From b240c9c497b9880ac0ba29465907d5ebecd48083 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 4 May 2020 16:57:21 -0700 Subject: [PATCH] softfloat: Use post test for floatN_mul MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The existing f{32,64}_addsub_post test, which checks for zero inputs, is identical to f{32,64}_mul_fast_test. Which means we can eliminate the fast_test/fast_op hooks in favor of reusing the same post hook. This means we have one fewer test along the fast path for multiply. Tested-by: Alex Bennée Reviewed-by: Alex Bennée Signed-off-by: Richard Henderson --- fpu/softfloat.c | 65 +++++++++++-------------------------------------- 1 file changed, 14 insertions(+), 51 deletions(-) diff --git a/fpu/softfloat.c b/fpu/softfloat.c index a362bf89ca..5fb4ef75bb 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -339,12 +339,10 @@ static inline bool f64_is_inf(union_float64 a) return float64_is_infinity(a.s); } -/* Note: @fast_test and @post can be NULL */ static inline float32 float32_gen2(float32 xa, float32 xb, float_status *s, hard_f32_op2_fn hard, soft_f32_op2_fn soft, - f32_check_fn pre, f32_check_fn post, - f32_check_fn fast_test, soft_f32_op2_fn fast_op) + f32_check_fn pre, f32_check_fn post) { union_float32 ua, ub, ur; @@ -359,17 +357,12 @@ float32_gen2(float32 xa, float32 xb, float_status *s, if (unlikely(!pre(ua, ub))) { goto soft; } - if (fast_test && fast_test(ua, ub)) { - return fast_op(ua.s, ub.s, s); - } ur.h = hard(ua.h, ub.h); if (unlikely(f32_is_inf(ur))) { s->float_exception_flags |= float_flag_overflow; - } else if (unlikely(fabsf(ur.h) <= FLT_MIN)) { - if (post == NULL || post(ua, ub)) { - goto soft; - } + } else if (unlikely(fabsf(ur.h) <= FLT_MIN) && post(ua, ub)) { + goto soft; } return ur.s; @@ -380,8 +373,7 @@ float32_gen2(float32 xa, float32 xb, float_status *s, static inline float64 float64_gen2(float64 xa, float64 xb, float_status *s, hard_f64_op2_fn hard, soft_f64_op2_fn soft, - f64_check_fn pre, f64_check_fn post, - f64_check_fn fast_test, soft_f64_op2_fn fast_op) + f64_check_fn pre, f64_check_fn post) { union_float64 ua, ub, ur; @@ -396,17 +388,12 @@ float64_gen2(float64 xa, float64 xb, float_status *s, if (unlikely(!pre(ua, ub))) { goto soft; } - if (fast_test && fast_test(ua, ub)) { - return fast_op(ua.s, ub.s, s); - } ur.h = hard(ua.h, ub.h); if (unlikely(f64_is_inf(ur))) { s->float_exception_flags |= float_flag_overflow; - } else if (unlikely(fabs(ur.h) <= DBL_MIN)) { - if (post == NULL || post(ua, ub)) { - goto soft; - } + } else if (unlikely(fabs(ur.h) <= DBL_MIN) && post(ua, ub)) { + goto soft; } return ur.s; @@ -1115,7 +1102,7 @@ static double hard_f64_sub(double a, double b) return a - b; } -static bool f32_addsub_post(union_float32 a, union_float32 b) +static bool f32_addsubmul_post(union_float32 a, union_float32 b) { if (QEMU_HARDFLOAT_2F32_USE_FP) { return !(fpclassify(a.h) == FP_ZERO && fpclassify(b.h) == FP_ZERO); @@ -1123,7 +1110,7 @@ static bool f32_addsub_post(union_float32 a, union_float32 b) return !(float32_is_zero(a.s) && float32_is_zero(b.s)); } -static bool f64_addsub_post(union_float64 a, union_float64 b) +static bool f64_addsubmul_post(union_float64 a, union_float64 b) { if (QEMU_HARDFLOAT_2F64_USE_FP) { return !(fpclassify(a.h) == FP_ZERO && fpclassify(b.h) == FP_ZERO); @@ -1136,14 +1123,14 @@ static float32 float32_addsub(float32 a, float32 b, float_status *s, hard_f32_op2_fn hard, soft_f32_op2_fn soft) { return float32_gen2(a, b, s, hard, soft, - f32_is_zon2, f32_addsub_post, NULL, NULL); + f32_is_zon2, f32_addsubmul_post); } static float64 float64_addsub(float64 a, float64 b, float_status *s, hard_f64_op2_fn hard, soft_f64_op2_fn soft) { return float64_gen2(a, b, s, hard, soft, - f64_is_zon2, f64_addsub_post, NULL, NULL); + f64_is_zon2, f64_addsubmul_post); } float32 QEMU_FLATTEN @@ -1258,42 +1245,18 @@ static double hard_f64_mul(double a, double b) return a * b; } -static bool f32_mul_fast_test(union_float32 a, union_float32 b) -{ - return float32_is_zero(a.s) || float32_is_zero(b.s); -} - -static bool f64_mul_fast_test(union_float64 a, union_float64 b) -{ - return float64_is_zero(a.s) || float64_is_zero(b.s); -} - -static float32 f32_mul_fast_op(float32 a, float32 b, float_status *s) -{ - bool signbit = float32_is_neg(a) ^ float32_is_neg(b); - - return float32_set_sign(float32_zero, signbit); -} - -static float64 f64_mul_fast_op(float64 a, float64 b, float_status *s) -{ - bool signbit = float64_is_neg(a) ^ float64_is_neg(b); - - return float64_set_sign(float64_zero, signbit); -} - float32 QEMU_FLATTEN float32_mul(float32 a, float32 b, float_status *s) { return float32_gen2(a, b, s, hard_f32_mul, soft_f32_mul, - f32_is_zon2, NULL, f32_mul_fast_test, f32_mul_fast_op); + f32_is_zon2, f32_addsubmul_post); } float64 QEMU_FLATTEN float64_mul(float64 a, float64 b, float_status *s) { return float64_gen2(a, b, s, hard_f64_mul, soft_f64_mul, - f64_is_zon2, NULL, f64_mul_fast_test, f64_mul_fast_op); + f64_is_zon2, f64_addsubmul_post); } /* @@ -1834,14 +1797,14 @@ float32 QEMU_FLATTEN float32_div(float32 a, float32 b, float_status *s) { return float32_gen2(a, b, s, hard_f32_div, soft_f32_div, - f32_div_pre, f32_div_post, NULL, NULL); + f32_div_pre, f32_div_post); } float64 QEMU_FLATTEN float64_div(float64 a, float64 b, float_status *s) { return float64_gen2(a, b, s, hard_f64_div, soft_f64_div, - f64_div_pre, f64_div_post, NULL, NULL); + f64_div_pre, f64_div_post); } /*