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[189.204.200.163]) by smtp.gmail.com with ESMTPSA id s5sm8500553qkg.88.2021.05.16.05.35.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 16 May 2021 05:35:00 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Subject: [PULL 34/46] softfloat: Move addsub_floats to softfloat-parts.c.inc Date: Sun, 16 May 2021 07:34:19 -0500 Message-Id: <20210516123431.718318-35-richard.henderson@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210516123431.718318-1-richard.henderson@linaro.org> References: <20210516123431.718318-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::f2f; envelope-from=richard.henderson@linaro.org; helo=mail-qv1-xf2f.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, =?utf-8?q?Alex_Benn=C3=A9e?= Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: "Qemu-devel" In preparation for implementing multiple sizes. Rename to parts_addsub, split out parts_add/sub_normal for future reuse with muladd. Reviewed-by: Alex Bennée Signed-off-by: Richard Henderson --- fpu/softfloat.c | 253 ++++++++++++++----------------- fpu/softfloat-parts-addsub.c.inc | 62 ++++++++ fpu/softfloat-parts.c.inc | 81 ++++++++++ 3 files changed, 255 insertions(+), 141 deletions(-) create mode 100644 fpu/softfloat-parts-addsub.c.inc -- 2.25.1 diff --git a/fpu/softfloat.c b/fpu/softfloat.c index 817a91de85..afeef00097 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -749,6 +749,26 @@ static void parts128_uncanon(FloatParts128 *p, float_status *status, #define parts_uncanon(A, S, F) \ PARTS_GENERIC_64_128(uncanon, A)(A, S, F) +static void parts64_add_normal(FloatParts64 *a, FloatParts64 *b); +static void parts128_add_normal(FloatParts128 *a, FloatParts128 *b); + +#define parts_add_normal(A, B) \ + PARTS_GENERIC_64_128(add_normal, A)(A, B) + +static bool parts64_sub_normal(FloatParts64 *a, FloatParts64 *b); +static bool parts128_sub_normal(FloatParts128 *a, FloatParts128 *b); + +#define parts_sub_normal(A, B) \ + PARTS_GENERIC_64_128(sub_normal, A)(A, B) + +static FloatParts64 *parts64_addsub(FloatParts64 *a, FloatParts64 *b, + float_status *s, bool subtract); +static FloatParts128 *parts128_addsub(FloatParts128 *a, FloatParts128 *b, + float_status *s, bool subtract); + +#define parts_addsub(A, B, S, Z) \ + PARTS_GENERIC_64_128(addsub, A)(A, B, S, Z) + /* * Helper functions for softfloat-parts.c.inc, per-size operations. */ @@ -756,6 +776,21 @@ static void parts128_uncanon(FloatParts128 *p, float_status *status, #define FRAC_GENERIC_64_128(NAME, P) \ QEMU_GENERIC(P, (FloatParts128 *, frac128_##NAME), frac64_##NAME) +static bool frac64_add(FloatParts64 *r, FloatParts64 *a, FloatParts64 *b) +{ + return uadd64_overflow(a->frac, b->frac, &r->frac); +} + +static bool frac128_add(FloatParts128 *r, FloatParts128 *a, FloatParts128 *b) +{ + bool c = 0; + r->frac_lo = uadd64_carry(a->frac_lo, b->frac_lo, &c); + r->frac_hi = uadd64_carry(a->frac_hi, b->frac_hi, &c); + return c; +} + +#define frac_add(R, A, B) FRAC_GENERIC_64_128(add, R)(R, A, B) + static bool frac64_addi(FloatParts64 *r, FloatParts64 *a, uint64_t c) { return uadd64_overflow(a->frac, c, &r->frac); @@ -824,6 +859,20 @@ static bool frac128_eqz(FloatParts128 *a) #define frac_eqz(A) FRAC_GENERIC_64_128(eqz, A)(A) +static void frac64_neg(FloatParts64 *a) +{ + a->frac = -a->frac; +} + +static void frac128_neg(FloatParts128 *a) +{ + bool c = 0; + a->frac_lo = usub64_borrow(0, a->frac_lo, &c); + a->frac_hi = usub64_borrow(0, a->frac_hi, &c); +} + +#define frac_neg(A) FRAC_GENERIC_64_128(neg, A)(A) + static int frac64_normalize(FloatParts64 *a) { if (a->frac) { @@ -891,18 +940,36 @@ static void frac128_shrjam(FloatParts128 *a, int c) #define frac_shrjam(A, C) FRAC_GENERIC_64_128(shrjam, A)(A, C) -#define partsN(NAME) parts64_##NAME -#define FloatPartsN FloatParts64 +static bool frac64_sub(FloatParts64 *r, FloatParts64 *a, FloatParts64 *b) +{ + return usub64_overflow(a->frac, b->frac, &r->frac); +} +static bool frac128_sub(FloatParts128 *r, FloatParts128 *a, FloatParts128 *b) +{ + bool c = 0; + r->frac_lo = usub64_borrow(a->frac_lo, b->frac_lo, &c); + r->frac_hi = usub64_borrow(a->frac_hi, b->frac_hi, &c); + return c; +} + +#define frac_sub(R, A, B) FRAC_GENERIC_64_128(sub, R)(R, A, B) + +#define partsN(NAME) glue(glue(glue(parts,N),_),NAME) +#define FloatPartsN glue(FloatParts,N) + +#define N 64 + +#include "softfloat-parts-addsub.c.inc" #include "softfloat-parts.c.inc" -#undef partsN -#undef FloatPartsN -#define partsN(NAME) parts128_##NAME -#define FloatPartsN FloatParts128 +#undef N +#define N 128 +#include "softfloat-parts-addsub.c.inc" #include "softfloat-parts.c.inc" +#undef N #undef partsN #undef FloatPartsN @@ -980,165 +1047,73 @@ static float64 float64_round_pack_canonical(FloatParts64 *p, } /* - * Returns the result of adding or subtracting the values of the - * floating-point values `a' and `b'. The operation is performed - * according to the IEC/IEEE Standard for Binary Floating-Point - * Arithmetic. + * Addition and subtraction */ -static FloatParts64 addsub_floats(FloatParts64 a, FloatParts64 b, bool subtract, - float_status *s) +static float16 QEMU_FLATTEN +float16_addsub(float16 a, float16 b, float_status *status, bool subtract) { - bool a_sign = a.sign; - bool b_sign = b.sign ^ subtract; - - if (a_sign != b_sign) { - /* Subtraction */ - - if (a.cls == float_class_normal && b.cls == float_class_normal) { - if (a.exp > b.exp || (a.exp == b.exp && a.frac >= b.frac)) { - shift64RightJamming(b.frac, a.exp - b.exp, &b.frac); - a.frac = a.frac - b.frac; - } else { - shift64RightJamming(a.frac, b.exp - a.exp, &a.frac); - a.frac = b.frac - a.frac; - a.exp = b.exp; - a_sign ^= 1; - } - - if (a.frac == 0) { - a.cls = float_class_zero; - a.sign = s->float_rounding_mode == float_round_down; - } else { - int shift = clz64(a.frac); - a.frac = a.frac << shift; - a.exp = a.exp - shift; - a.sign = a_sign; - } - return a; - } - if (is_nan(a.cls) || is_nan(b.cls)) { - return *parts_pick_nan(&a, &b, s); - } - if (a.cls == float_class_inf) { - if (b.cls == float_class_inf) { - float_raise(float_flag_invalid, s); - parts_default_nan(&a, s); - } - return a; - } - if (a.cls == float_class_zero && b.cls == float_class_zero) { - a.sign = s->float_rounding_mode == float_round_down; - return a; - } - if (a.cls == float_class_zero || b.cls == float_class_inf) { - b.sign = a_sign ^ 1; - return b; - } - if (b.cls == float_class_zero) { - return a; - } - } else { - /* Addition */ - if (a.cls == float_class_normal && b.cls == float_class_normal) { - if (a.exp > b.exp) { - shift64RightJamming(b.frac, a.exp - b.exp, &b.frac); - } else if (a.exp < b.exp) { - shift64RightJamming(a.frac, b.exp - a.exp, &a.frac); - a.exp = b.exp; - } - - if (uadd64_overflow(a.frac, b.frac, &a.frac)) { - shift64RightJamming(a.frac, 1, &a.frac); - a.frac |= DECOMPOSED_IMPLICIT_BIT; - a.exp += 1; - } - return a; - } - if (is_nan(a.cls) || is_nan(b.cls)) { - return *parts_pick_nan(&a, &b, s); - } - if (a.cls == float_class_inf || b.cls == float_class_zero) { - return a; - } - if (b.cls == float_class_inf || a.cls == float_class_zero) { - b.sign = b_sign; - return b; - } - } - g_assert_not_reached(); -} - -/* - * Returns the result of adding or subtracting the floating-point - * values `a' and `b'. The operation is performed according to the - * IEC/IEEE Standard for Binary Floating-Point Arithmetic. - */ - -float16 QEMU_FLATTEN float16_add(float16 a, float16 b, float_status *status) -{ - FloatParts64 pa, pb, pr; + FloatParts64 pa, pb, *pr; float16_unpack_canonical(&pa, a, status); float16_unpack_canonical(&pb, b, status); - pr = addsub_floats(pa, pb, false, status); + pr = parts_addsub(&pa, &pb, status, subtract); - return float16_round_pack_canonical(&pr, status); + return float16_round_pack_canonical(pr, status); } -float16 QEMU_FLATTEN float16_sub(float16 a, float16 b, float_status *status) +float16 float16_add(float16 a, float16 b, float_status *status) { - FloatParts64 pa, pb, pr; + return float16_addsub(a, b, status, false); +} - float16_unpack_canonical(&pa, a, status); - float16_unpack_canonical(&pb, b, status); - pr = addsub_floats(pa, pb, true, status); - - return float16_round_pack_canonical(&pr, status); +float16 float16_sub(float16 a, float16 b, float_status *status) +{ + return float16_addsub(a, b, status, true); } static float32 QEMU_SOFTFLOAT_ATTR -soft_f32_addsub(float32 a, float32 b, bool subtract, float_status *status) +soft_f32_addsub(float32 a, float32 b, float_status *status, bool subtract) { - FloatParts64 pa, pb, pr; + FloatParts64 pa, pb, *pr; float32_unpack_canonical(&pa, a, status); float32_unpack_canonical(&pb, b, status); - pr = addsub_floats(pa, pb, subtract, status); + pr = parts_addsub(&pa, &pb, status, subtract); - return float32_round_pack_canonical(&pr, status); + return float32_round_pack_canonical(pr, status); } -static inline float32 soft_f32_add(float32 a, float32 b, float_status *status) +static float32 soft_f32_add(float32 a, float32 b, float_status *status) { - return soft_f32_addsub(a, b, false, status); + return soft_f32_addsub(a, b, status, false); } -static inline float32 soft_f32_sub(float32 a, float32 b, float_status *status) +static float32 soft_f32_sub(float32 a, float32 b, float_status *status) { - return soft_f32_addsub(a, b, true, status); + return soft_f32_addsub(a, b, status, true); } static float64 QEMU_SOFTFLOAT_ATTR -soft_f64_addsub(float64 a, float64 b, bool subtract, float_status *status) +soft_f64_addsub(float64 a, float64 b, float_status *status, bool subtract) { - FloatParts64 pa, pb, pr; + FloatParts64 pa, pb, *pr; float64_unpack_canonical(&pa, a, status); float64_unpack_canonical(&pb, b, status); - pr = addsub_floats(pa, pb, subtract, status); + pr = parts_addsub(&pa, &pb, status, subtract); - return float64_round_pack_canonical(&pr, status); + return float64_round_pack_canonical(pr, status); } -static inline float64 soft_f64_add(float64 a, float64 b, float_status *status) +static float64 soft_f64_add(float64 a, float64 b, float_status *status) { - return soft_f64_addsub(a, b, false, status); + return soft_f64_addsub(a, b, status, false); } -static inline float64 soft_f64_sub(float64 a, float64 b, float_status *status) +static float64 soft_f64_sub(float64 a, float64 b, float_status *status) { - return soft_f64_addsub(a, b, true, status); + return soft_f64_addsub(a, b, status, true); } static float hard_f32_add(float a, float b) @@ -1216,30 +1191,26 @@ float64_sub(float64 a, float64 b, float_status *s) return float64_addsub(a, b, s, hard_f64_sub, soft_f64_sub); } -/* - * Returns the result of adding or subtracting the bfloat16 - * values `a' and `b'. - */ -bfloat16 QEMU_FLATTEN bfloat16_add(bfloat16 a, bfloat16 b, float_status *status) +static bfloat16 QEMU_FLATTEN +bfloat16_addsub(bfloat16 a, bfloat16 b, float_status *status, bool subtract) { - FloatParts64 pa, pb, pr; + FloatParts64 pa, pb, *pr; bfloat16_unpack_canonical(&pa, a, status); bfloat16_unpack_canonical(&pb, b, status); - pr = addsub_floats(pa, pb, false, status); + pr = parts_addsub(&pa, &pb, status, subtract); - return bfloat16_round_pack_canonical(&pr, status); + return bfloat16_round_pack_canonical(pr, status); } -bfloat16 QEMU_FLATTEN bfloat16_sub(bfloat16 a, bfloat16 b, float_status *status) +bfloat16 bfloat16_add(bfloat16 a, bfloat16 b, float_status *status) { - FloatParts64 pa, pb, pr; + return bfloat16_addsub(a, b, status, false); +} - bfloat16_unpack_canonical(&pa, a, status); - bfloat16_unpack_canonical(&pb, b, status); - pr = addsub_floats(pa, pb, true, status); - - return bfloat16_round_pack_canonical(&pr, status); +bfloat16 bfloat16_sub(bfloat16 a, bfloat16 b, float_status *status) +{ + return bfloat16_addsub(a, b, status, true); } /* diff --git a/fpu/softfloat-parts-addsub.c.inc b/fpu/softfloat-parts-addsub.c.inc new file mode 100644 index 0000000000..ae5c1017c5 --- /dev/null +++ b/fpu/softfloat-parts-addsub.c.inc @@ -0,0 +1,62 @@ +/* + * Floating point arithmetic implementation + * + * The code in this source file is derived from release 2a of the SoftFloat + * IEC/IEEE Floating-point Arithmetic Package. Those parts of the code (and + * some later contributions) are provided under that license, as detailed below. + * It has subsequently been modified by contributors to the QEMU Project, + * so some portions are provided under: + * the SoftFloat-2a license + * the BSD license + * GPL-v2-or-later + * + * Any future contributions to this file after December 1st 2014 will be + * taken to be licensed under the Softfloat-2a license unless specifically + * indicated otherwise. + */ + +static void partsN(add_normal)(FloatPartsN *a, FloatPartsN *b) +{ + int exp_diff = a->exp - b->exp; + + if (exp_diff > 0) { + frac_shrjam(b, exp_diff); + } else if (exp_diff < 0) { + frac_shrjam(a, -exp_diff); + a->exp = b->exp; + } + + if (frac_add(a, a, b)) { + frac_shrjam(a, 1); + a->frac_hi |= DECOMPOSED_IMPLICIT_BIT; + a->exp += 1; + } +} + +static bool partsN(sub_normal)(FloatPartsN *a, FloatPartsN *b) +{ + int exp_diff = a->exp - b->exp; + int shift; + + if (exp_diff > 0) { + frac_shrjam(b, exp_diff); + frac_sub(a, a, b); + } else if (exp_diff < 0) { + a->exp = b->exp; + a->sign ^= 1; + frac_shrjam(a, -exp_diff); + frac_sub(a, b, a); + } else if (frac_sub(a, a, b)) { + /* Overflow means that A was less than B. */ + frac_neg(a); + a->sign ^= 1; + } + + shift = frac_normalize(a); + if (likely(shift < N)) { + a->exp -= shift; + return true; + } + a->cls = float_class_zero; + return false; +} diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc index efdc724770..cfce9f6421 100644 --- a/fpu/softfloat-parts.c.inc +++ b/fpu/softfloat-parts.c.inc @@ -281,3 +281,84 @@ static void partsN(uncanon)(FloatPartsN *p, float_status *s, p->exp = exp; float_raise(flags, s); } + +/* + * Returns the result of adding or subtracting the values of the + * floating-point values `a' and `b'. The operation is performed + * according to the IEC/IEEE Standard for Binary Floating-Point + * Arithmetic. + */ +static FloatPartsN *partsN(addsub)(FloatPartsN *a, FloatPartsN *b, + float_status *s, bool subtract) +{ + bool b_sign = b->sign ^ subtract; + int ab_mask = float_cmask(a->cls) | float_cmask(b->cls); + + if (a->sign != b_sign) { + /* Subtraction */ + if (likely(ab_mask == float_cmask_normal)) { + if (parts_sub_normal(a, b)) { + return a; + } + /* Subtract was exact, fall through to set sign. */ + ab_mask = float_cmask_zero; + } + + if (ab_mask == float_cmask_zero) { + a->sign = s->float_rounding_mode == float_round_down; + return a; + } + + if (unlikely(ab_mask & float_cmask_anynan)) { + goto p_nan; + } + + if (ab_mask & float_cmask_inf) { + if (a->cls != float_class_inf) { + /* N - Inf */ + goto return_b; + } + if (b->cls != float_class_inf) { + /* Inf - N */ + return a; + } + /* Inf - Inf */ + float_raise(float_flag_invalid, s); + parts_default_nan(a, s); + return a; + } + } else { + /* Addition */ + if (likely(ab_mask == float_cmask_normal)) { + parts_add_normal(a, b); + return a; + } + + if (ab_mask == float_cmask_zero) { + return a; + } + + if (unlikely(ab_mask & float_cmask_anynan)) { + goto p_nan; + } + + if (ab_mask & float_cmask_inf) { + a->cls = float_class_inf; + return a; + } + } + + if (b->cls == float_class_zero) { + g_assert(a->cls == float_class_normal); + return a; + } + + g_assert(a->cls == float_class_zero); + g_assert(b->cls == float_class_normal); + return_b: + b->sign = b_sign; + return b; + + p_nan: + return parts_pick_nan(a, b, s); +}