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[Qemu-ppc] [PATCH v5 5/9] target-mips: Activate IEEE 274-2008 signaling
From: |
Aleksandar Markovic |
Subject: |
[Qemu-ppc] [PATCH v5 5/9] target-mips: Activate IEEE 274-2008 signaling NaN bit meaning |
Date: |
Mon, 18 Apr 2016 18:03:38 +0200 |
From: Aleksandar Markovic <address@hidden>
Functions mips_cpu_reset() and msa_reset() are updated so that flag
snan_bit_is_one is properly set for any Mips FPU/MSA configuration.
For main FPUs, CPUs with FCR31's FCR31_NAN2008 bit set will invoke
set_snan_bit_is_one(0). For MSA, as it is IEEE 274-2008 compliant
from it inception, set_snan_bit_is_one(0) will always be invoked.
By applying this patch, a number of incorrect behaviors for CPU
configurations that require IEEE 274-2008 compliance will be fixed.
Those are behaviors that (up to the moment of applying this patch)
did not get the desired functionality from SoftFloat library with
respect to distinguishing between quiet and signaling NaN, getting
default NaN values (both quiet and signaling), establishing if a
floating point number is Nan or not, etc.
Just two examples:
* <MAX|MAXA>.<D|S> will now correctly detect and propagate NaNs.
* CLASS.<D|S> will now correcty detect NaN flavors, both their
CPU FPU and MSA version.
Signed-off-by: Thomas Schwinge <address@hidden>
Signed-off-by: Maciej W. Rozycki <address@hidden>
Signed-off-by: Aleksandar Markovic <address@hidden>
---
target-mips/translate.c | 6 +++++-
target-mips/translate_init.c | 3 ++-
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/target-mips/translate.c b/target-mips/translate.c
index e934884..2cdd2bd 100644
--- a/target-mips/translate.c
+++ b/target-mips/translate.c
@@ -20129,7 +20129,11 @@ void cpu_state_reset(CPUMIPSState *env)
env->CP0_PageGrain = env->cpu_model->CP0_PageGrain;
env->active_fpu.fcr0 = env->cpu_model->CP1_fcr0;
env->active_fpu.fcr31 = env->cpu_model->CP1_fcr31;
- set_snan_bit_is_one(1, &env->active_fpu.fp_status);
+ if ((env->active_fpu.fcr31 >> FCR31_NAN2008) & 1) {
+ set_snan_bit_is_one(0, &env->active_fpu.fp_status);
+ } else {
+ set_snan_bit_is_one(1, &env->active_fpu.fp_status);
+ }
env->msair = env->cpu_model->MSAIR;
env->insn_flags = env->cpu_model->insn_flags;
diff --git a/target-mips/translate_init.c b/target-mips/translate_init.c
index 1094baa..bae6183 100644
--- a/target-mips/translate_init.c
+++ b/target-mips/translate_init.c
@@ -904,5 +904,6 @@ static void msa_reset(CPUMIPSState *env)
/* clear float_status nan mode */
set_default_nan_mode(0, &env->active_tc.msa_fp_status);
- set_snan_bit_is_one(1, &env->active_tc.msa_fp_status);
+ /* set proper signanling bit meaning ("1" means "quiet") */
+ set_snan_bit_is_one(0, &env->active_tc.msa_fp_status);
}
--
1.9.1
- [Qemu-ppc] [PATCH v5 4/9] target-mips: Amend processor definitions in relation to FCR31, (continued)
- [Qemu-ppc] [PATCH v5 4/9] target-mips: Amend processor definitions in relation to FCR31, Aleksandar Markovic, 2016/04/18
- [Qemu-ppc] [PATCH v5 2/9] softfloat: For Mips only, correct default NaN values, Aleksandar Markovic, 2016/04/18
- [Qemu-ppc] [PATCH v5 3/9] softfloat: For Mips only, correct order in pickNaNMulAdd(), Aleksandar Markovic, 2016/04/18
- [Qemu-ppc] [PATCH v5 6/9] target-mips: Add abs2008 flavor of <ABS|NEG>.<S|D>, Aleksandar Markovic, 2016/04/18
- [Qemu-ppc] [PATCH v5 8/9] target-mips: Clean up position and order of helpers for CVT.<L|W>.<S|D>, Aleksandar Markovic, 2016/04/18
- [Qemu-ppc] [PATCH v5 7/9] target-mips: Add nan2008 flavor of <CEIL|CVT|FLOOR|ROUND|TRUNC>.<L|W>.<S|D>, Aleksandar Markovic, 2016/04/18
- [Qemu-ppc] [PATCH v5 5/9] target-mips: Activate IEEE 274-2008 signaling NaN bit meaning,
Aleksandar Markovic <=
- Re: [Qemu-ppc] [PATCH v5 5/9] target-mips: Activate IEEE 274-2008 signaling NaN bit meaning, Leon Alrae, 2016/04/29
- [Qemu-ppc] [PATCH v5 9/9] target-mips: Clean up position of abs2008/nan2008 cases in genfarith(), Aleksandar Markovic, 2016/04/18
- [Qemu-ppc] [PATCH v5 1/9] softfloat: Implement run-time-configurable meaning of signaling NaN bit, Aleksandar Markovic, 2016/04/18