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[Qemu-devel] [V4 PATCH 04/22] softfloat: Fix float64_to_uint32
From: |
Tom Musta |
Subject: |
[Qemu-devel] [V4 PATCH 04/22] softfloat: Fix float64_to_uint32 |
Date: |
Wed, 18 Dec 2013 14:19:03 -0600 |
The float64_to_uint32 has several flaws:
- for numbers between 2**32 and 2**64, the inexact exception flag
may get incorrectly set. In this case, only the invalid flag
should be set.
test pattern: 425F81378DC0CD1F / 0x1.f81378dc0cd1fp+38
- for numbers between 2**63 and 2**64, incorrect results may
be produced:
test pattern: 43EAAF73F1F0B8BD / 0x1.aaf73f1f0b8bdp+63
This patch re-implements float64_to_uint32 to re-use the
float64_to_uint64 routine (instead of float64_to_int64). For the
saturation case, the inexact bit is explicitly cleared before raising
the invalid flag, provided that it was not previously set.
V4: Fixed handling of stickiness of the inexact bit per comments from
Peter Maydell.
This contribution can be licensed under either the softfloat-2a or -2b
license.
Signed-off-by: Tom Musta <address@hidden>
---
fpu/softfloat.c | 15 +++++++--------
1 files changed, 7 insertions(+), 8 deletions(-)
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 1b614ae..6110e28 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -6578,19 +6578,18 @@ uint_fast16_t float32_to_uint16_round_to_zero(float32 a
STATUS_PARAM)
uint32 float64_to_uint32( float64 a STATUS_PARAM )
{
- int64_t v;
+ uint64_t v;
uint32 res;
+ int old_exc_flags = get_float_exception_flags(status);
- v = float64_to_int64(a STATUS_VAR);
- if (v < 0) {
- res = 0;
- float_raise( float_flag_invalid STATUS_VAR);
- } else if (v > 0xffffffff) {
+ v = float64_to_uint64(a STATUS_VAR);
+ if (v > 0xffffffff) {
res = 0xffffffff;
- float_raise( float_flag_invalid STATUS_VAR);
} else {
- res = v;
+ return v;
}
+ set_float_exception_flags(old_exc_flags, status);
+ float_raise(float_flag_invalid STATUS_VAR);
return res;
}
--
1.7.1
- [Qemu-devel] [V4 PATCH 00/22] PowerPC VSX Stage 3, Tom Musta, 2013/12/18
- [Qemu-devel] [V4 PATCH 01/22] softfloat: Fix float64_to_uint64, Tom Musta, 2013/12/18
- [Qemu-devel] [V4 PATCH 03/22] softfloat: Fix float64_to_uint64_round_to_zero, Tom Musta, 2013/12/18
- [Qemu-devel] [V4 PATCH 02/22] softfloat: Add float32_to_uint64(), Tom Musta, 2013/12/18
- [Qemu-devel] [V4 PATCH 04/22] softfloat: Fix float64_to_uint32,
Tom Musta <=
- [Qemu-devel] [V4 PATCH 05/22] softfloat: Fix float64_to_uint32_round_to_zero, Tom Musta, 2013/12/18
- [Qemu-devel] [V4 PATCH 06/22] target-ppc: Add set_fprf Argument to fload_invalid_op_excp(), Tom Musta, 2013/12/18
- [Qemu-devel] [V4 PATCH 07/22] target-ppc: General Support for VSX Helpers, Tom Musta, 2013/12/18
- [Qemu-devel] [V4 PATCH 08/22] target-ppc: Add VSX ISA2.06 xadd/xsub Instructions, Tom Musta, 2013/12/18
- [Qemu-devel] [V4 PATCH 09/22] target-ppc: Add VSX ISA2.06 xmul Instructions, Tom Musta, 2013/12/18
- [Qemu-devel] [V4 PATCH 10/22] target-ppc: Add VSX ISA2.06 xdiv Instructions, Tom Musta, 2013/12/18
- [Qemu-devel] [V4 PATCH 11/22] target-ppc: Add VSX ISA2.06 xre Instructions, Tom Musta, 2013/12/18
- [Qemu-devel] [V4 PATCH 12/22] target-ppc: Add VSX ISA2.06 xsqrt Instructions, Tom Musta, 2013/12/18