F-22
GUIDELINES FOR WRITING SIMD FLOATING-POINT EXCEPTION
case MULPS:
case MULSS:
// perform the multiplication
__asm {
// load input operands
fld DWORD PTR opd1; // may set the denormal status flag
fld DWORD PTR opd2; // may set the denormal status flag
fmulp st(1), st(0); // rounded to 53 bits, exact
// store result
fstp QWORD PTR dbl_res; // exact, will not set any flag
}
break;
case DIVPS:
case DIVSS:
// perform the division
__asm {
// load input operands
fld DWORD PTR opd1; // may set the denormal status flag
fld DWORD PTR opd2; // may set the denormal status flag
fdivp st(1), st(0); // rounded to 53 bits, may set the inexact
// status flag
// store result
fstp QWORD PTR dbl_res; // exact, will not set any flag
}
break;
default:
; // will never occur
}
// calculate result for the case an inexact trap has to be taken, or
// when no trap occurs (second IEEE rounding)
res = (float)dbl_res;
// may set P, U or O; may also involve denormalizing the result
// read status word
__asm {
fstsw WORD PTR sw;
}
// if inexact traps are enabled and result is inexact, take inexact trap
if (!(exc_env->exc_masks & PRECISION_MASK) &&
((sw & PRECISION_MASK) || (exc_env->ftz && result_tiny))) {
exc_env->status_flag_inexact = 1;
