From 03385dfdaaa2dc31bbd07d13244a6b037bfab4cc Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Thu, 10 May 2018 14:48:17 -0700 Subject: [PATCH] fpu/softfloat: Specialize on snan_bit_is_one MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Only MIPS requires snan_bit_is_one to be variable. While we are specializing softfloat behaviour, allow other targets to eliminate this runtime check. Cc: Aurelien Jarno Cc: Yongbok Kim Cc: David Gibson Cc: Alexander Graf Cc: Guan Xuetao Tested-by: Alex Bennée Reviewed-by: Alex Bennée Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson --- fpu/softfloat-specialize.h | 68 +++++++++++++++++++++++++++---------------- include/fpu/softfloat-types.h | 1 + target/hppa/cpu.c | 1 - target/ppc/fpu_helper.c | 1 - target/sh4/cpu.c | 1 - target/unicore32/cpu.c | 2 -- 6 files changed, 44 insertions(+), 30 deletions(-) diff --git a/fpu/softfloat-specialize.h b/fpu/softfloat-specialize.h index d7033b7757..d1e06da75b 100644 --- a/fpu/softfloat-specialize.h +++ b/fpu/softfloat-specialize.h @@ -79,13 +79,31 @@ this code that are retained. * version 2 or later. See the COPYING file in the top-level directory. */ -#if defined(TARGET_XTENSA) /* Define for architectures which deviate from IEEE in not supporting * signaling NaNs (so all NaNs are treated as quiet). */ +#if defined(TARGET_XTENSA) #define NO_SIGNALING_NANS 1 #endif +/* Define how the architecture discriminates signaling NaNs. + * This done with the most significant bit of the fraction. + * In IEEE 754-1985 this was implementation defined, but in IEEE 754-2008 + * the msb must be zero. MIPS is (so far) unique in supporting both the + * 2008 revision and backward compatibility with their original choice. + * Thus for MIPS we must make the choice at runtime. + */ +static inline flag snan_bit_is_one(float_status *status) +{ +#if defined(TARGET_MIPS) + return status->snan_bit_is_one; +#elif defined(TARGET_HPPA) || defined(TARGET_UNICORE32) || defined(TARGET_SH4) + return 1; +#else + return 0; +#endif +} + /*---------------------------------------------------------------------------- | For the deconstructed floating-point with fraction FRAC, return true | if the fraction represents a signalling NaN; otherwise false. @@ -97,7 +115,7 @@ static bool parts_is_snan_frac(uint64_t frac, float_status *status) return false; #else flag msb = extract64(frac, DECOMPOSED_BINARY_POINT - 1, 1); - return msb == status->snan_bit_is_one; + return msb == snan_bit_is_one(status); #endif } @@ -118,7 +136,7 @@ static FloatParts parts_default_nan(float_status *status) #elif defined(TARGET_HPPA) frac = 1ULL << (DECOMPOSED_BINARY_POINT - 2); #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { frac = (1ULL << (DECOMPOSED_BINARY_POINT - 1)) - 1; } else { #if defined(TARGET_MIPS) @@ -151,7 +169,7 @@ static FloatParts parts_silence_nan(FloatParts a, float_status *status) a.frac &= ~(1ULL << (DECOMPOSED_BINARY_POINT - 1)); a.frac |= 1ULL << (DECOMPOSED_BINARY_POINT - 2); #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return parts_default_nan(status); } else { a.frac |= 1ULL << (DECOMPOSED_BINARY_POINT - 1); @@ -169,7 +187,7 @@ float16 float16_default_nan(float_status *status) #if defined(TARGET_ARM) return const_float16(0x7E00); #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return const_float16(0x7DFF); } else { #if defined(TARGET_MIPS) @@ -195,7 +213,7 @@ float32 float32_default_nan(float_status *status) #elif defined(TARGET_HPPA) return const_float32(0x7FA00000); #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return const_float32(0x7FBFFFFF); } else { #if defined(TARGET_MIPS) @@ -220,7 +238,7 @@ float64 float64_default_nan(float_status *status) #elif defined(TARGET_HPPA) return const_float64(LIT64(0x7FF4000000000000)); #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return const_float64(LIT64(0x7FF7FFFFFFFFFFFF)); } else { #if defined(TARGET_MIPS) @@ -242,7 +260,7 @@ floatx80 floatx80_default_nan(float_status *status) r.low = LIT64(0xFFFFFFFFFFFFFFFF); r.high = 0x7FFF; #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { r.low = LIT64(0xBFFFFFFFFFFFFFFF); r.high = 0x7FFF; } else { @@ -274,7 +292,7 @@ float128 float128_default_nan(float_status *status) { float128 r; - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { r.low = LIT64(0xFFFFFFFFFFFFFFFF); r.high = LIT64(0x7FFF7FFFFFFFFFFF); } else { @@ -319,7 +337,7 @@ int float16_is_quiet_nan(float16 a_, float_status *status) return float16_is_any_nan(a_); #else uint16_t a = float16_val(a_); - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return (((a >> 9) & 0x3F) == 0x3E) && (a & 0x1FF); } else { return ((a & ~0x8000) >= 0x7C80); @@ -338,7 +356,7 @@ int float16_is_signaling_nan(float16 a_, float_status *status) return 0; #else uint16_t a = float16_val(a_); - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return ((a & ~0x8000) >= 0x7C80); } else { return (((a >> 9) & 0x3F) == 0x3E) && (a & 0x1FF); @@ -356,7 +374,7 @@ float16 float16_silence_nan(float16 a, float_status *status) #ifdef NO_SIGNALING_NANS g_assert_not_reached(); #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return float16_default_nan(status); } else { return a | (1 << 9); @@ -375,7 +393,7 @@ int float32_is_quiet_nan(float32 a_, float_status *status) return float32_is_any_nan(a_); #else uint32_t a = float32_val(a_); - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return (((a >> 22) & 0x1FF) == 0x1FE) && (a & 0x003FFFFF); } else { return ((uint32_t)(a << 1) >= 0xFF800000); @@ -394,7 +412,7 @@ int float32_is_signaling_nan(float32 a_, float_status *status) return 0; #else uint32_t a = float32_val(a_); - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return ((uint32_t)(a << 1) >= 0xFF800000); } else { return (((a >> 22) & 0x1FF) == 0x1FE) && (a & 0x003FFFFF); @@ -412,7 +430,7 @@ float32 float32_silence_nan(float32 a, float_status *status) #ifdef NO_SIGNALING_NANS g_assert_not_reached(); #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { # ifdef TARGET_HPPA a &= ~0x00400000; a |= 0x00200000; @@ -651,7 +669,7 @@ static int pickNaNMulAdd(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN, return 3; } - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { /* Prefer sNaN over qNaN, in the a, b, c order. */ if (aIsSNaN) { return 0; @@ -786,7 +804,7 @@ int float64_is_quiet_nan(float64 a_, float_status *status) return float64_is_any_nan(a_); #else uint64_t a = float64_val(a_); - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return (((a >> 51) & 0xFFF) == 0xFFE) && (a & 0x0007FFFFFFFFFFFFULL); } else { @@ -806,7 +824,7 @@ int float64_is_signaling_nan(float64 a_, float_status *status) return 0; #else uint64_t a = float64_val(a_); - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return ((a << 1) >= 0xFFF0000000000000ULL); } else { return (((a >> 51) & 0xFFF) == 0xFFE) @@ -825,7 +843,7 @@ float64 float64_silence_nan(float64 a, float_status *status) #ifdef NO_SIGNALING_NANS g_assert_not_reached(); #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { # ifdef TARGET_HPPA a &= ~0x0008000000000000ULL; a |= 0x0004000000000000ULL; @@ -942,7 +960,7 @@ int floatx80_is_quiet_nan(floatx80 a, float_status *status) #ifdef NO_SIGNALING_NANS return floatx80_is_any_nan(a); #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { uint64_t aLow; aLow = a.low & ~0x4000000000000000ULL; @@ -967,7 +985,7 @@ int floatx80_is_signaling_nan(floatx80 a, float_status *status) #ifdef NO_SIGNALING_NANS return 0; #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return ((a.high & 0x7FFF) == 0x7FFF) && ((a.low << 1) >= 0x8000000000000000ULL); } else { @@ -991,7 +1009,7 @@ floatx80 floatx80_silence_nan(floatx80 a, float_status *status) #ifdef NO_SIGNALING_NANS g_assert_not_reached(); #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return floatx80_default_nan(status); } else { a.low |= LIT64(0xC000000000000000); @@ -1105,7 +1123,7 @@ int float128_is_quiet_nan(float128 a, float_status *status) #ifdef NO_SIGNALING_NANS return float128_is_any_nan(a); #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return (((a.high >> 47) & 0xFFFF) == 0xFFFE) && (a.low || (a.high & 0x00007FFFFFFFFFFFULL)); } else { @@ -1125,7 +1143,7 @@ int float128_is_signaling_nan(float128 a, float_status *status) #ifdef NO_SIGNALING_NANS return 0; #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return ((a.high << 1) >= 0xFFFF000000000000ULL) && (a.low || (a.high & 0x0000FFFFFFFFFFFFULL)); } else { @@ -1145,7 +1163,7 @@ float128 float128_silence_nan(float128 a, float_status *status) #ifdef NO_SIGNALING_NANS g_assert_not_reached(); #else - if (status->snan_bit_is_one) { + if (snan_bit_is_one(status)) { return float128_default_nan(status); } else { a.high |= LIT64(0x0000800000000000); diff --git a/include/fpu/softfloat-types.h b/include/fpu/softfloat-types.h index 4e378cb612..2aae6a89b1 100644 --- a/include/fpu/softfloat-types.h +++ b/include/fpu/softfloat-types.h @@ -173,6 +173,7 @@ typedef struct float_status { /* should denormalised inputs go to zero and set the input_denormal flag? */ flag flush_inputs_to_zero; flag default_nan_mode; + /* not always used -- see snan_bit_is_one() in softfloat-specialize.h */ flag snan_bit_is_one; } float_status; diff --git a/target/hppa/cpu.c b/target/hppa/cpu.c index c261b6b090..00bf444620 100644 --- a/target/hppa/cpu.c +++ b/target/hppa/cpu.c @@ -141,7 +141,6 @@ static void hppa_cpu_initfn(Object *obj) cs->env_ptr = env; cs->exception_index = -1; cpu_hppa_loaded_fr0(env); - set_snan_bit_is_one(true, &env->fp_status); cpu_hppa_put_psw(env, PSW_W); } diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c index 9ae418a577..d31a933cbb 100644 --- a/target/ppc/fpu_helper.c +++ b/target/ppc/fpu_helper.c @@ -3382,7 +3382,6 @@ void helper_xssqrtqp(CPUPPCState *env, uint32_t opcode) xt.f128 = xb.f128; } else if (float128_is_neg(xb.f128) && !float128_is_zero(xb.f128)) { float_invalid_op_excp(env, POWERPC_EXCP_FP_VXSQRT, 1); - set_snan_bit_is_one(0, &env->fp_status); xt.f128 = float128_default_nan(&env->fp_status); } } diff --git a/target/sh4/cpu.c b/target/sh4/cpu.c index 541ffc2d97..b9f393b7c7 100644 --- a/target/sh4/cpu.c +++ b/target/sh4/cpu.c @@ -71,7 +71,6 @@ static void superh_cpu_reset(CPUState *s) set_flush_to_zero(1, &env->fp_status); #endif set_default_nan_mode(1, &env->fp_status); - set_snan_bit_is_one(1, &env->fp_status); } static void superh_cpu_disas_set_info(CPUState *cpu, disassemble_info *info) diff --git a/target/unicore32/cpu.c b/target/unicore32/cpu.c index 29d160a88d..68f978d80b 100644 --- a/target/unicore32/cpu.c +++ b/target/unicore32/cpu.c @@ -70,7 +70,6 @@ static void unicore_ii_cpu_initfn(Object *obj) set_feature(env, UC32_HWCAP_CMOV); set_feature(env, UC32_HWCAP_UCF64); - set_snan_bit_is_one(1, &env->ucf64.fp_status); } static void uc32_any_cpu_initfn(Object *obj) @@ -83,7 +82,6 @@ static void uc32_any_cpu_initfn(Object *obj) set_feature(env, UC32_HWCAP_CMOV); set_feature(env, UC32_HWCAP_UCF64); - set_snan_bit_is_one(1, &env->ucf64.fp_status); } static void uc32_cpu_realizefn(DeviceState *dev, Error **errp) -- 2.11.4.GIT