The x87 fprem emulation is currently based around conversion to double, which is inherently unsuitable for a good emulation of any floatx80 operation. Reimplement using the soft-float floatx80 remainder operations.
Signed-off-by: Joseph Myers <jos...@codesourcery.com> --- target/i386/fpu_helper.c | 58 +--------------------------------------- 1 file changed, 1 insertion(+), 57 deletions(-) diff --git a/target/i386/fpu_helper.c b/target/i386/fpu_helper.c index bab35e00a0..d2fc2c1dde 100644 --- a/target/i386/fpu_helper.c +++ b/target/i386/fpu_helper.c @@ -989,63 +989,7 @@ void helper_fprem1(CPUX86State *env) void helper_fprem(CPUX86State *env) { - double st0, st1, dblq, fpsrcop, fptemp; - CPU_LDoubleU fpsrcop1, fptemp1; - int expdif; - signed long long int q; - - st0 = floatx80_to_double(env, ST0); - st1 = floatx80_to_double(env, ST1); - - if (isinf(st0) || isnan(st0) || isnan(st1) || (st1 == 0.0)) { - ST0 = double_to_floatx80(env, 0.0 / 0.0); /* NaN */ - env->fpus &= ~0x4700; /* (C3,C2,C1,C0) <-- 0000 */ - return; - } - - fpsrcop = st0; - fptemp = st1; - fpsrcop1.d = ST0; - fptemp1.d = ST1; - 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; /* ST0 / ST1 */ - /* round dblq towards zero */ - dblq = (dblq < 0.0) ? ceil(dblq) : floor(dblq); - st0 = fpsrcop - fptemp * dblq; /* fpsrcop is ST0 */ - - /* 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,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, (double)(expdif - N)); - fpsrcop = (st0 / st1) / fptemp; - /* fpsrcop = integer obtained by chopping */ - fpsrcop = (fpsrcop < 0.0) ? - -(floor(fabs(fpsrcop))) : floor(fpsrcop); - st0 -= (st1 * fpsrcop * fptemp); - } - ST0 = double_to_floatx80(env, st0); + helper_fprem_common(env, true); } void helper_fyl2xp1(CPUX86State *env) -- 2.17.1 -- Joseph S. Myers jos...@codesourcery.com