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[Qemu-ppc] [2.3 V2 PATCH 1/6] target-ppc: VXSQRT Should Not Be Set for N
From: |
Tom Musta |
Subject: |
[Qemu-ppc] [2.3 V2 PATCH 1/6] target-ppc: VXSQRT Should Not Be Set for NaNs |
Date: |
Wed, 12 Nov 2014 15:45:59 -0600 |
The Power ISA square root instructions (fsqrt[s], frsqrte[s]) must
set the FPSCR[VXSQRT] flag when operating on a negative value.
However, NaNs have no sign and therefore this flag should not
be set when operating on one.
Change the order of the checks in the helper code. Move the
SNaN-to-QNaN macro to the top of the file so that it can be
re-used.
Signed-off-by: Tom Musta <address@hidden>
---
target-ppc/fpu_helper.c | 29 +++++++++++++++++------------
1 files changed, 17 insertions(+), 12 deletions(-)
diff --git a/target-ppc/fpu_helper.c b/target-ppc/fpu_helper.c
index 7f74466..81db60f 100644
--- a/target-ppc/fpu_helper.c
+++ b/target-ppc/fpu_helper.c
@@ -19,6 +19,9 @@
#include "cpu.h"
#include "exec/helper-proto.h"
+#define float64_snan_to_qnan(x) ((x) | 0x0008000000000000ULL)
+#define float32_snan_to_qnan(x) ((x) | 0x00400000)
+
/*****************************************************************************/
/* Floating point operations helpers */
uint64_t helper_float32_to_float64(CPUPPCState *env, uint32_t arg)
@@ -920,14 +923,16 @@ uint64_t helper_fsqrt(CPUPPCState *env, uint64_t arg)
farg.ll = arg;
- if (unlikely(float64_is_neg(farg.d) && !float64_is_zero(farg.d))) {
- /* Square root of a negative nonzero number */
- farg.ll = fload_invalid_op_excp(env, POWERPC_EXCP_FP_VXSQRT, 1);
- } else {
+ if (unlikely(float64_is_any_nan(farg.d))) {
if (unlikely(float64_is_signaling_nan(farg.d))) {
- /* sNaN square root */
+ /* sNaN reciprocal square root */
fload_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN, 1);
+ farg.ll = float64_snan_to_qnan(farg.ll);
}
+ } else if (unlikely(float64_is_neg(farg.d) && !float64_is_zero(farg.d))) {
+ /* Square root of a negative nonzero number */
+ farg.ll = fload_invalid_op_excp(env, POWERPC_EXCP_FP_VXSQRT, 1);
+ } else {
farg.d = float64_sqrt(farg.d, &env->fp_status);
}
return farg.ll;
@@ -974,17 +979,20 @@ uint64_t helper_frsqrte(CPUPPCState *env, uint64_t arg)
farg.ll = arg;
- if (unlikely(float64_is_neg(farg.d) && !float64_is_zero(farg.d))) {
- /* Reciprocal square root of a negative nonzero number */
- farg.ll = fload_invalid_op_excp(env, POWERPC_EXCP_FP_VXSQRT, 1);
- } else {
+ if (unlikely(float64_is_any_nan(farg.d))) {
if (unlikely(float64_is_signaling_nan(farg.d))) {
/* sNaN reciprocal square root */
fload_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN, 1);
+ farg.ll = float64_snan_to_qnan(farg.ll);
}
+ } else if (unlikely(float64_is_neg(farg.d) && !float64_is_zero(farg.d))) {
+ /* Reciprocal square root of a negative nonzero number */
+ farg.ll = fload_invalid_op_excp(env, POWERPC_EXCP_FP_VXSQRT, 1);
+ } else {
farg.d = float64_sqrt(farg.d, &env->fp_status);
farg.d = float64_div(float64_one, farg.d, &env->fp_status);
}
+
return farg.ll;
}
@@ -2382,9 +2390,6 @@ void helper_##op(CPUPPCState *env, uint32_t opcode)
\
VSX_SCALAR_CMP(xscmpodp, 1)
VSX_SCALAR_CMP(xscmpudp, 0)
-#define float64_snan_to_qnan(x) ((x) | 0x0008000000000000ULL)
-#define float32_snan_to_qnan(x) ((x) | 0x00400000)
-
/* VSX_MAX_MIN - VSX floating point maximum/minimum
* name - instruction mnemonic
* op - operation (max or min)
--
1.7.1
- [Qemu-ppc] [2.3 V2 PATCH 0/6] target-ppc: Assorted Floating Point Bugs and Cleanup, Tom Musta, 2014/11/12
- [Qemu-ppc] [2.3 V2 PATCH 3/6] target-ppc: mffs. Should Set CR1 from FPSCR Bits, Tom Musta, 2014/11/12
- [Qemu-ppc] [2.3 V2 PATCH 4/6] target-ppc: Fully Migrate to gen_set_cr1_from_fpscr, Tom Musta, 2014/11/12
- [Qemu-ppc] [2.3 V2 PATCH 6/6] target-ppc: Eliminate set_fprf Argument From helper_compute_fprf, Tom Musta, 2014/11/12
- [Qemu-ppc] [2.3 V2 PATCH 5/6] target-ppc: Eliminate set_fprf Argument From gen_compute_fprf, Tom Musta, 2014/11/12
- Re: [Qemu-ppc] [2.3 V2 PATCH 0/6] target-ppc: Assorted Floating Point Bugs and Cleanup, Alexander Graf, 2014/11/20