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[Qemu-devel] [PATCH 07/12] ARM: Return correct result for float-to-integ
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH 07/12] ARM: Return correct result for float-to-integer conversion of NaN |
Date: |
Tue, 23 Nov 2010 18:53:46 +0000 |
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 <address@hidden>
---
target-arm/helper.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 44 insertions(+), 0 deletions(-)
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 996d40d..72ba314 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -2445,43 +2445,84 @@ float64 VFP_HELPER(sito, d)(float32 x, CPUState *env)
}
/* Float to integer conversion. */
+
+/* Helper routines to identify NaNs. Note that softfloat's
+ * floatxx_is_nan() actually only returns true for quiet NaNs.
+ * A NaN has an exponent field all 1s and a fraction field
+ * anything except all zeros. Conveniently we can detect this
+ * by masking out the sign bit and doing an unsigned comparison.
+ */
+static int float32_is_any_nan(float32 x)
+{
+ return ((float32_val(x) & ~(1 << 31)) > 0x7f800000UL);
+}
+
+static int float64_is_any_nan(float64 x)
+{
+ return ((float64_val(x) & ~(1ULL << 63)) > 0x7ff0000000000000ULL);
+}
+
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));
}
@@ -2508,6 +2549,9 @@ 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)); \
--
1.6.3.3
- [Qemu-devel] [PATCH 06/12] ARM: Fix sense of to_integer bit in Neon VCVT float/int conversion, (continued)
[Qemu-devel] [PATCH 01/12] target-arm: Add support for PKHxx in thumb2, Peter Maydell, 2010/11/23
[Qemu-devel] [PATCH 07/12] ARM: Return correct result for float-to-integer conversion of NaN,
Peter Maydell <=
[Qemu-devel] [PATCH 03/12] target-arm: Handle 'smc' as an undefined instruction, Peter Maydell, 2010/11/23