Patchwork [05/10] ARM: Return correct result for float-to-integer conversion of NaN

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Submitter Peter Maydell
Date Dec. 6, 2010, 5 p.m.
Message ID <1291654811-29863-6-git-send-email-peter.maydell@linaro.org>
Download mbox | patch
Permalink /patch/74412/
State New
Headers show

Comments

Peter Maydell - Dec. 6, 2010, 5 p.m.
The ARM architecture mandates that converting a NaN value to
integer gives zero (if Invalid Operation FP exceptions are
not being trapped). This isn't the behaviour of the SoftFloat
library, so NaNs must be special-cased.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target-arm/helper.c |   27 +++++++++++++++++++++++++++
 1 files changed, 27 insertions(+), 0 deletions(-)
Nathan Froyd - Dec. 6, 2010, 6:18 p.m.
On Mon, Dec 06, 2010 at 05:00:06PM +0000, Peter Maydell wrote:
> The ARM architecture mandates that converting a NaN value to
> integer gives zero (if Invalid Operation FP exceptions are
> not being trapped). This isn't the behaviour of the SoftFloat
> library, so NaNs must be special-cased.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Nathan Froyd <froydnj@codesourcery.com>

-Nathan

Patch

diff --git a/target-arm/helper.c b/target-arm/helper.c
index 2a1f448..6d2a8f2 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -2463,41 +2463,65 @@  float64 VFP_HELPER(sito, d)(float32 x, CPUState *env)
 /* Float to integer conversion.  */
 float32 VFP_HELPER(toui, s)(float32 x, CPUState *env)
 {
+    if (float32_is_any_nan(x)) {
+        return float32_zero;
+    }
     return vfp_itos(float32_to_uint32(x, &env->vfp.fp_status));
 }
 
 float32 VFP_HELPER(toui, d)(float64 x, CPUState *env)
 {
+    if (float64_is_any_nan(x)) {
+        return float32_zero;
+    }
     return vfp_itos(float64_to_uint32(x, &env->vfp.fp_status));
 }
 
 float32 VFP_HELPER(tosi, s)(float32 x, CPUState *env)
 {
+    if (float32_is_any_nan(x)) {
+        return float32_zero;
+    }
     return vfp_itos(float32_to_int32(x, &env->vfp.fp_status));
 }
 
 float32 VFP_HELPER(tosi, d)(float64 x, CPUState *env)
 {
+    if (float64_is_any_nan(x)) {
+        return float32_zero;
+    }
     return vfp_itos(float64_to_int32(x, &env->vfp.fp_status));
 }
 
 float32 VFP_HELPER(touiz, s)(float32 x, CPUState *env)
 {
+    if (float32_is_any_nan(x)) {
+        return float32_zero;
+    }
     return vfp_itos(float32_to_uint32_round_to_zero(x, &env->vfp.fp_status));
 }
 
 float32 VFP_HELPER(touiz, d)(float64 x, CPUState *env)
 {
+    if (float64_is_any_nan(x)) {
+        return float32_zero;
+    }
     return vfp_itos(float64_to_uint32_round_to_zero(x, &env->vfp.fp_status));
 }
 
 float32 VFP_HELPER(tosiz, s)(float32 x, CPUState *env)
 {
+    if (float32_is_any_nan(x)) {
+        return float32_zero;
+    }
     return vfp_itos(float32_to_int32_round_to_zero(x, &env->vfp.fp_status));
 }
 
 float32 VFP_HELPER(tosiz, d)(float64 x, CPUState *env)
 {
+    if (float64_is_any_nan(x)) {
+        return float32_zero;
+    }
     return vfp_itos(float64_to_int32_round_to_zero(x, &env->vfp.fp_status));
 }
 
@@ -2524,6 +2548,9 @@  ftype VFP_HELPER(name##to, p)(ftype x, uint32_t shift, CPUState *env) \
 ftype VFP_HELPER(to##name, p)(ftype x, uint32_t shift, CPUState *env) \
 { \
     ftype tmp; \
+    if (ftype##_is_any_nan(x)) { \
+        return ftype##_zero; \
+    } \
     tmp = ftype##_scalbn(x, shift, &env->vfp.fp_status); \
     return vfp_ito##p((itype)ftype##_to_##sign##int32_round_to_zero(tmp, \
         &env->vfp.fp_status)); \