[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PULL 02/21] softfloat: Handle default NaN mode after pickN
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PULL 02/21] softfloat: Handle default NaN mode after pickNaNMulAdd, not before |
Date: |
Thu, 10 May 2018 18:45:00 +0100 |
It is implementation defined whether a multiply-add of
(0,inf,qnan) or (inf,0,qnan) raises InvalidaOperation or
not, so we let the target-specific pickNaNMulAdd function
handle this. This means that we must do the "return the
default NaN in default NaN mode" check after the call,
not before. Correct the ordering, and restore the comment
from the old propagateFloat64MulAddNaN() that warned about
this corner case.
This fixes a regression from 2.11 for Arm guests where we would
incorrectly fail to set the Invalid flag for these cases.
Cc: address@hidden
Signed-off-by: Peter Maydell <address@hidden>
Reviewed-by: Richard Henderson <address@hidden>
Reviewed-by: Alex Bennée <address@hidden>
Tested-by: Alex Bennée <address@hidden>
Message-id: address@hidden
---
fpu/softfloat.c | 52 ++++++++++++++++++++++++++++---------------------
1 file changed, 30 insertions(+), 22 deletions(-)
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 70e0c40a1c..8401b37bd4 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -602,34 +602,42 @@ static FloatParts pick_nan(FloatParts a, FloatParts b,
float_status *s)
static FloatParts pick_nan_muladd(FloatParts a, FloatParts b, FloatParts c,
bool inf_zero, float_status *s)
{
+ int which;
+
if (is_snan(a.cls) || is_snan(b.cls) || is_snan(c.cls)) {
s->float_exception_flags |= float_flag_invalid;
}
- if (s->default_nan_mode) {
- a.cls = float_class_dnan;
- } else {
- switch (pickNaNMulAdd(is_qnan(a.cls), is_snan(a.cls),
- is_qnan(b.cls), is_snan(b.cls),
- is_qnan(c.cls), is_snan(c.cls),
- inf_zero, s)) {
- case 0:
- break;
- case 1:
- a = b;
- break;
- case 2:
- a = c;
- break;
- case 3:
- a.cls = float_class_dnan;
- return a;
- default:
- g_assert_not_reached();
- }
+ which = pickNaNMulAdd(is_qnan(a.cls), is_snan(a.cls),
+ is_qnan(b.cls), is_snan(b.cls),
+ is_qnan(c.cls), is_snan(c.cls),
+ inf_zero, s);
- a.cls = float_class_msnan;
+ if (s->default_nan_mode) {
+ /* Note that this check is after pickNaNMulAdd so that function
+ * has an opportunity to set the Invalid flag.
+ */
+ a.cls = float_class_dnan;
+ return a;
}
+
+ switch (which) {
+ case 0:
+ break;
+ case 1:
+ a = b;
+ break;
+ case 2:
+ a = c;
+ break;
+ case 3:
+ a.cls = float_class_dnan;
+ return a;
+ default:
+ g_assert_not_reached();
+ }
+ a.cls = float_class_msnan;
+
return a;
}
--
2.17.0
- [Qemu-devel] [PULL 00/21] target-arm queue, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 03/21] pc: simplify MachineClass::get_hotplug_handler handling, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 02/21] softfloat: Handle default NaN mode after pickNaNMulAdd, not before,
Peter Maydell <=
- [Qemu-devel] [PULL 01/21] hw/arm/iotkit.c: fix minor memory leak, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 07/21] atomic.h: Work around gcc spurious "unused value" warning, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 08/21] tcg: Introduce helpers for integer min/max, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 06/21] make sure that we aren't overwriting mc->get_hotplug_handler by accident, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 09/21] target/arm: Use new min/max expanders, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 10/21] target/xtensa: Use new min/max expanders, Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 05/21] arm/boot: split load_dtb() from arm_load_kernel(), Peter Maydell, 2018/05/10
- [Qemu-devel] [PULL 12/21] tcg: Use GEN_ATOMIC_HELPER_FN for opposite endian atomic add, Peter Maydell, 2018/05/10