Example #1
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);
}
Example #2
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);
}
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);
}
Example #4
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);
}
Example #5
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);
}
Example #6
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);
}