diff options
Diffstat (limited to 'target-i386/helper.c')
| -rw-r--r-- | target-i386/helper.c | 97 |
1 files changed, 70 insertions, 27 deletions
diff --git a/target-i386/helper.c b/target-i386/helper.c index aa136707e6..ef760adad3 100644 --- a/target-i386/helper.c +++ b/target-i386/helper.c @@ -3139,30 +3139,51 @@ void helper_fprem1(void) CPU86_LDouble dblq, fpsrcop, fptemp; CPU86_LDoubleU fpsrcop1, fptemp1; int expdif; - int q; + signed long long int q; + + if (isinf(ST0) || isnan(ST0) || isnan(ST1) || (ST1 == 0.0)) { + ST0 = 0.0 / 0.0; /* NaN */ + env->fpus &= (~0x4700); /* (C3,C2,C1,C0) <-- 0000 */ + return; + } fpsrcop = ST0; fptemp = ST1; fpsrcop1.d = fpsrcop; fptemp1.d = fptemp; expdif = EXPD(fpsrcop1) - EXPD(fptemp1); + + if (expdif < 0) { + /* optimisation? taken from the AMD docs */ + env->fpus &= (~0x4700); /* (C3,C2,C1,C0) <-- 0000 */ + /* ST0 is unchanged */ + return; + } + if (expdif < 53) { dblq = fpsrcop / fptemp; - dblq = (dblq < 0.0)? ceil(dblq): floor(dblq); - ST0 = fpsrcop - fptemp*dblq; - q = (int)dblq; /* cutting off top bits is assumed here */ + /* round dblq towards nearest integer */ + dblq = rint(dblq); + ST0 = fpsrcop - fptemp * dblq; + + /* convert dblq to q by truncating towards zero */ + if (dblq < 0.0) + q = (signed long long int)(-dblq); + else + q = (signed long long int)dblq; + env->fpus &= (~0x4700); /* (C3,C2,C1,C0) <-- 0000 */ - /* (C0,C1,C3) <-- (q2,q1,q0) */ - env->fpus |= (q&0x4) << 6; /* (C0) <-- q2 */ - env->fpus |= (q&0x2) << 8; /* (C1) <-- q1 */ - env->fpus |= (q&0x1) << 14; /* (C3) <-- q0 */ + /* (C0,C3,C1) <-- (q2,q1,q0) */ + env->fpus |= (q & 0x4) << (8 - 2); /* (C0) <-- q2 */ + env->fpus |= (q & 0x2) << (14 - 1); /* (C3) <-- q1 */ + env->fpus |= (q & 0x1) << (9 - 0); /* (C1) <-- q0 */ } else { env->fpus |= 0x400; /* C2 <-- 1 */ - fptemp = pow(2.0, expdif-50); + fptemp = pow(2.0, expdif - 50); fpsrcop = (ST0 / ST1) / fptemp; - /* fpsrcop = integer obtained by rounding to the nearest */ - fpsrcop = (fpsrcop-floor(fpsrcop) < ceil(fpsrcop)-fpsrcop)? - floor(fpsrcop): ceil(fpsrcop); + /* fpsrcop = integer obtained by chopping */ + fpsrcop = (fpsrcop < 0.0) ? + -(floor(fabs(fpsrcop))) : floor(fpsrcop); ST0 -= (ST1 * fpsrcop * fptemp); } } @@ -3172,30 +3193,52 @@ void helper_fprem(void) CPU86_LDouble dblq, fpsrcop, fptemp; CPU86_LDoubleU fpsrcop1, fptemp1; int expdif; - int q; - - fpsrcop = ST0; - fptemp = ST1; + signed long long int q; + + if (isinf(ST0) || isnan(ST0) || isnan(ST1) || (ST1 == 0.0)) { + ST0 = 0.0 / 0.0; /* NaN */ + env->fpus &= (~0x4700); /* (C3,C2,C1,C0) <-- 0000 */ + return; + } + + fpsrcop = (CPU86_LDouble)ST0; + fptemp = (CPU86_LDouble)ST1; fpsrcop1.d = fpsrcop; fptemp1.d = fptemp; expdif = EXPD(fpsrcop1) - EXPD(fptemp1); + + if (expdif < 0) { + /* optimisation? taken from the AMD docs */ + env->fpus &= (~0x4700); /* (C3,C2,C1,C0) <-- 0000 */ + /* ST0 is unchanged */ + return; + } + if ( expdif < 53 ) { - dblq = fpsrcop / fptemp; - dblq = (dblq < 0.0)? ceil(dblq): floor(dblq); - ST0 = fpsrcop - fptemp*dblq; - q = (int)dblq; /* cutting off top bits is assumed here */ + dblq = fpsrcop/*ST0*/ / fptemp/*ST1*/; + /* round dblq towards zero */ + dblq = (dblq < 0.0) ? ceil(dblq) : floor(dblq); + ST0 = fpsrcop/*ST0*/ - fptemp * dblq; + + /* convert dblq to q by truncating towards zero */ + if (dblq < 0.0) + q = (signed long long int)(-dblq); + else + q = (signed long long int)dblq; + env->fpus &= (~0x4700); /* (C3,C2,C1,C0) <-- 0000 */ - /* (C0,C1,C3) <-- (q2,q1,q0) */ - env->fpus |= (q&0x4) << 6; /* (C0) <-- q2 */ - env->fpus |= (q&0x2) << 8; /* (C1) <-- q1 */ - env->fpus |= (q&0x1) << 14; /* (C3) <-- q0 */ + /* (C0,C3,C1) <-- (q2,q1,q0) */ + env->fpus |= (q & 0x4) << (8 - 2); /* (C0) <-- q2 */ + env->fpus |= (q & 0x2) << (14 - 1); /* (C3) <-- q1 */ + env->fpus |= (q & 0x1) << (9 - 0); /* (C1) <-- q0 */ } else { + int N = 32 + (expdif % 32); /* as per AMD docs */ env->fpus |= 0x400; /* C2 <-- 1 */ - fptemp = pow(2.0, expdif-50); + fptemp = pow(2.0, (double)(expdif - N)); fpsrcop = (ST0 / ST1) / fptemp; /* fpsrcop = integer obtained by chopping */ - fpsrcop = (fpsrcop < 0.0)? - -(floor(fabs(fpsrcop))): floor(fpsrcop); + fpsrcop = (fpsrcop < 0.0) ? + -(floor(fabs(fpsrcop))) : floor(fpsrcop); ST0 -= (ST1 * fpsrcop * fptemp); } } |