					    is_tiny = FALSE;
					Dbl_decrement(opnd3p1,opnd3p2);
				}
				break;
			case ROUNDMINUS:
				if (Dbl_isone_sign(resultp1)) {
					Dbl_increment(opnd3p1,opnd3p2);
					if (Dbl_isone_hiddenoverflow(opnd3p1))
					    is_tiny = FALSE;
					Dbl_decrement(opnd3p1,opnd3p2);
				}
				break;
			case ROUNDNEAREST:
				if (guardbit && (stickybit ||
				    Dbl_isone_lowmantissap2(opnd3p2))) {
					Dbl_increment(opnd3p1,opnd3p2);
					if (Dbl_isone_hiddenoverflow(opnd3p1))
					    is_tiny = FALSE;
					Dbl_decrement(opnd3p1,opnd3p2);
				}
				break;
			}
		}

                /*
                 * denormalize result or set to signed zero
                 */
		stickybit = inexact;
		Dbl_denormalize(opnd3p1,opnd3p2,dest_exponent,guardbit,
		 stickybit,inexact);

		/* return rounded number */
		if (inexact) {
			switch (Rounding_mode()) {
			case ROUNDPLUS:
				if (Dbl_iszero_sign(resultp1)) {
					Dbl_increment(opnd3p1,opnd3p2);
				}
				break;
			case ROUNDMINUS:
				if (Dbl_isone_sign(resultp1)) {
					Dbl_increment(opnd3p1,opnd3p2);
				}
				break;
			case ROUNDNEAREST:
				if (guardbit && (stickybit ||
				    Dbl_isone_lowmantissap2(opnd3p2))) {
					Dbl_increment(opnd3p1,opnd3p2);
				}
				break;
			}
			if (is_tiny) Set_underflowflag();
                }
		Dbl_set_exponentmantissa(resultp1,resultp2,opnd3p1,opnd3p2);
	}
	else Dbl_set_exponent(resultp1,dest_exponent);
	Dbl_copytoptr(resultp1,resultp2,dstptr);

	/* check for inexact */
	if (inexact) {
		if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
		else Set_inexactflag();
	}
	return(NOEXCEPTION);
}
Пример #5
0
u_int
decode_fpu(unsigned int Fpu_register[], unsigned int trap_counts[])
{
    unsigned int current_ir, excp;
    int target, exception_index = 1;
    boolean inexact;
    unsigned int aflags;
    unsigned int bflags;
    unsigned int excptype;


    /* Keep stats on how many floating point exceptions (based on type)
     * that happen.  Want to keep this overhead low, but still provide
     * some information to the customer.  All exits from this routine
     * need to restore Fpu_register[0]
    */

    bflags=(Fpu_register[0] & 0xf8000000);
    Fpu_register[0] &= 0x07ffffff;

    /* exception_index is used to index the exception register queue.  It
     *   always points at the last register that contains a valid exception.  A
     *   zero value implies no exceptions (also the initialized value).  Setting
     *   the T-bit resets the exception_index to zero.
     */

    /*
     * Check for reserved-op exception.  A reserved-op exception does not 
     * set any exception registers nor does it set the T-bit.  If the T-bit
     * is not set then a reserved-op exception occurred.
     *
     * At some point, we may want to report reserved op exceptions as
     * illegal instructions.
     */
    
    if (!Is_tbit_set()) {
	update_trap_counts(Fpu_register, aflags, bflags, trap_counts);
	return SIGNALCODE(SIGILL, ILL_COPROC);
    }

    /* 
     * Is a coprocessor op. 
     *
     * Now we need to determine what type of exception occurred.
     */
    for (exception_index=1; exception_index<=MAX_EXCP_REG; exception_index++) {
	current_ir = Excp_instr(exception_index);
	  /*
	   * On PA89: there are 5 different unimplemented exception
	   * codes: 0x1, 0x9, 0xb, 0x3, and 0x23.  PA-RISC 2.0 adds
	   * another, 0x2b.  Only these have the low order bit set.
	   */
	excptype = Excp_type(exception_index);
	if (excptype & UNIMPLEMENTEDEXCEPTION) {
		/*
		 * Clear T-bit and exception register so that
		 * we can tell if a trap really occurs while 
		 * emulating the instruction.
		 */
		Clear_tbit();
		Clear_excp_register(exception_index);
		/*
		 * Now emulate this instruction.  If a trap occurs,
		 * fpudispatch will return a non-zero number 
		 */
		excp = fpudispatch(current_ir,excptype,0,Fpu_register);
		/* accumulate the status flags, don't lose them as in hpux */
		if (excp) {
			/*
			 * We now need to make sure that the T-bit and the
			 * exception register contain the correct values
			 * before continuing.
			 */
			/*
			 * Set t-bit since it might still be needed for a
			 * subsequent real trap (I don't understand fully -PB)
			 */
			Set_tbit();
			/* some of the following code uses
			 * Excp_type(exception_index) so fix that up */
			Set_exceptiontype_and_instr_field(excp,current_ir,
			 Fpu_register[exception_index]);
			if (excp == UNIMPLEMENTEDEXCEPTION) {
				/*
			 	 * it is really unimplemented, so restore the
			 	 * TIMEX extended unimplemented exception code
			 	 */
				excp = excptype;
				update_trap_counts(Fpu_register, aflags, bflags, 
					   trap_counts);
				return SIGNALCODE(SIGILL, ILL_COPROC);
			}
			/* some of the following code uses excptype, so
			 * fix that up too */
			excptype = excp;
		}
		/* handle exceptions other than the real UNIMPLIMENTED the
		 * same way as if the hardware had caused them */
		if (excp == NOEXCEPTION)
			/* For now use 'break', should technically be 'continue' */
			break;
	}

	  /*
	   * In PA89, the underflow exception has been extended to encode
	   * additional information.  The exception looks like pp01x0,
	   * where x is 1 if inexact and pp represent the inexact bit (I)
	   * and the round away bit (RA)
	   */
	if (excptype & UNDERFLOWEXCEPTION) {
		/* check for underflow trap enabled */
		if (Is_underflowtrap_enabled()) {
			update_trap_counts(Fpu_register, aflags, bflags, 
					   trap_counts);
			return SIGNALCODE(SIGFPE, FPE_FLTUND);
		} else {
		    /*
		     * Isn't a real trap; we need to 
		     * return the default value.
		     */
		    target = current_ir & fivebits;
#ifndef lint
		    if (Ibit(Fpu_register[exception_index])) inexact = TRUE;
		    else inexact = FALSE;
#endif
		    switch (Excp_format()) {
		      case SGL:
		        /*
		         * If ra (round-away) is set, will 
		         * want to undo the rounding done
		         * by the hardware.
		         */
		        if (Rabit(Fpu_register[exception_index])) 
				Sgl_decrement(Fpu_sgl(target));

			/* now denormalize */
			sgl_denormalize(&Fpu_sgl(target),&inexact,Rounding_mode());
		    	break;
		      case DBL:
		    	/*
		    	 * If ra (round-away) is set, will 
		    	 * want to undo the rounding done
		    	 * by the hardware.
		    	 */
		    	if (Rabit(Fpu_register[exception_index])) 
				Dbl_decrement(Fpu_dblp1(target),Fpu_dblp2(target));

			/* now denormalize */
			dbl_denormalize(&Fpu_dblp1(target),&Fpu_dblp2(target),
			  &inexact,Rounding_mode());
		    	break;
		    }
		    if (inexact) Set_underflowflag();
		    /* 
		     * Underflow can generate an inexact
		     * exception.  If inexact trap is enabled,
		     * want to do an inexact trap, otherwise 
		     * set inexact flag.
		     */
		    if (inexact && Is_inexacttrap_enabled()) {
		    	/*
		    	 * Set exception field of exception register
		    	 * to inexact, parm field to zero.
			 * Underflow bit should be cleared.
		    	 */
		    	Set_exceptiontype(Fpu_register[exception_index],
			 INEXACTEXCEPTION);
			Set_parmfield(Fpu_register[exception_index],0);
			update_trap_counts(Fpu_register, aflags, bflags, 
					   trap_counts);
			return SIGNALCODE(SIGFPE, FPE_FLTRES);
		    }
		    else {
		    	/*
		    	 * Exception register needs to be cleared.  
			 * Inexact flag needs to be set if inexact.
		    	 */
		    	Clear_excp_register(exception_index);
		    	if (inexact) Set_inexactflag();
		    }
		}
		continue;
	}
	switch(Excp_type(exception_index)) {
	  case OVERFLOWEXCEPTION:
	  case OVERFLOWEXCEPTION | INEXACTEXCEPTION:
		/* check for overflow trap enabled */
			update_trap_counts(Fpu_register, aflags, bflags, 
					   trap_counts);
		if (Is_overflowtrap_enabled()) {
			update_trap_counts(Fpu_register, aflags, bflags, 
					   trap_counts);
			return SIGNALCODE(SIGFPE, FPE_FLTOVF);
		} else {
			/*
			 * Isn't a real trap; we need to 
			 * return the default value.
			 */
			target = current_ir & fivebits;
			switch (Excp_format()) {
			  case SGL: 
				Sgl_setoverflow(Fpu_sgl(target));
				break;
			  case DBL:
				Dbl_setoverflow(Fpu_dblp1(target),Fpu_dblp2(target));
				break;
			}
			Set_overflowflag();
			/* 
			 * Overflow always generates an inexact
			 * exception.  If inexact trap is enabled,
			 * want to do an inexact trap, otherwise 
			 * set inexact flag.
			 */
			if (Is_inexacttrap_enabled()) {
				/*
				 * Set exception field of exception
				 * register to inexact.  Overflow
				 * bit should be cleared.
				 */
				Set_exceptiontype(Fpu_register[exception_index],
				 INEXACTEXCEPTION);
				update_trap_counts(Fpu_register, aflags, bflags,
					   trap_counts);
				return SIGNALCODE(SIGFPE, FPE_FLTRES);
			}
			else {
				/*
				 * Exception register needs to be cleared.  
				 * Inexact flag needs to be set.
				 */
				Clear_excp_register(exception_index);
				Set_inexactflag();
			}
		}
		break;
	  case INVALIDEXCEPTION:
	  case OPC_2E_INVALIDEXCEPTION:
		update_trap_counts(Fpu_register, aflags, bflags, trap_counts);
		return SIGNALCODE(SIGFPE, FPE_FLTINV);
	  case DIVISIONBYZEROEXCEPTION:
		update_trap_counts(Fpu_register, aflags, bflags, trap_counts);
	  	return SIGNALCODE(SIGFPE, FPE_FLTDIV);
	  case INEXACTEXCEPTION:
		update_trap_counts(Fpu_register, aflags, bflags, trap_counts);
		return SIGNALCODE(SIGFPE, FPE_FLTRES);
	  default:
		update_trap_counts(Fpu_register, aflags, bflags, trap_counts);
		printk("%s(%d) Unknown FPU exception 0x%x\n", __FILE__,
			__LINE__, Excp_type(exception_index));
		return SIGNALCODE(SIGILL, ILL_COPROC);
	  case NOEXCEPTION:	/* no exception */
		/*
		 * Clear exception register in case 
		 * other fields are non-zero.
		 */
		Clear_excp_register(exception_index);
		break;
	}
    }
    /*
     * No real exceptions occurred.
     */
    Clear_tbit();
    update_trap_counts(Fpu_register, aflags, bflags, trap_counts);
    return(NOTRAP);
}
Пример #6
0
int
dbl_fmpy(
	    dbl_floating_point *srcptr1,
	    dbl_floating_point *srcptr2,
	    dbl_floating_point *dstptr,
	    unsigned int *status)
{
	register unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2;
	register unsigned int opnd3p1, opnd3p2, resultp1, resultp2;
	register int dest_exponent, count;
	register boolean inexact = FALSE, guardbit = FALSE, stickybit = FALSE;
	boolean is_tiny;

	Dbl_copyfromptr(srcptr1,opnd1p1,opnd1p2);
	Dbl_copyfromptr(srcptr2,opnd2p1,opnd2p2);

	/*
	 * set sign bit of result
	 */
	if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1))
		Dbl_setnegativezerop1(resultp1);
	else Dbl_setzerop1(resultp1);
	/*
	 * check first operand for NaN's or infinity
	 */
	if (Dbl_isinfinity_exponent(opnd1p1)) {
		if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
			if (Dbl_isnotnan(opnd2p1,opnd2p2)) {
				if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) {
					/*
					 * invalid since operands are infinity
					 * and zero
					 */
					if (Is_invalidtrap_enabled())
                                		return(INVALIDEXCEPTION);
                                	Set_invalidflag();
                                	Dbl_makequietnan(resultp1,resultp2);
					Dbl_copytoptr(resultp1,resultp2,dstptr);
					return(NOEXCEPTION);
				}
				/*
			 	 * return infinity
			 	 */
				Dbl_setinfinity_exponentmantissa(resultp1,resultp2);
				Dbl_copytoptr(resultp1,resultp2,dstptr);
				return(NOEXCEPTION);
			}
		}
		else {
                	/*
                 	 * is NaN; signaling or quiet?
                 	 */
                	if (Dbl_isone_signaling(opnd1p1)) {
                        	/* trap if INVALIDTRAP enabled */
                        	if (Is_invalidtrap_enabled())
                            		return(INVALIDEXCEPTION);
                        	/* make NaN quiet */
                        	Set_invalidflag();
                        	Dbl_set_quiet(opnd1p1);
                	}
			/*
			 * is second operand a signaling NaN?
			 */
			else if (Dbl_is_signalingnan(opnd2p1)) {
                        	/* trap if INVALIDTRAP enabled */
                        	if (Is_invalidtrap_enabled())
                            		return(INVALIDEXCEPTION);
                        	/* make NaN quiet */
                        	Set_invalidflag();
                        	Dbl_set_quiet(opnd2p1);
				Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
                		return(NOEXCEPTION);
			}
                	/*
                 	 * return quiet NaN
                 	 */
			Dbl_copytoptr(opnd1p1,opnd1p2,dstptr);
                	return(NOEXCEPTION);
		}
	}
	/*
	 * check second operand for NaN's or infinity
	 */
	if (Dbl_isinfinity_exponent(opnd2p1)) {
		if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) {
			if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) {
				/* invalid since operands are zero & infinity */
				if (Is_invalidtrap_enabled())
                                	return(INVALIDEXCEPTION);
                                Set_invalidflag();
                                Dbl_makequietnan(opnd2p1,opnd2p2);
				Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
				return(NOEXCEPTION);
			}
			/*
			 * return infinity
			 */
			Dbl_setinfinity_exponentmantissa(resultp1,resultp2);
			Dbl_copytoptr(resultp1,resultp2,dstptr);
			return(NOEXCEPTION);
		}
                /*
                 * is NaN; signaling or quiet?
                 */
                if (Dbl_isone_signaling(opnd2p1)) {
                        /* trap if INVALIDTRAP enabled */
                        if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
                        /* make NaN quiet */
                        Set_invalidflag();
                        Dbl_set_quiet(opnd2p1);
                }
                /*
                 * return quiet NaN
                 */
		Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
                return(NOEXCEPTION);
	}
	/*
	 * Generate exponent
	 */
	dest_exponent = Dbl_exponent(opnd1p1) + Dbl_exponent(opnd2p1) -DBL_BIAS;

	/*
	 * Generate mantissa
	 */
	if (Dbl_isnotzero_exponent(opnd1p1)) {
		/* set hidden bit */
		Dbl_clear_signexponent_set_hidden(opnd1p1);
	}
	else {
		/* check for zero */
		if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
			Dbl_setzero_exponentmantissa(resultp1,resultp2);
			Dbl_copytoptr(resultp1,resultp2,dstptr);
			return(NOEXCEPTION);
		}
                /* is denormalized, adjust exponent */
                Dbl_clear_signexponent(opnd1p1);
                Dbl_leftshiftby1(opnd1p1,opnd1p2);
		Dbl_normalize(opnd1p1,opnd1p2,dest_exponent);
	}
	/* opnd2 needs to have hidden bit set with msb in hidden bit */
	if (Dbl_isnotzero_exponent(opnd2p1)) {
		Dbl_clear_signexponent_set_hidden(opnd2p1);
	}
	else {
		/* check for zero */
		if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) {
			Dbl_setzero_exponentmantissa(resultp1,resultp2);
			Dbl_copytoptr(resultp1,resultp2,dstptr);
			return(NOEXCEPTION);
		}
                /* is denormalized; want to normalize */
                Dbl_clear_signexponent(opnd2p1);
                Dbl_leftshiftby1(opnd2p1,opnd2p2);
		Dbl_normalize(opnd2p1,opnd2p2,dest_exponent);
	}

	/* Multiply two source mantissas together */

	/* make room for guard bits */
	Dbl_leftshiftby7(opnd2p1,opnd2p2);
	Dbl_setzero(opnd3p1,opnd3p2);
        /*
         * Four bits at a time are inspected in each loop, and a
         * simple shift and add multiply algorithm is used.
         */
	for (count=1;count<=DBL_P;count+=4) {
		stickybit |= Dlow4p2(opnd3p2);
		Dbl_rightshiftby4(opnd3p1,opnd3p2);
		if (Dbit28p2(opnd1p2)) {
	 		/* Twoword_add should be an ADDC followed by an ADD. */
                        Twoword_add(opnd3p1, opnd3p2, opnd2p1<<3 | opnd2p2>>29,
				    opnd2p2<<3);
		}
		if (Dbit29p2(opnd1p2)) {
                        Twoword_add(opnd3p1, opnd3p2, opnd2p1<<2 | opnd2p2>>30,
				    opnd2p2<<2);
		}
		if (Dbit30p2(opnd1p2)) {
                        Twoword_add(opnd3p1, opnd3p2, opnd2p1<<1 | opnd2p2>>31,
				    opnd2p2<<1);
		}
		if (Dbit31p2(opnd1p2)) {
                        Twoword_add(opnd3p1, opnd3p2, opnd2p1, opnd2p2);
		}
		Dbl_rightshiftby4(opnd1p1,opnd1p2);
	}
	if (Dbit3p1(opnd3p1)==0) {
		Dbl_leftshiftby1(opnd3p1,opnd3p2);
	}
	else {
		/* result mantissa >= 2. */
		dest_exponent++;
	}
	/* check for denormalized result */
	while (Dbit3p1(opnd3p1)==0) {
		Dbl_leftshiftby1(opnd3p1,opnd3p2);
		dest_exponent--;
	}
	/*
	 * check for guard, sticky and inexact bits
	 */
	stickybit |= Dallp2(opnd3p2) << 25;
	guardbit = (Dallp2(opnd3p2) << 24) >> 31;
	inexact = guardbit | stickybit;

	/* align result mantissa */
	Dbl_rightshiftby8(opnd3p1,opnd3p2);

	/*
	 * round result
	 */
	if (inexact && (dest_exponent>0 || Is_underflowtrap_enabled())) {
		Dbl_clear_signexponent(opnd3p1);
		switch (Rounding_mode()) {
			case ROUNDPLUS:
				if (Dbl_iszero_sign(resultp1))
					Dbl_increment(opnd3p1,opnd3p2);
				break;
			case ROUNDMINUS:
				if (Dbl_isone_sign(resultp1))
					Dbl_increment(opnd3p1,opnd3p2);
				break;
			case ROUNDNEAREST:
				if (guardbit) {
			   	if (stickybit || Dbl_isone_lowmantissap2(opnd3p2))
			      	Dbl_increment(opnd3p1,opnd3p2);
				}
		}
		if (Dbl_isone_hidden(opnd3p1)) dest_exponent++;
	}
	Dbl_set_mantissa(resultp1,resultp2,opnd3p1,opnd3p2);

        /*
         * Test for overflow
         */
	if (dest_exponent >= DBL_INFINITY_EXPONENT) {
                /* trap if OVERFLOWTRAP enabled */
                if (Is_overflowtrap_enabled()) {
                        /*
                         * Adjust bias of result
                         */
			Dbl_setwrapped_exponent(resultp1,dest_exponent,ovfl);
			Dbl_copytoptr(resultp1,resultp2,dstptr);
			if (inexact)
			    if (Is_inexacttrap_enabled())
				return (OVERFLOWEXCEPTION | INEXACTEXCEPTION);
			    else Set_inexactflag();
			return (OVERFLOWEXCEPTION);
                }
		inexact = TRUE;
		Set_overflowflag();
                /* set result to infinity or largest number */
		Dbl_setoverflow(resultp1,resultp2);
	}
        /*
         * Test for underflow
         */
	else if (dest_exponent <= 0) {
                /* trap if UNDERFLOWTRAP enabled */
                if (Is_underflowtrap_enabled()) {
                        /*
                         * Adjust bias of result
                         */
			Dbl_setwrapped_exponent(resultp1,dest_exponent,unfl);
			Dbl_copytoptr(resultp1,resultp2,dstptr);
			if (inexact)
			    if (Is_inexacttrap_enabled())
				return (UNDERFLOWEXCEPTION | INEXACTEXCEPTION);
			    else Set_inexactflag();
			return (UNDERFLOWEXCEPTION);
                }

		/* Determine if should set underflow flag */
		is_tiny = TRUE;
		if (dest_exponent == 0 && inexact) {
			switch (Rounding_mode()) {
			case ROUNDPLUS:
				if (Dbl_iszero_sign(resultp1)) {
					Dbl_increment(opnd3p1,opnd3p2);
					if (Dbl_isone_hiddenoverflow(opnd3p1))
                			    is_tiny = FALSE;
					Dbl_decrement(opnd3p1,opnd3p2);
				}
				break;
			case ROUNDMINUS:
				if (Dbl_isone_sign(resultp1)) {
					Dbl_increment(opnd3p1,opnd3p2);
					if (Dbl_isone_hiddenoverflow(opnd3p1))
                			    is_tiny = FALSE;
					Dbl_decrement(opnd3p1,opnd3p2);
				}
				break;
			case ROUNDNEAREST:
				if (guardbit && (stickybit ||
				    Dbl_isone_lowmantissap2(opnd3p2))) {
				      	Dbl_increment(opnd3p1,opnd3p2);
					if (Dbl_isone_hiddenoverflow(opnd3p1))
                			    is_tiny = FALSE;
					Dbl_decrement(opnd3p1,opnd3p2);
				}
				break;
			}
		}

		/*
		 * denormalize result or set to signed zero
		 */
		stickybit = inexact;
		Dbl_denormalize(opnd3p1,opnd3p2,dest_exponent,guardbit,
		 stickybit,inexact);

		/* return zero or smallest number */
		if (inexact) {
			switch (Rounding_mode()) {
			case ROUNDPLUS:
				if (Dbl_iszero_sign(resultp1)) {
					Dbl_increment(opnd3p1,opnd3p2);
				}
				break;
			case ROUNDMINUS:
				if (Dbl_isone_sign(resultp1)) {
					Dbl_increment(opnd3p1,opnd3p2);
				}
				break;
			case ROUNDNEAREST:
				if (guardbit && (stickybit ||
				    Dbl_isone_lowmantissap2(opnd3p2))) {
			      		Dbl_increment(opnd3p1,opnd3p2);
				}
				break;
			}
                	if (is_tiny) Set_underflowflag();
		}
		Dbl_set_exponentmantissa(resultp1,resultp2,opnd3p1,opnd3p2);
	}
	else Dbl_set_exponent(resultp1,dest_exponent);
	/* check for inexact */
	Dbl_copytoptr(resultp1,resultp2,dstptr);
	if (inexact) {
		if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
		else Set_inexactflag();
	}
	return(NOEXCEPTION);
}
Пример #7
0
int
dbl_fdiv (dbl_floating_point * srcptr1, dbl_floating_point * srcptr2,
	  dbl_floating_point * dstptr, unsigned int *status)
{
	register unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2;
	register unsigned int opnd3p1, opnd3p2, resultp1, resultp2;
	register int dest_exponent, count;
	register boolean inexact = FALSE, guardbit = FALSE, stickybit = FALSE;
	boolean is_tiny;

	Dbl_copyfromptr(srcptr1,opnd1p1,opnd1p2);
	Dbl_copyfromptr(srcptr2,opnd2p1,opnd2p2);
	/* 
                           
  */
	if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1)) 
		Dbl_setnegativezerop1(resultp1);  
	else Dbl_setzerop1(resultp1);
	/*
                                             
  */
	if (Dbl_isinfinity_exponent(opnd1p1)) {
		if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
			if (Dbl_isnotnan(opnd2p1,opnd2p2)) {
				if (Dbl_isinfinity(opnd2p1,opnd2p2)) {
					/* 
                                    
                     
      */
					if (Is_invalidtrap_enabled())
                                		return(INVALIDEXCEPTION);
                                	Set_invalidflag();
                                	Dbl_makequietnan(resultp1,resultp2);
					Dbl_copytoptr(resultp1,resultp2,dstptr);
					return(NOEXCEPTION);
				}
				/*
                       
      */
				Dbl_setinfinity_exponentmantissa(resultp1,resultp2);
				Dbl_copytoptr(resultp1,resultp2,dstptr);
				return(NOEXCEPTION);
			}
		}
		else {
                	/*
                                                
                   */
                	if (Dbl_isone_signaling(opnd1p1)) {
                        	/*                             */
                        	if (Is_invalidtrap_enabled())
                            		return(INVALIDEXCEPTION);
                        	/*                */
                        	Set_invalidflag();
                        	Dbl_set_quiet(opnd1p1);
                	}
			/* 
                                         
    */
			else if (Dbl_is_signalingnan(opnd2p1)) {
                        	/*                             */
                        	if (Is_invalidtrap_enabled())
                            		return(INVALIDEXCEPTION);
                        	/*                */
                        	Set_invalidflag();
                        	Dbl_set_quiet(opnd2p1);
				Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
                		return(NOEXCEPTION);
			}
                	/*
                                     
                   */
			Dbl_copytoptr(opnd1p1,opnd1p2,dstptr);
                	return(NOEXCEPTION);
		}
	}
	/*
                                              
  */
	if (Dbl_isinfinity_exponent(opnd2p1)) {
		if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) {
			/*
                 
    */
			Dbl_setzero_exponentmantissa(resultp1,resultp2);
			Dbl_copytoptr(resultp1,resultp2,dstptr);
			return(NOEXCEPTION);
		}
                /*
                                              
                 */
                if (Dbl_isone_signaling(opnd2p1)) {
                        /*                             */
                        if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
                        /*                */
                        Set_invalidflag();
                        Dbl_set_quiet(opnd2p1);
                }
                /*
                                   
                 */
		Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
                return(NOEXCEPTION);
	}
        /*
                                     
         */
        if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) {
                if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) {
                        /*                                      */
                        if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
                        Set_invalidflag();
                        Dbl_makequietnan(resultp1,resultp2);
                        Dbl_copytoptr(resultp1,resultp2,dstptr);
                        return(NOEXCEPTION);
                }
                if (Is_divisionbyzerotrap_enabled())
                       	return(DIVISIONBYZEROEXCEPTION);
                Set_divisionbyzeroflag();
                Dbl_setinfinity_exponentmantissa(resultp1,resultp2);
                Dbl_copytoptr(resultp1,resultp2,dstptr);
                return(NOEXCEPTION);
        }
	/*
                      
  */
	dest_exponent = Dbl_exponent(opnd1p1) - Dbl_exponent(opnd2p1) + DBL_BIAS;

	/*
                     
  */
	if (Dbl_isnotzero_exponent(opnd1p1)) {
		/*                */
		Dbl_clear_signexponent_set_hidden(opnd1p1);
	}
	else {
		/*                */
		if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
			Dbl_setzero_exponentmantissa(resultp1,resultp2);
			Dbl_copytoptr(resultp1,resultp2,dstptr);
			return(NOEXCEPTION);
		}
                /*                                    */
                Dbl_clear_signexponent(opnd1p1);
                Dbl_leftshiftby1(opnd1p1,opnd1p2);
		Dbl_normalize(opnd1p1,opnd1p2,dest_exponent);
	}
	/*                                                           */
	if (Dbl_isnotzero_exponent(opnd2p1)) {
		Dbl_clear_signexponent_set_hidden(opnd2p1);
	}
	else {
                /*                                    */
                Dbl_clear_signexponent(opnd2p1);
                Dbl_leftshiftby1(opnd2p1,opnd2p2);
                while (Dbl_iszero_hiddenhigh7mantissa(opnd2p1)) {
                        dest_exponent+=8;
                        Dbl_leftshiftby8(opnd2p1,opnd2p2);
                }
                if (Dbl_iszero_hiddenhigh3mantissa(opnd2p1)) {
                        dest_exponent+=4;
                        Dbl_leftshiftby4(opnd2p1,opnd2p2);
                }
                while (Dbl_iszero_hidden(opnd2p1)) {
                        dest_exponent++;
                        Dbl_leftshiftby1(opnd2p1,opnd2p2);
                }
	}

	/*                             */

	/* 
                                             
  */
	Twoword_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2);
	Dbl_setzero(opnd3p1,opnd3p2);
	for (count=1; count <= DBL_P && (opnd1p1 || opnd1p2); count++) {
		Dbl_leftshiftby1(opnd1p1,opnd1p2);
		Dbl_leftshiftby1(opnd3p1,opnd3p2);
		if (Dbl_iszero_sign(opnd1p1)) {
			Dbl_setone_lowmantissap2(opnd3p2);
			Twoword_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2);
		}
		else {
			Twoword_add(opnd1p1, opnd1p2, opnd2p1, opnd2p2);
		}
	}
	if (count <= DBL_P) {
		Dbl_leftshiftby1(opnd3p1,opnd3p2);
		Dbl_setone_lowmantissap2(opnd3p2);
		Dbl_leftshift(opnd3p1,opnd3p2,(DBL_P-count));
		if (Dbl_iszero_hidden(opnd3p1)) {
			Dbl_leftshiftby1(opnd3p1,opnd3p2);
			dest_exponent--;
		}
	}
	else {
		if (Dbl_iszero_hidden(opnd3p1)) {
			/*                                    */
			Dbl_leftshiftby1(opnd1p1,opnd1p2);
			Dbl_leftshiftby1(opnd3p1,opnd3p2);
			if (Dbl_iszero_sign(opnd1p1)) {
				Dbl_setone_lowmantissap2(opnd3p2);
				Twoword_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2);
			}
			else {
				Twoword_add(opnd1p1,opnd1p2,opnd2p1,opnd2p2);
			}
			dest_exponent--;
		}
		if (Dbl_iszero_sign(opnd1p1)) guardbit = TRUE;
		stickybit = Dbl_allp1(opnd1p1) || Dbl_allp2(opnd1p2);
	}
	inexact = guardbit | stickybit;

	/* 
                 
  */
	if (inexact && (dest_exponent > 0 || Is_underflowtrap_enabled())) {
		Dbl_clear_signexponent(opnd3p1);
		switch (Rounding_mode()) {
			case ROUNDPLUS: 
				if (Dbl_iszero_sign(resultp1)) 
					Dbl_increment(opnd3p1,opnd3p2);
				break;
			case ROUNDMINUS: 
				if (Dbl_isone_sign(resultp1)) 
					Dbl_increment(opnd3p1,opnd3p2);
				break;
			case ROUNDNEAREST:
				if (guardbit && (stickybit || 
				    Dbl_isone_lowmantissap2(opnd3p2))) {
			      		Dbl_increment(opnd3p1,opnd3p2);
				}
		}
		if (Dbl_isone_hidden(opnd3p1)) dest_exponent++;
	}
	Dbl_set_mantissa(resultp1,resultp2,opnd3p1,opnd3p2);

        /* 
                            
         */
	if (dest_exponent >= DBL_INFINITY_EXPONENT) {
                /*                              */
                if (Is_overflowtrap_enabled()) {
                        /*
                                                
                         */
                        Dbl_setwrapped_exponent(resultp1,dest_exponent,ovfl);
                        Dbl_copytoptr(resultp1,resultp2,dstptr);
                        if (inexact) 
                            if (Is_inexacttrap_enabled())
                                return(OVERFLOWEXCEPTION | INEXACTEXCEPTION);
                            else Set_inexactflag();
                        return(OVERFLOWEXCEPTION);
                }
		Set_overflowflag();
                /*                                          */
		Dbl_setoverflow(resultp1,resultp2);
		inexact = TRUE;
	}
        /* 
                             
         */
	else if (dest_exponent <= 0) {
                /*                               */
                if (Is_underflowtrap_enabled()) {
                        /*
                                                
                         */
                        Dbl_setwrapped_exponent(resultp1,dest_exponent,unfl);
                        Dbl_copytoptr(resultp1,resultp2,dstptr);
                        if (inexact) 
                            if (Is_inexacttrap_enabled())
                                return(UNDERFLOWEXCEPTION | INEXACTEXCEPTION);
                            else Set_inexactflag();
                        return(UNDERFLOWEXCEPTION);
                }

		/*                                        */
		is_tiny = TRUE;
		if (dest_exponent == 0 && inexact) {
			switch (Rounding_mode()) {
			case ROUNDPLUS: 
				if (Dbl_iszero_sign(resultp1)) {
					Dbl_increment(opnd3p1,opnd3p2);
					if (Dbl_isone_hiddenoverflow(opnd3p1))
                			    is_tiny = FALSE;
					Dbl_decrement(opnd3p1,opnd3p2);
				}
				break;
			case ROUNDMINUS: 
				if (Dbl_isone_sign(resultp1)) {
					Dbl_increment(opnd3p1,opnd3p2);
					if (Dbl_isone_hiddenoverflow(opnd3p1))
                			    is_tiny = FALSE;
					Dbl_decrement(opnd3p1,opnd3p2);
				}
				break;
			case ROUNDNEAREST:
				if (guardbit && (stickybit || 
				    Dbl_isone_lowmantissap2(opnd3p2))) {
				      	Dbl_increment(opnd3p1,opnd3p2);
					if (Dbl_isone_hiddenoverflow(opnd3p1))
                			    is_tiny = FALSE;
					Dbl_decrement(opnd3p1,opnd3p2);
				}
				break;
			}
		}

                /*
                                                           
                 */
		stickybit = inexact;
		Dbl_denormalize(opnd3p1,opnd3p2,dest_exponent,guardbit,
		 stickybit,inexact);

		/*                       */ 
		if (inexact) {
			switch (Rounding_mode()) {
			case ROUNDPLUS:
				if (Dbl_iszero_sign(resultp1)) {
					Dbl_increment(opnd3p1,opnd3p2);
				}
				break;
			case ROUNDMINUS: 
				if (Dbl_isone_sign(resultp1)) {
					Dbl_increment(opnd3p1,opnd3p2);
				}
				break;
			case ROUNDNEAREST:
				if (guardbit && (stickybit || 
				    Dbl_isone_lowmantissap2(opnd3p2))) {
			      		Dbl_increment(opnd3p1,opnd3p2);
				}
				break;
			}
                	if (is_tiny) Set_underflowflag();
                }
		Dbl_set_exponentmantissa(resultp1,resultp2,opnd3p1,opnd3p2);
	}
	else Dbl_set_exponent(resultp1,dest_exponent);
	Dbl_copytoptr(resultp1,resultp2,dstptr);

	/*                   */
	if (inexact) {
		if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
		else Set_inexactflag();
	}
	return(NOEXCEPTION);
}
Пример #8
0
int
sgl_fsub(
	    sgl_floating_point *leftptr,
	    sgl_floating_point *rightptr,
	    sgl_floating_point *dstptr,
	    unsigned int *status)
    {
    register unsigned int left, right, result, extent;
    register unsigned int signless_upper_left, signless_upper_right, save;
    
    register int result_exponent, right_exponent, diff_exponent;
    register int sign_save, jumpsize;
    register boolean inexact = FALSE, underflowtrap;
        
    
    left = *leftptr;
    right = *rightptr;

    Sgl_xortointp1(left,right,save);

    if ((result_exponent = Sgl_exponent(left)) == SGL_INFINITY_EXPONENT)
	{
	if (Sgl_iszero_mantissa(left)) 
	    {
	    if (Sgl_isnotnan(right)) 
		{
		if (Sgl_isinfinity(right) && save==0) 
		    {
		    if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
                    Set_invalidflag();
                    Sgl_makequietnan(result);
		    *dstptr = result;
		    return(NOEXCEPTION);
		    }
		*dstptr = left;
		return(NOEXCEPTION);
		}
	    }
	else 
	    {
            if (Sgl_isone_signaling(left)) 
		{
               	
		if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
        	
        	Set_invalidflag();
        	Sgl_set_quiet(left);
        	}
	    else if (Sgl_is_signalingnan(right)) 
		{
        	
               	if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
		
		Set_invalidflag();
		Sgl_set_quiet(right);
		*dstptr = right;
		return(NOEXCEPTION);
		}
 	    *dstptr = left;
 	    return(NOEXCEPTION);
	    }
	} 
    if (Sgl_isinfinity_exponent(right)) 
	{
	if (Sgl_iszero_mantissa(right)) 
	    {
	    
	    Sgl_invert_sign(right);
	    *dstptr = right;
	    return(NOEXCEPTION);
	    }
        if (Sgl_isone_signaling(right)) 
	    {
            
	    if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
	    
	    Set_invalidflag();
	    Sgl_set_quiet(right);
	    }
	*dstptr = right;
	return(NOEXCEPTION);
    	} 

    

    
    Sgl_copytoint_exponentmantissa(left,signless_upper_left);
    Sgl_copytoint_exponentmantissa(right,signless_upper_right);

    
    if(Sgl_ismagnitudeless(signless_upper_left,signless_upper_right))
	{
	Sgl_xorfromintp1(save,right,right);
	Sgl_xorfromintp1(save,left,left);
	result_exponent = Sgl_exponent(left);
	Sgl_invert_sign(left);
	}
     

    if((right_exponent = Sgl_exponent(right)) == 0)
        {
	
	if(Sgl_iszero_mantissa(right)) 
	    {
	    
	    if(Sgl_iszero_exponentmantissa(left))
		{
		
		Sgl_invert_sign(right);
		if(Is_rounding_mode(ROUNDMINUS))
		    {
		    Sgl_or_signs(left,right);
		    }
		else
		    {
		    Sgl_and_signs(left,right);
		    }
		}
	    else 
		{
		if( (result_exponent == 0) && Is_underflowtrap_enabled() )
		    {
		    
	    	    sign_save = Sgl_signextendedsign(left);
		    Sgl_leftshiftby1(left);
		    Sgl_normalize(left,result_exponent);
		    Sgl_set_sign(left,sign_save);
                    Sgl_setwrapped_exponent(left,result_exponent,unfl);
		    *dstptr = left;
		    
		    return(UNDERFLOWEXCEPTION);
		    }
		}
	    *dstptr = left;
	    return(NOEXCEPTION);
	    }

	
	Sgl_clear_sign(right);	
	if(result_exponent == 0 )
	    {
	    if( (int) save >= 0 )
		{
		Sgl_subtract(left,right,result);
		if(Sgl_iszero_mantissa(result))
		    {
		    if(Is_rounding_mode(ROUNDMINUS))
			{
			Sgl_setone_sign(result);
			}
		    else
			{
			Sgl_setzero_sign(result);
			}
		    *dstptr = result;
		    return(NOEXCEPTION);
		    }
		}
	    else
		{
		Sgl_addition(left,right,result);
		if(Sgl_isone_hidden(result))
		    {
		    *dstptr = result;
		    return(NOEXCEPTION);
		    }
		}
	    if(Is_underflowtrap_enabled())
		{
		
	    	sign_save = Sgl_signextendedsign(result);
		Sgl_leftshiftby1(result);
		Sgl_normalize(result,result_exponent);
		Sgl_set_sign(result,sign_save);
                Sgl_setwrapped_exponent(result,result_exponent,unfl);
		*dstptr = result;
		
		return(UNDERFLOWEXCEPTION);
		}
	    *dstptr = result;
	    return(NOEXCEPTION);
	    }
	right_exponent = 1;	
	}
    else
	{
	Sgl_clear_signexponent_set_hidden(right);
	}
    Sgl_clear_exponent_set_hidden(left);
    diff_exponent = result_exponent - right_exponent;

    if(diff_exponent > SGL_THRESHOLD)
	{
	diff_exponent = SGL_THRESHOLD;
	}
    
    
    Sgl_right_align(right,diff_exponent,
      extent);

    
    if( (int) save >= 0 )
	{
	Sgl_subtract_withextension(left,right,extent,result);
	if(Sgl_iszero_hidden(result))
	    {
	    
	    sign_save = Sgl_signextendedsign(result);
            Sgl_leftshiftby1_withextent(result,extent,result);

    	    if(Sgl_iszero(result))
		
		{
		if(Is_rounding_mode(ROUNDMINUS)) Sgl_setone_sign(result);
		*dstptr = result;
		return(NOEXCEPTION);
		}
	    result_exponent--;
	    
	    if(Sgl_isone_hidden(result))
		{
		if(result_exponent==0)
		    {
		    goto underflow;
		    }
		else
		    {
		    
		    Sgl_set_sign(result,sign_save);
	    	    Ext_leftshiftby1(extent);
		    goto round;
		    }
		}

	    if(!(underflowtrap = Is_underflowtrap_enabled()) &&
	       result_exponent==0) goto underflow;

	    Ext_leftshiftby1(extent);

	    
	    while(Sgl_iszero_hiddenhigh7mantissa(result))
		{
		Sgl_leftshiftby8(result);
		if((result_exponent -= 8) <= 0  && !underflowtrap)
		    goto underflow;
		}
	    
	    if(Sgl_iszero_hiddenhigh3mantissa(result))
		{
		
		Sgl_leftshiftby4(result);
		if((result_exponent -= 4) <= 0 && !underflowtrap)
		    goto underflow;
		}
	    if((jumpsize = Sgl_hiddenhigh3mantissa(result)) > 7)
		{
		
		if(result_exponent <= 0) goto underflow;
		Sgl_set_sign(result,sign_save);
		Sgl_set_exponent(result,result_exponent);
		*dstptr = result;
		return(NOEXCEPTION);
		}
	    Sgl_sethigh4bits(result,sign_save);
	    switch(jumpsize) 
		{
		case 1:
		    {
		    Sgl_leftshiftby3(result);
		    result_exponent -= 3;
		    break;
		    }
		case 2:
		case 3:
		    {
		    Sgl_leftshiftby2(result);
		    result_exponent -= 2;
		    break;
		    }
		case 4:
		case 5:
		case 6:
		case 7:
		    {
		    Sgl_leftshiftby1(result);
		    result_exponent -= 1;
		    break;
		    }
		}
	    if(result_exponent > 0) 
		{
		Sgl_set_exponent(result,result_exponent);
		*dstptr = result;	
		return(NOEXCEPTION);
		}
	    
	  underflow:
	    if(Is_underflowtrap_enabled())
		{
		Sgl_set_sign(result,sign_save);
                Sgl_setwrapped_exponent(result,result_exponent,unfl);
		*dstptr = result;
		
		return(UNDERFLOWEXCEPTION);
		}
	    Sgl_right_align(result,(1-result_exponent),extent);
	    Sgl_clear_signexponent(result);
	    Sgl_set_sign(result,sign_save);
	    *dstptr = result;
	    return(NOEXCEPTION);
	    } 
	
	} 
    else 
	{
	
	Sgl_addition(left,right,result);
	if(Sgl_isone_hiddenoverflow(result))
	    {
	    
	    Sgl_rightshiftby1_withextent(result,extent,extent);
	    Sgl_arithrightshiftby1(result);
	    result_exponent++;
	    } 
	} 
    
  round:
    if(Ext_isnotzero(extent))
	{
	inexact = TRUE;
	switch(Rounding_mode())
	    {
	    case ROUNDNEAREST: 
	    if(Ext_isone_sign(extent))
		{
		
		if(Ext_isnotzero_lower(extent)  ||
		  Sgl_isone_lowmantissa(result))
		    {
		    
		    Sgl_increment(result);
		    }
		}
	    break;

	    case ROUNDPLUS:
	    if(Sgl_iszero_sign(result))
		{
		
		Sgl_increment(result);
		}
	    break;
	    
	    case ROUNDMINUS:
	    if(Sgl_isone_sign(result))
		{
		
		Sgl_increment(result);
		}
	    
	    case ROUNDZERO:;
	    
	    } 
	if(Sgl_isone_hiddenoverflow(result)) result_exponent++;
	}
    if(result_exponent == SGL_INFINITY_EXPONENT)
        {
        
        if(Is_overflowtrap_enabled())
	    {
	    Sgl_setwrapped_exponent(result,result_exponent,ovfl);
	    *dstptr = result;
	    if (inexact)
		if (Is_inexacttrap_enabled())
		    return(OVERFLOWEXCEPTION | INEXACTEXCEPTION);
		else Set_inexactflag();
	    return(OVERFLOWEXCEPTION);
	    }
        else
	    {
	    Set_overflowflag();
	    inexact = TRUE;
	    Sgl_setoverflow(result);
	    }
	}
    else Sgl_set_exponent(result,result_exponent);
    *dstptr = result;
    if(inexact) 
	if(Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
	else Set_inexactflag();
    return(NOEXCEPTION);
    }
Пример #9
0
int
dbl_fmpyfadd(
	    dbl_floating_point *src1ptr,
	    dbl_floating_point *src2ptr,
	    dbl_floating_point *src3ptr,
	    unsigned int *status,
	    dbl_floating_point *dstptr)
{
	unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2, opnd3p1, opnd3p2;
	register unsigned int tmpresp1, tmpresp2, tmpresp3, tmpresp4;
	unsigned int rightp1, rightp2, rightp3, rightp4;
	unsigned int resultp1, resultp2 = 0, resultp3 = 0, resultp4 = 0;
	register int mpy_exponent, add_exponent, count;
	boolean inexact = FALSE, is_tiny = FALSE;

	unsigned int signlessleft1, signlessright1, save;
	register int result_exponent, diff_exponent;
	int sign_save, jumpsize;
	
	Dbl_copyfromptr(src1ptr,opnd1p1,opnd1p2);
	Dbl_copyfromptr(src2ptr,opnd2p1,opnd2p2);
	Dbl_copyfromptr(src3ptr,opnd3p1,opnd3p2);

	if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1)) 
		Dbl_setnegativezerop1(resultp1); 
	else Dbl_setzerop1(resultp1);

	mpy_exponent = Dbl_exponent(opnd1p1) + Dbl_exponent(opnd2p1) - DBL_BIAS;

	if (Dbl_isinfinity_exponent(opnd1p1)) {
		if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
			if (Dbl_isnotnan(opnd2p1,opnd2p2) &&
			    Dbl_isnotnan(opnd3p1,opnd3p2)) {
				if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) {
					if (Is_invalidtrap_enabled())
						return(OPC_2E_INVALIDEXCEPTION);
					Set_invalidflag();
					Dbl_makequietnan(resultp1,resultp2);
					Dbl_copytoptr(resultp1,resultp2,dstptr);
					return(NOEXCEPTION);
				}
				if (Dbl_isinfinity(opnd3p1,opnd3p2) &&
				    (Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) {
					if (Is_invalidtrap_enabled())
						return(OPC_2E_INVALIDEXCEPTION);
					Set_invalidflag();
					Dbl_makequietnan(resultp1,resultp2);
					Dbl_copytoptr(resultp1,resultp2,dstptr);
					return(NOEXCEPTION);
				}

				Dbl_setinfinity_exponentmantissa(resultp1,resultp2);
				Dbl_copytoptr(resultp1,resultp2,dstptr);
				return(NOEXCEPTION);
			}
		}
		else {
			if (Dbl_isone_signaling(opnd1p1)) {
				
				if (Is_invalidtrap_enabled()) 
			    		return(OPC_2E_INVALIDEXCEPTION);
				
				Set_invalidflag();
				Dbl_set_quiet(opnd1p1);
			}
			else if (Dbl_is_signalingnan(opnd2p1)) {
				
				if (Is_invalidtrap_enabled())
			    		return(OPC_2E_INVALIDEXCEPTION);
				
				Set_invalidflag();
				Dbl_set_quiet(opnd2p1);
				Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
				return(NOEXCEPTION);
			}
			else if (Dbl_is_signalingnan(opnd3p1)) {
				
				if (Is_invalidtrap_enabled())
			    		return(OPC_2E_INVALIDEXCEPTION);
				
				Set_invalidflag();
				Dbl_set_quiet(opnd3p1);
				Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
				return(NOEXCEPTION);
			}
			Dbl_copytoptr(opnd1p1,opnd1p2,dstptr);
			return(NOEXCEPTION);
		}
	}

	if (Dbl_isinfinity_exponent(opnd2p1)) {
		if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) {
			if (Dbl_isnotnan(opnd3p1,opnd3p2)) {
				if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) {
					if (Is_invalidtrap_enabled())
						return(OPC_2E_INVALIDEXCEPTION);
					Set_invalidflag();
					Dbl_makequietnan(opnd2p1,opnd2p2);
					Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
					return(NOEXCEPTION);
				}

				if (Dbl_isinfinity(opnd3p1,opnd3p2) &&
				    (Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) {
					if (Is_invalidtrap_enabled())
				       		return(OPC_2E_INVALIDEXCEPTION);
				       	Set_invalidflag();
				       	Dbl_makequietnan(resultp1,resultp2);
					Dbl_copytoptr(resultp1,resultp2,dstptr);
					return(NOEXCEPTION);
				}

				Dbl_setinfinity_exponentmantissa(resultp1,resultp2);
				Dbl_copytoptr(resultp1,resultp2,dstptr);
				return(NOEXCEPTION);
			}
		}
		else {
			if (Dbl_isone_signaling(opnd2p1)) {
				
				if (Is_invalidtrap_enabled())
					return(OPC_2E_INVALIDEXCEPTION);
				
				Set_invalidflag();
				Dbl_set_quiet(opnd2p1);
			}
			else if (Dbl_is_signalingnan(opnd3p1)) {
			       	
			       	if (Is_invalidtrap_enabled())
				   		return(OPC_2E_INVALIDEXCEPTION);
			       	
			       	Set_invalidflag();
			       	Dbl_set_quiet(opnd3p1);
				Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
		       		return(NOEXCEPTION);
			}
			Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
			return(NOEXCEPTION);
		}
	}

	if (Dbl_isinfinity_exponent(opnd3p1)) {
		if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) {
			
			Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
			return(NOEXCEPTION);
		} else {
			if (Dbl_isone_signaling(opnd3p1)) {
				
				if (Is_invalidtrap_enabled())
					return(OPC_2E_INVALIDEXCEPTION);
				
				Set_invalidflag();
				Dbl_set_quiet(opnd3p1);
			}
			Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
			return(NOEXCEPTION);
		}
    	}

	if (Dbl_isnotzero_exponent(opnd1p1)) {
		
		Dbl_clear_signexponent_set_hidden(opnd1p1);
	}
	else {
		
		if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
			if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) {
				if (Is_rounding_mode(ROUNDMINUS)) {
					Dbl_or_signs(opnd3p1,resultp1);
				} else {
					Dbl_and_signs(opnd3p1,resultp1);
				}
			}
			else if (Dbl_iszero_exponent(opnd3p1) &&
			         Is_underflowtrap_enabled()) {
                    		
                    		sign_save = Dbl_signextendedsign(opnd3p1);
				result_exponent = 0;
                    		Dbl_leftshiftby1(opnd3p1,opnd3p2);
                    		Dbl_normalize(opnd3p1,opnd3p2,result_exponent);
                    		Dbl_set_sign(opnd3p1,sign_save);
                    		Dbl_setwrapped_exponent(opnd3p1,result_exponent,
							unfl);
                    		Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
                    		
                    		return(OPC_2E_UNDERFLOWEXCEPTION);
			}
			Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
			return(NOEXCEPTION);
		}
		
		Dbl_clear_signexponent(opnd1p1);
		Dbl_leftshiftby1(opnd1p1,opnd1p2);
		Dbl_normalize(opnd1p1,opnd1p2,mpy_exponent);
	}
	
	if (Dbl_isnotzero_exponent(opnd2p1)) {
		Dbl_clear_signexponent_set_hidden(opnd2p1);
	}
	else {
		
		if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) {
			if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) {
				if (Is_rounding_mode(ROUNDMINUS)) {
					Dbl_or_signs(opnd3p1,resultp1);
				} else {
					Dbl_and_signs(opnd3p1,resultp1);
				}
			}
			else if (Dbl_iszero_exponent(opnd3p1) &&
			    Is_underflowtrap_enabled()) {
                    		
                    		sign_save = Dbl_signextendedsign(opnd3p1);
				result_exponent = 0;
                    		Dbl_leftshiftby1(opnd3p1,opnd3p2);
                    		Dbl_normalize(opnd3p1,opnd3p2,result_exponent);
                    		Dbl_set_sign(opnd3p1,sign_save);
                    		Dbl_setwrapped_exponent(opnd3p1,result_exponent,
							unfl);
                    		Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
                    		
				return(OPC_2E_UNDERFLOWEXCEPTION);
			}
			Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
			return(NOEXCEPTION);
		}
		
		Dbl_clear_signexponent(opnd2p1);
		Dbl_leftshiftby1(opnd2p1,opnd2p2);
		Dbl_normalize(opnd2p1,opnd2p2,mpy_exponent);
	}

	

	Dblext_setzero(tmpresp1,tmpresp2,tmpresp3,tmpresp4);

 
	for (count = DBL_P-1; count >= 0; count -= 4) {
		Dblext_rightshiftby4(tmpresp1,tmpresp2,tmpresp3,tmpresp4);
		if (Dbit28p2(opnd1p2)) {
	 		
			Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, 
			 opnd2p1<<3 | opnd2p2>>29, opnd2p2<<3, 0, 0);
		}
		if (Dbit29p2(opnd1p2)) {
			Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4,
			 opnd2p1<<2 | opnd2p2>>30, opnd2p2<<2, 0, 0);
		}
		if (Dbit30p2(opnd1p2)) {
			Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4,
			 opnd2p1<<1 | opnd2p2>>31, opnd2p2<<1, 0, 0);
		}
		if (Dbit31p2(opnd1p2)) {
			Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4,
			 opnd2p1, opnd2p2, 0, 0);
		}
		Dbl_rightshiftby4(opnd1p1,opnd1p2);
	}
	if (Is_dexthiddenoverflow(tmpresp1)) {
		
		mpy_exponent++;
		Dblext_rightshiftby1(tmpresp1,tmpresp2,tmpresp3,tmpresp4);
	}

	Dblext_set_sign(tmpresp1,Dbl_sign(resultp1));


	add_exponent = Dbl_exponent(opnd3p1);

	if (add_exponent == 0) {
		
		if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) {
			
			result_exponent = mpy_exponent;
			Dblext_copy(tmpresp1,tmpresp2,tmpresp3,tmpresp4,
				resultp1,resultp2,resultp3,resultp4);
			sign_save = Dbl_signextendedsign(resultp1);
			goto round;
		}

		sign_save = Dbl_signextendedsign(opnd3p1);	
		Dbl_clear_signexponent(opnd3p1);
		Dbl_leftshiftby1(opnd3p1,opnd3p2);
		Dbl_normalize(opnd3p1,opnd3p2,add_exponent);
		Dbl_set_sign(opnd3p1,sign_save);	
	} else {
		Dbl_clear_exponent_set_hidden(opnd3p1);
	}
	Dbl_copyto_dblext(opnd3p1,opnd3p2,rightp1,rightp2,rightp3,rightp4);

	Dblext_xortointp1(tmpresp1,rightp1,save);

	Dblext_copytoint_exponentmantissap1(tmpresp1,signlessleft1);
	Dblext_copytoint_exponentmantissap1(rightp1,signlessright1);
	if (mpy_exponent < add_exponent || mpy_exponent == add_exponent &&
	    Dblext_ismagnitudeless(tmpresp2,rightp2,signlessleft1,signlessright1)){
		Dblext_xorfromintp1(save,rightp1,rightp1);
		Dblext_xorfromintp1(save,tmpresp1,tmpresp1);
		Dblext_swap_lower(tmpresp2,tmpresp3,tmpresp4,
			rightp2,rightp3,rightp4);
		
		diff_exponent = add_exponent - mpy_exponent;
		result_exponent = add_exponent;
	} else {
		
		diff_exponent = mpy_exponent - add_exponent;
		result_exponent = mpy_exponent;
	}
	

	if (diff_exponent > DBLEXT_THRESHOLD) {
		diff_exponent = DBLEXT_THRESHOLD;
	}

	
	Dblext_clear_sign(rightp1);
	Dblext_right_align(rightp1,rightp2,rightp3,rightp4,
		diff_exponent);
	
	
	if ((int)save < 0) {
		Dblext_subtract(tmpresp1,tmpresp2,tmpresp3,tmpresp4,
			rightp1,rightp2,rightp3,rightp4,
			resultp1,resultp2,resultp3,resultp4);
		sign_save = Dbl_signextendedsign(resultp1);
		if (Dbl_iszero_hidden(resultp1)) {
			
			Dblext_leftshiftby1(resultp1,resultp2,resultp3,
				resultp4);

			 if(Dblext_iszero(resultp1,resultp2,resultp3,resultp4)){
				
				if (Is_rounding_mode(ROUNDMINUS))
					Dbl_setone_sign(resultp1);
				Dbl_copytoptr(resultp1,resultp2,dstptr);
				return(NOEXCEPTION);
			}
			result_exponent--;

			
			if (Dbl_isone_hidden(resultp1)) {
				
				goto round;
			}

			
			while (Dbl_iszero_hiddenhigh7mantissa(resultp1)) {
				Dblext_leftshiftby8(resultp1,resultp2,resultp3,resultp4);
				result_exponent -= 8;
			}
			
			if (Dbl_iszero_hiddenhigh3mantissa(resultp1)) {
				Dblext_leftshiftby4(resultp1,resultp2,resultp3,resultp4);
				result_exponent -= 4;
			}
			jumpsize = Dbl_hiddenhigh3mantissa(resultp1);
			if (jumpsize <= 7) switch(jumpsize) {
			case 1:
				Dblext_leftshiftby3(resultp1,resultp2,resultp3,
					resultp4);
				result_exponent -= 3;
				break;
			case 2:
			case 3:
				Dblext_leftshiftby2(resultp1,resultp2,resultp3,
					resultp4);
				result_exponent -= 2;
				break;
			case 4:
			case 5:
			case 6:
			case 7:
				Dblext_leftshiftby1(resultp1,resultp2,resultp3,
					resultp4);
				result_exponent -= 1;
				break;
			}
		} 
	
	} 
	else {
		
		Dblext_addition(tmpresp1,tmpresp2,tmpresp3,tmpresp4,
			rightp1,rightp2,rightp3,rightp4,
			resultp1,resultp2,resultp3,resultp4);
		sign_save = Dbl_signextendedsign(resultp1);
		if (Dbl_isone_hiddenoverflow(resultp1)) {
	    		
	    		Dblext_arithrightshiftby1(resultp1,resultp2,resultp3,
				resultp4);
	    		result_exponent++;
		} 
	} 

  round:
	if (result_exponent <= 0 && !Is_underflowtrap_enabled()) {
		Dblext_denormalize(resultp1,resultp2,resultp3,resultp4,
			result_exponent,is_tiny);
	}
	Dbl_set_sign(resultp1,sign_save);
	if (Dblext_isnotzero_mantissap3(resultp3) || 
	    Dblext_isnotzero_mantissap4(resultp4)) {
		inexact = TRUE;
		switch(Rounding_mode()) {
		case ROUNDNEAREST: 
			if (Dblext_isone_highp3(resultp3)) {
				
				if (Dblext_isnotzero_low31p3(resultp3) ||
				    Dblext_isnotzero_mantissap4(resultp4) ||
				    Dblext_isone_lowp2(resultp2)) {
					Dbl_increment(resultp1,resultp2);
				}
			}
	    		break;

		case ROUNDPLUS:
	    		if (Dbl_iszero_sign(resultp1)) {
				
				Dbl_increment(resultp1,resultp2);
			}
			break;
	    
		case ROUNDMINUS:
	    		if (Dbl_isone_sign(resultp1)) {
				
				Dbl_increment(resultp1,resultp2);
			}
	    
		case ROUNDZERO:;
			
		} 
		if (Dbl_isone_hiddenoverflow(resultp1)) result_exponent++;
	}
	if (result_exponent >= DBL_INFINITY_EXPONENT) {
                
                if (Is_overflowtrap_enabled()) {
                        Dbl_setwrapped_exponent(resultp1,result_exponent,ovfl);
                        Dbl_copytoptr(resultp1,resultp2,dstptr);
                        if (inexact)
                            if (Is_inexacttrap_enabled())
                                return (OPC_2E_OVERFLOWEXCEPTION |
					OPC_2E_INEXACTEXCEPTION);
                            else Set_inexactflag();
                        return (OPC_2E_OVERFLOWEXCEPTION);
                }
                inexact = TRUE;
                Set_overflowflag();
                
                Dbl_setoverflow(resultp1,resultp2);

	} else if (result_exponent <= 0) {	
		if (Is_underflowtrap_enabled()) {
                	Dbl_setwrapped_exponent(resultp1,result_exponent,unfl);
			Dbl_copytoptr(resultp1,resultp2,dstptr);
                        if (inexact)
                            if (Is_inexacttrap_enabled())
                                return (OPC_2E_UNDERFLOWEXCEPTION |
					OPC_2E_INEXACTEXCEPTION);
                            else Set_inexactflag();
	    		return(OPC_2E_UNDERFLOWEXCEPTION);
		}
		else if (inexact && is_tiny) Set_underflowflag();
	}
	else Dbl_set_exponent(resultp1,result_exponent);
	Dbl_copytoptr(resultp1,resultp2,dstptr);
	if (inexact) 
		if (Is_inexacttrap_enabled()) return(OPC_2E_INEXACTEXCEPTION);
		else Set_inexactflag();
    	return(NOEXCEPTION);
}
Пример #10
0
/*ARGSUSED*/
int
sgl_fsqrt(sgl_floating_point *srcptr, sgl_floating_point *dstptr,
    unsigned int *status)
{
	register unsigned int src, result;
	register int src_exponent, newbit, sum;
	register int guardbit = false, even_exponent;

	src = *srcptr;
	/*
	 * check source operand for NaN or infinity
	 */
	if ((src_exponent = Sgl_exponent(src)) == SGL_INFINITY_EXPONENT) {
		/*
		 * is signaling NaN?
		 */
		if (Sgl_isone_signaling(src)) {
			/* trap if INVALIDTRAP enabled */
			if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
			/* make NaN quiet */
			Set_invalidflag();
			Sgl_set_quiet(src);
		}
		/*
		 * Return quiet NaN or positive infinity.
		 *  Fall thru to negative test if negative infinity.
		 */
		if (Sgl_iszero_sign(src) || Sgl_isnotzero_mantissa(src)) {
			*dstptr = src;
			return(NOEXCEPTION);
		}
	}

	/*
	 * check for zero source operand
	 */
	if (Sgl_iszero_exponentmantissa(src)) {
		*dstptr = src;
		return(NOEXCEPTION);
	}

	/*
	 * check for negative source operand
	 */
	if (Sgl_isone_sign(src)) {
		/* trap if INVALIDTRAP enabled */
		if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
		/* make NaN quiet */
		Set_invalidflag();
		Sgl_makequietnan(src);
		*dstptr = src;
		return(NOEXCEPTION);
	}

	/*
	 * Generate result
	 */
	if (src_exponent > 0) {
		even_exponent = Sgl_hidden(src);
		Sgl_clear_signexponent_set_hidden(src);
	}
	else {
		/* normalize operand */
		Sgl_clear_signexponent(src);
		src_exponent++;
		Sgl_normalize(src,src_exponent);
		even_exponent = src_exponent & 1;
	}
	if (even_exponent) {
		/* exponent is even */
		/* Add comment here.  Explain why odd exponent needs correction */
		Sgl_leftshiftby1(src);
	}
	/*
	 * Add comment here.  Explain following algorithm.
	 *
	 * Trust me, it works.
	 *
	 */
	Sgl_setzero(result);
	newbit = 1 << SGL_P;
	while (newbit && Sgl_isnotzero(src)) {
		Sgl_addition(result,newbit,sum);
		if(sum <= Sgl_all(src)) {
			/* update result */
			Sgl_addition(result,(newbit<<1),result);
			Sgl_subtract(src,sum,src);
		}
		Sgl_rightshiftby1(newbit);
		Sgl_leftshiftby1(src);
	}
	/* correct exponent for pre-shift */
	if (even_exponent) {
		Sgl_rightshiftby1(result);
	}

	/* check for inexact */
	if (Sgl_isnotzero(src)) {
		if (!even_exponent & Sgl_islessthan(result,src))
			Sgl_increment(result);
		guardbit = Sgl_lowmantissa(result);
		Sgl_rightshiftby1(result);

		/*  now round result  */
		switch (Rounding_mode()) {
		case ROUNDPLUS:
		     Sgl_increment(result);
		     break;
		case ROUNDNEAREST:
		     /* stickybit is always true, so guardbit
		      * is enough to determine rounding */
		     if (guardbit) {
			Sgl_increment(result);
		     }
		     break;
		}
		/* increment result exponent by 1 if mantissa overflowed */
		if (Sgl_isone_hiddenoverflow(result)) src_exponent+=2;

		if (Is_inexacttrap_enabled()) {
			Sgl_set_exponent(result,
			 ((src_exponent-SGL_BIAS)>>1)+SGL_BIAS);
			*dstptr = result;
			return(INEXACTEXCEPTION);
		}
		else Set_inexactflag();
	}