On 17/10/26 02:58, Matt Turner wrote:
Two fixes for the exception status that qemu-alpha reports to code
built with gcc -mieee. I found both running glibc's math tests under
linux-user.
Patch 1 fixes 471d493047, which was meant to record masked exceptions
in the FPCR but had no effect for insns with software completion.
Without it FE_INEXACT is never set for -mieee code.
Patch 2 makes underflow match the hardware for a result that rounds up
to the smallest normal number. Alpha raises no underflow there and
softfloat does.
Patch 1 does not depend on patch 2.
Tested with linux-user only; system mode is untested.
glibc's math tests (make check subdirs=math), run under linux-user:
PASS FAIL XFAIL
master 1400 110 1
series 1510 0 1
Nearly all of the failures on master are 'Exception "Inexact" not
set'. The XFAIL is test-float32x-float64-div. On master it fails for
missing inexact; with the series it fails only the four
div_{upward,downward}_double cases that glibc expects to fail on
Alpha.
The tcg-alpha-linux-user suite has six failures (float_convs,
float_convd, float_madds and a plugin variant of each). They fail the
same way on master.
We need the float_* tests fixed to get this series merged, re-generate?
93/1938 tcg+tcg-alpha-linux-user - qemu:alpha-linux-user-float_convd
FAIL 0.03s exit status 1
< to single: f32(0x0.00000000000000000000p+0:0000000000) (UNDERFLOW
INEXACT )
< to int32: 0 (INEXACT )
< to int64: 0 (INEXACT )
< to uint32: 0 (INEXACT )
< to uint64: 0 (INEXACT )
---
> to single: f32(0x0.00000000000000000000p+0:0000000000) (UNDERFLOW )
> to int32: 0 (OK)
> to int64: 0 (OK)
> to uint32: 0 (OK)
> to uint64: 0 (OK)
870,874c870,874
...
Signed-off-by: Matt Turner <[email protected]>
---
Changes in v2:
- Patch 2: fold the underflow check into soft_to_fpcr_exc, which now
takes whether the delivered result is normal, instead of adding
soft_to_fpcr_exc_tiny.
- Patch 2: check float_flag_input_denormal_used for CONFIG_USER_ONLY
only.
- Link to v1:
https://lore.kernel.org/qemu-devel/[email protected]
---
Matt Turner (2):
target/alpha: Record masked exceptions in FPCR for /S insns
