int
sgl_fdiv (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_isinfinity(opnd2)) {
/*
* invalid since both operands
* are infinity
*/
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)) {
/*
* return zero
*/
Sgl_setzero_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);
}
/*
* check for division by zero
*/
if (Sgl_iszero_exponentmantissa(opnd2)) {
if (Sgl_iszero_exponentmantissa(opnd1)) {
/* invalid since both operands are zero */
if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
Set_invalidflag();
Sgl_makequietnan(result);
*dstptr = result;
return(NOEXCEPTION);
}
if (Is_divisionbyzerotrap_enabled())
return(DIVISIONBYZEROEXCEPTION);
Set_divisionbyzeroflag();
Sgl_setinfinity_exponentmantissa(result);
*dstptr = result;
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; want to normalize */
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 {
/* is denormalized; want to normalize */
Sgl_clear_signexponent(opnd2);
Sgl_leftshiftby1(opnd2);
while(Sgl_iszero_hiddenhigh7mantissa(opnd2)) {
Sgl_leftshiftby8(opnd2);
dest_exponent += 8;
}
if(Sgl_iszero_hiddenhigh3mantissa(opnd2)) {
Sgl_leftshiftby4(opnd2);
dest_exponent += 4;
}
while(Sgl_iszero_hidden(opnd2)) {
Sgl_leftshiftby1(opnd2);
dest_exponent += 1;
}
}
/* Divide the source mantissas */
/*
* A non_restoring divide algorithm is used.
*/
Sgl_subtract(opnd1,opnd2,opnd1);
Sgl_setzero(opnd3);
for (count=1;count<=SGL_P && Sgl_all(opnd1);count++) {
Sgl_leftshiftby1(opnd1);
Sgl_leftshiftby1(opnd3);
if (Sgl_iszero_sign(opnd1)) {
Sgl_setone_lowmantissa(opnd3);
Sgl_subtract(opnd1,opnd2,opnd1);
}
else Sgl_addition(opnd1,opnd2,opnd1);
}
if (count <= SGL_P) {
Sgl_leftshiftby1(opnd3);
Sgl_setone_lowmantissa(opnd3);
Sgl_leftshift(opnd3,SGL_P-count);
if (Sgl_iszero_hidden(opnd3)) {
Sgl_leftshiftby1(opnd3);
dest_exponent--;
}
}
else {
if (Sgl_iszero_hidden(opnd3)) {
/* need to get one more bit of result */
Sgl_leftshiftby1(opnd1);
Sgl_leftshiftby1(opnd3);
if (Sgl_iszero_sign(opnd1)) {
Sgl_setone_lowmantissa(opnd3);
Sgl_subtract(opnd1,opnd2,opnd1);
}
else Sgl_addition(opnd1,opnd2,opnd1);
dest_exponent--;
}
if (Sgl_iszero_sign(opnd1)) guardbit = TRUE;
stickybit = Sgl_all(opnd1);
}
inexact = guardbit | stickybit;
/*
* 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_mantissa(opnd3);
break;
case ROUNDMINUS:
if (Sgl_isone_sign(result))
Sgl_increment_mantissa(opnd3);
break;
case ROUNDNEAREST:
if (guardbit) {
if (stickybit || Sgl_isone_lowmantissa(opnd3))
Sgl_increment_mantissa(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);
}
Set_overflowflag();
/* set result to infinity or largest number */
Sgl_setoverflow(result);
inexact = TRUE;
}
/*
* 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 rounded 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
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);
}
/*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();
}