From: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
To: qemu-ppc@nongnu.org, david@gibson.dropbear.id.au, rth@twiddle.net
Cc: qemu-devel@nongnu.org, bharata@linux.vnet.ibm.com,
nikunj@linux.vnet.ibm.com
Subject: [Qemu-devel] [PATCH v1] target/ppc: rewrite f[n]m[add, sub] using float64_muladd
Date: Wed, 1 Mar 2017 20:54:14 +0530 [thread overview]
Message-ID: <1488381854-7275-1-git-send-email-nikunj@linux.vnet.ibm.com> (raw)
Use the softfloat api for fused multiply-add. Also, generate VXISI using
a helper function by computing intermediate result.
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
---
v0:
* Use MADD/MSUB_FLAGS as used by VSX instructions
* Introduce helper float64_madd_set_vxisi()
---
target/ppc/fpu_helper.c | 218 +++++++++++-------------------------------------
1 file changed, 49 insertions(+), 169 deletions(-)
diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
index 58aee64..ed7e84a 100644
--- a/target/ppc/fpu_helper.c
+++ b/target/ppc/fpu_helper.c
@@ -743,178 +743,63 @@ uint64_t helper_frim(CPUPPCState *env, uint64_t arg)
return do_fri(env, arg, float_round_down);
}
-/* fmadd - fmadd. */
-uint64_t helper_fmadd(CPUPPCState *env, uint64_t arg1, uint64_t arg2,
- uint64_t arg3)
-{
- CPU_DoubleU farg1, farg2, farg3;
-
- farg1.ll = arg1;
- farg2.ll = arg2;
- farg3.ll = arg3;
-
- if (unlikely((float64_is_infinity(farg1.d) && float64_is_zero(farg2.d)) ||
- (float64_is_zero(farg1.d) && float64_is_infinity(farg2.d)))) {
- /* Multiplication of zero by infinity */
- farg1.ll = float_invalid_op_excp(env, POWERPC_EXCP_FP_VXIMZ, 1);
- } else {
- if (unlikely(float64_is_signaling_nan(farg1.d, &env->fp_status) ||
- float64_is_signaling_nan(farg2.d, &env->fp_status) ||
- float64_is_signaling_nan(farg3.d, &env->fp_status))) {
- /* sNaN operation */
- float_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN, 1);
- }
- /* This is the way the PowerPC specification defines it */
- float128 ft0_128, ft1_128;
-
- ft0_128 = float64_to_float128(farg1.d, &env->fp_status);
- ft1_128 = float64_to_float128(farg2.d, &env->fp_status);
- ft0_128 = float128_mul(ft0_128, ft1_128, &env->fp_status);
- if (unlikely(float128_is_infinity(ft0_128) &&
- float64_is_infinity(farg3.d) &&
- float128_is_neg(ft0_128) != float64_is_neg(farg3.d))) {
- /* Magnitude subtraction of infinities */
- farg1.ll = float_invalid_op_excp(env, POWERPC_EXCP_FP_VXISI, 1);
- } else {
- ft1_128 = float64_to_float128(farg3.d, &env->fp_status);
- ft0_128 = float128_add(ft0_128, ft1_128, &env->fp_status);
- farg1.d = float128_to_float64(ft0_128, &env->fp_status);
- }
- }
-
- return farg1.ll;
-}
-
-/* fmsub - fmsub. */
-uint64_t helper_fmsub(CPUPPCState *env, uint64_t arg1, uint64_t arg2,
- uint64_t arg3)
-{
- CPU_DoubleU farg1, farg2, farg3;
-
- farg1.ll = arg1;
- farg2.ll = arg2;
- farg3.ll = arg3;
-
- if (unlikely((float64_is_infinity(farg1.d) && float64_is_zero(farg2.d)) ||
- (float64_is_zero(farg1.d) &&
- float64_is_infinity(farg2.d)))) {
- /* Multiplication of zero by infinity */
- farg1.ll = float_invalid_op_excp(env, POWERPC_EXCP_FP_VXIMZ, 1);
- } else {
- if (unlikely(float64_is_signaling_nan(farg1.d, &env->fp_status) ||
- float64_is_signaling_nan(farg2.d, &env->fp_status) ||
- float64_is_signaling_nan(farg3.d, &env->fp_status))) {
- /* sNaN operation */
- float_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN, 1);
- }
- /* This is the way the PowerPC specification defines it */
- float128 ft0_128, ft1_128;
-
- ft0_128 = float64_to_float128(farg1.d, &env->fp_status);
- ft1_128 = float64_to_float128(farg2.d, &env->fp_status);
- ft0_128 = float128_mul(ft0_128, ft1_128, &env->fp_status);
- if (unlikely(float128_is_infinity(ft0_128) &&
- float64_is_infinity(farg3.d) &&
- float128_is_neg(ft0_128) == float64_is_neg(farg3.d))) {
- /* Magnitude subtraction of infinities */
- farg1.ll = float_invalid_op_excp(env, POWERPC_EXCP_FP_VXISI, 1);
- } else {
- ft1_128 = float64_to_float128(farg3.d, &env->fp_status);
- ft0_128 = float128_sub(ft0_128, ft1_128, &env->fp_status);
- farg1.d = float128_to_float64(ft0_128, &env->fp_status);
- }
- }
- return farg1.ll;
-}
+#define MADD_FLGS 0
+#define MSUB_FLGS float_muladd_negate_c
+#define NMADD_FLGS float_muladd_negate_result
+#define NMSUB_FLGS (float_muladd_negate_c | float_muladd_negate_result)
-/* fnmadd - fnmadd. */
-uint64_t helper_fnmadd(CPUPPCState *env, uint64_t arg1, uint64_t arg2,
- uint64_t arg3)
+static void float64_madd_set_vxisi(CPUPPCState *env, float64 a, float64 b,
+ float64 c, unsigned int flags)
{
- CPU_DoubleU farg1, farg2, farg3;
-
- farg1.ll = arg1;
- farg2.ll = arg2;
- farg3.ll = arg3;
+ float64 f = float64_mul(a, b, &env->fp_status);
- if (unlikely((float64_is_infinity(farg1.d) && float64_is_zero(farg2.d)) ||
- (float64_is_zero(farg1.d) && float64_is_infinity(farg2.d)))) {
- /* Multiplication of zero by infinity */
- farg1.ll = float_invalid_op_excp(env, POWERPC_EXCP_FP_VXIMZ, 1);
- } else {
- if (unlikely(float64_is_signaling_nan(farg1.d, &env->fp_status) ||
- float64_is_signaling_nan(farg2.d, &env->fp_status) ||
- float64_is_signaling_nan(farg3.d, &env->fp_status))) {
- /* sNaN operation */
- float_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN, 1);
- }
- /* This is the way the PowerPC specification defines it */
- float128 ft0_128, ft1_128;
-
- ft0_128 = float64_to_float128(farg1.d, &env->fp_status);
- ft1_128 = float64_to_float128(farg2.d, &env->fp_status);
- ft0_128 = float128_mul(ft0_128, ft1_128, &env->fp_status);
- if (unlikely(float128_is_infinity(ft0_128) &&
- float64_is_infinity(farg3.d) &&
- float128_is_neg(ft0_128) != float64_is_neg(farg3.d))) {
- /* Magnitude subtraction of infinities */
- farg1.ll = float_invalid_op_excp(env, POWERPC_EXCP_FP_VXISI, 1);
- } else {
- ft1_128 = float64_to_float128(farg3.d, &env->fp_status);
- ft0_128 = float128_add(ft0_128, ft1_128, &env->fp_status);
- farg1.d = float128_to_float64(ft0_128, &env->fp_status);
- }
- if (likely(!float64_is_any_nan(farg1.d))) {
- farg1.d = float64_chs(farg1.d);
+ /* a*b = ∞ and c = ∞, find ∞ - ∞ case and set VXISI */
+ if (float64_is_infinity(f) && float64_is_infinity(c)) {
+ if ((f ^ c) == 0) {
+ /* Both negative/positive inifinity and substraction*/
+ if (flags & MSUB_FLGS) {
+ /* 1. ∞ - ∞
+ * 2. (-∞) - (-∞)
+ */
+ float_invalid_op_excp(env, POWERPC_EXCP_FP_VXISI, 1);
+ }
+ } else if (!(flags & MSUB_FLGS)) {
+ /* Opposite sign and addition
+ * 1) ∞ + (-∞)
+ * 2) (-∞) + ∞
+ */
+ float_invalid_op_excp(env, POWERPC_EXCP_FP_VXISI, 1);
}
}
- return farg1.ll;
}
-/* fnmsub - fnmsub. */
-uint64_t helper_fnmsub(CPUPPCState *env, uint64_t arg1, uint64_t arg2,
- uint64_t arg3)
-{
- CPU_DoubleU farg1, farg2, farg3;
-
- farg1.ll = arg1;
- farg2.ll = arg2;
- farg3.ll = arg3;
-
- if (unlikely((float64_is_infinity(farg1.d) && float64_is_zero(farg2.d)) ||
- (float64_is_zero(farg1.d) &&
- float64_is_infinity(farg2.d)))) {
- /* Multiplication of zero by infinity */
- farg1.ll = float_invalid_op_excp(env, POWERPC_EXCP_FP_VXIMZ, 1);
- } else {
- if (unlikely(float64_is_signaling_nan(farg1.d, &env->fp_status) ||
- float64_is_signaling_nan(farg2.d, &env->fp_status) ||
- float64_is_signaling_nan(farg3.d, &env->fp_status))) {
- /* sNaN operation */
- float_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN, 1);
- }
- /* This is the way the PowerPC specification defines it */
- float128 ft0_128, ft1_128;
-
- ft0_128 = float64_to_float128(farg1.d, &env->fp_status);
- ft1_128 = float64_to_float128(farg2.d, &env->fp_status);
- ft0_128 = float128_mul(ft0_128, ft1_128, &env->fp_status);
- if (unlikely(float128_is_infinity(ft0_128) &&
- float64_is_infinity(farg3.d) &&
- float128_is_neg(ft0_128) == float64_is_neg(farg3.d))) {
- /* Magnitude subtraction of infinities */
- farg1.ll = float_invalid_op_excp(env, POWERPC_EXCP_FP_VXISI, 1);
- } else {
- ft1_128 = float64_to_float128(farg3.d, &env->fp_status);
- ft0_128 = float128_sub(ft0_128, ft1_128, &env->fp_status);
- farg1.d = float128_to_float64(ft0_128, &env->fp_status);
- }
- if (likely(!float64_is_any_nan(farg1.d))) {
- farg1.d = float64_chs(farg1.d);
- }
- }
- return farg1.ll;
+#define FPU_FMADD(op, madd_flags) \
+uint64_t helper_##op(CPUPPCState *env, uint64_t arg1, \
+ uint64_t arg2, uint64_t arg3) \
+{ \
+ if (unlikely((float64_is_infinity(arg1) && float64_is_zero(arg2)) || \
+ (float64_is_zero(arg1) && float64_is_infinity(arg2)))) { \
+ /* Multiplication of zero by infinity */ \
+ arg1 = float_invalid_op_excp(env, POWERPC_EXCP_FP_VXIMZ, 1); \
+ } else { \
+ if (unlikely(float64_is_signaling_nan(arg1, &env->fp_status) || \
+ float64_is_signaling_nan(arg2, &env->fp_status) || \
+ float64_is_signaling_nan(arg3, &env->fp_status))) { \
+ /* sNaN operation */ \
+ float_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN, 1); \
+ } \
+ \
+ float64_madd_set_vxisi(env, arg1, arg2, arg3, madd_flags); \
+ arg1 = float64_muladd(arg1, arg2, arg3, madd_flags, \
+ &env->fp_status); \
+ float_check_status(env); \
+ } \
+ return arg1; \
}
+FPU_FMADD(fmadd, MADD_FLGS)
+FPU_FMADD(fnmadd, NMADD_FLGS)
+FPU_FMADD(fmsub, MSUB_FLGS)
+FPU_FMADD(fnmsub, NMSUB_FLGS)
/* frsp - frsp. */
uint64_t helper_frsp(CPUPPCState *env, uint64_t arg)
@@ -2384,11 +2269,6 @@ void helper_##op(CPUPPCState *env, uint32_t opcode) \
float_check_status(env); \
}
-#define MADD_FLGS 0
-#define MSUB_FLGS float_muladd_negate_c
-#define NMADD_FLGS float_muladd_negate_result
-#define NMSUB_FLGS (float_muladd_negate_c | float_muladd_negate_result)
-
VSX_MADD(xsmaddadp, 1, float64, VsrD(0), MADD_FLGS, 1, 1, 0)
VSX_MADD(xsmaddmdp, 1, float64, VsrD(0), MADD_FLGS, 0, 1, 0)
VSX_MADD(xsmsubadp, 1, float64, VsrD(0), MSUB_FLGS, 1, 1, 0)
--
2.7.4
next reply other threads:[~2017-03-01 15:25 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-01 15:24 Nikunj A Dadhania [this message]
2017-03-02 0:29 ` [Qemu-devel] [PATCH v1] target/ppc: rewrite f[n]m[add, sub] using float64_muladd David Gibson
2017-03-02 2:22 ` Richard Henderson
2017-03-02 4:08 ` [Qemu-devel] [Qemu-ppc] " Nikunj Dadhania
2017-03-02 5:03 ` Nikunj A Dadhania
2017-03-02 2:36 ` [Qemu-devel] " Richard Henderson
2017-03-02 4:14 ` [Qemu-devel] [Qemu-ppc] " Nikunj Dadhania
2017-03-02 5:04 ` Nikunj A Dadhania
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