diff options
Diffstat (limited to 'target/m68k')
| -rw-r--r-- | target/m68k/cpu.c | 35 | ||||
| -rw-r--r-- | target/m68k/fpu_helper.c | 2 | ||||
| -rw-r--r-- | target/m68k/softfloat.c | 47 |
3 files changed, 52 insertions, 32 deletions
diff --git a/target/m68k/cpu.c b/target/m68k/cpu.c index 41dfdf5804..2617d8f6ed 100644 --- a/target/m68k/cpu.c +++ b/target/m68k/cpu.c @@ -107,6 +107,41 @@ static void m68k_cpu_reset_hold(Object *obj, ResetType type) set_float_2nan_prop_rule(float_2nan_prop_ab, &env->fp_status); /* Default NaN: sign bit clear, all frac bits set */ set_float_default_nan_pattern(0b01111111, &env->fp_status); + /* + * m68k-specific floatx80 behaviour: + * * default Infinity values have a zero Integer bit + * * input Infinities may have the Integer bit either 0 or 1 + * * pseudo-denormals supported for input and output + * * don't raise Invalid for pseudo-NaN/pseudo-Inf/Unnormal + * + * With m68k, the explicit integer bit can be zero in the case of: + * - zeros (exp == 0, mantissa == 0) + * - denormalized numbers (exp == 0, mantissa != 0) + * - unnormalized numbers (exp != 0, exp < 0x7FFF) + * - infinities (exp == 0x7FFF, mantissa == 0) + * - not-a-numbers (exp == 0x7FFF, mantissa != 0) + * + * For infinities and NaNs, the explicit integer bit can be either one or + * zero. + * + * The IEEE 754 standard does not define a zero integer bit. Such a number + * is an unnormalized number. Hardware does not directly support + * denormalized and unnormalized numbers, but implicitly supports them by + * trapping them as unimplemented data types, allowing efficient conversion + * in software. + * + * See "M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL", + * "1.6 FLOATING-POINT DATA TYPES" + * + * Note though that QEMU's fp emulation does directly handle both + * denormal and unnormal values, and does not trap to guest software. + */ + set_floatx80_behaviour(floatx80_default_inf_int_bit_is_zero | + floatx80_pseudo_inf_valid | + floatx80_pseudo_nan_valid | + floatx80_unnormal_valid | + floatx80_pseudo_denormal_valid, + &env->fp_status); nan = floatx80_default_nan(&env->fp_status); for (i = 0; i < 8; i++) { diff --git a/target/m68k/fpu_helper.c b/target/m68k/fpu_helper.c index 339b73ad7d..eb1cb8c687 100644 --- a/target/m68k/fpu_helper.c +++ b/target/m68k/fpu_helper.c @@ -455,7 +455,7 @@ void HELPER(ftst)(CPUM68KState *env, FPReg *val) if (floatx80_is_any_nan(val->d)) { cc |= FPSR_CC_A; - } else if (floatx80_is_infinity(val->d)) { + } else if (floatx80_is_infinity(val->d, &env->fp_status)) { cc |= FPSR_CC_I; } else if (floatx80_is_zero(val->d)) { cc |= FPSR_CC_Z; diff --git a/target/m68k/softfloat.c b/target/m68k/softfloat.c index 02dcc03d15..d1f150e641 100644 --- a/target/m68k/softfloat.c +++ b/target/m68k/softfloat.c @@ -142,8 +142,7 @@ floatx80 floatx80_scale(floatx80 a, floatx80 b, float_status *status) if ((uint64_t) (aSig << 1)) { return propagateFloatx80NaN(a, b, status); } - return packFloatx80(aSign, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(aSign, status); } if (aExp == 0) { if (aSig == 0) { @@ -245,7 +244,7 @@ floatx80 floatx80_lognp1(floatx80 a, float_status *status) float_raise(float_flag_invalid, status); return floatx80_default_nan(status); } - return packFloatx80(0, floatx80_infinity.high, floatx80_infinity.low); + return floatx80_default_inf(0, status); } if (aExp == 0 && aSig == 0) { @@ -255,8 +254,7 @@ floatx80 floatx80_lognp1(floatx80 a, float_status *status) if (aSign && aExp >= one_exp) { if (aExp == one_exp && aSig == one_sig) { float_raise(float_flag_divbyzero, status); - return packFloatx80(aSign, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(aSign, status); } float_raise(float_flag_invalid, status); return floatx80_default_nan(status); @@ -442,8 +440,7 @@ floatx80 floatx80_logn(floatx80 a, float_status *status) propagateFloatx80NaNOneArg(a, status); } if (aSign == 0) { - return packFloatx80(0, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(0, status); } } @@ -452,8 +449,7 @@ floatx80 floatx80_logn(floatx80 a, float_status *status) if (aExp == 0) { if (aSig == 0) { /* zero */ float_raise(float_flag_divbyzero, status); - return packFloatx80(1, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(1, status); } if ((aSig & one_sig) == 0) { /* denormal */ normalizeFloatx80Subnormal(aSig, &aExp, &aSig); @@ -610,15 +606,13 @@ floatx80 floatx80_log10(floatx80 a, float_status *status) propagateFloatx80NaNOneArg(a, status); } if (aSign == 0) { - return packFloatx80(0, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(0, status); } } if (aExp == 0 && aSig == 0) { float_raise(float_flag_divbyzero, status); - return packFloatx80(1, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(1, status); } if (aSign) { @@ -668,16 +662,14 @@ floatx80 floatx80_log2(floatx80 a, float_status *status) propagateFloatx80NaNOneArg(a, status); } if (aSign == 0) { - return packFloatx80(0, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(0, status); } } if (aExp == 0) { if (aSig == 0) { float_raise(float_flag_divbyzero, status); - return packFloatx80(1, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(1, status); } normalizeFloatx80Subnormal(aSig, &aExp, &aSig); } @@ -740,8 +732,7 @@ floatx80 floatx80_etox(floatx80 a, float_status *status) if (aSign) { return packFloatx80(0, 0, 0); } - return packFloatx80(0, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(0, status); } if (aExp == 0 && aSig == 0) { @@ -924,8 +915,7 @@ floatx80 floatx80_twotox(floatx80 a, float_status *status) if (aSign) { return packFloatx80(0, 0, 0); } - return packFloatx80(0, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(0, status); } if (aExp == 0 && aSig == 0) { @@ -1075,8 +1065,7 @@ floatx80 floatx80_tentox(floatx80 a, float_status *status) if (aSign) { return packFloatx80(0, 0, 0); } - return packFloatx80(0, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(0, status); } if (aExp == 0 && aSig == 0) { @@ -2260,8 +2249,7 @@ floatx80 floatx80_atanh(floatx80 a, float_status *status) if (compact >= 0x3FFF8000) { /* |X| >= 1 */ if (aExp == one_exp && aSig == one_sig) { /* |X| == 1 */ float_raise(float_flag_divbyzero, status); - return packFloatx80(aSign, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(aSign, status); } else { /* |X| > 1 */ float_raise(float_flag_invalid, status); return floatx80_default_nan(status); @@ -2320,8 +2308,7 @@ floatx80 floatx80_etoxm1(floatx80 a, float_status *status) if (aSign) { return packFloatx80(aSign, one_exp, one_sig); } - return packFloatx80(0, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(0, status); } if (aExp == 0 && aSig == 0) { @@ -2687,8 +2674,7 @@ floatx80 floatx80_sinh(floatx80 a, float_status *status) if ((uint64_t) (aSig << 1)) { return propagateFloatx80NaNOneArg(a, status); } - return packFloatx80(aSign, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(aSign, status); } if (aExp == 0 && aSig == 0) { @@ -2774,8 +2760,7 @@ floatx80 floatx80_cosh(floatx80 a, float_status *status) if ((uint64_t) (aSig << 1)) { return propagateFloatx80NaNOneArg(a, status); } - return packFloatx80(0, floatx80_infinity.high, - floatx80_infinity.low); + return floatx80_default_inf(0, status); } if (aExp == 0 && aSig == 0) { |