[PULL 08/17] fpu: Fix unexpected exception flags when converting infinity to OCP E4M3

alistair23@gmail.com posted 17 patches 2 days, 14 hours ago
Maintainers: Pierrick Bouvier <pierrick.bouvier@linaro.org>, Aurelien Jarno <aurelien@aurel32.net>, Peter Maydell <peter.maydell@linaro.org>, "Alex Bennée" <alex.bennee@linaro.org>, Alistair Francis <Alistair.Francis@wdc.com>, Palmer Dabbelt <palmer@dabbelt.com>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Weiwei Li <liwei1518@gmail.com>, Daniel Henrique Barboza <daniel.barboza@oss.qualcomm.com>, Liu Zhiwei <zhiwei_liu@linux.alibaba.com>, Chao Liu <chao.liu.zevorn@gmail.com>
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[PULL 08/17] fpu: Fix unexpected exception flags when converting infinity to OCP E4M3
Posted by alistair23@gmail.com 2 days, 14 hours ago
From: Max Chou <max.chou@sifive.com>

Infinity is a special case distinct from numeric overflow:
- Numeric overflow: finite value exceeds format's max normal
  -> overflow|inexact
- Infinity conversion: input is already infinite
  -> no flags

This commit fixes the unexpect exception flags by relocating the float
exception flag update flow to be outside the uncanon_e4m3_overflow.
And raising the overflow|inexact for numeric overflow in uncanon_normal.

Fixes: 27e989f99c ("fpu: Add conversion routines for OCP FP8 E4M3")
Reviewed-by: Chao Liu <chao.liu.zevorn@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Max Chou <max.chou@sifive.com>
Message-ID: <20260226071817.1417875-3-max.chou@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 fpu/softfloat-parts.c.inc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index a738758aee..3c323c0cec 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -277,7 +277,6 @@ static void partsN(uncanon_e4m3_overflow)(FloatPartsN *p, float_status *s,
                                           const FloatFmt *fmt, bool saturate)
 {
     assert(N == 64);
-    float_raise(float_flag_overflow | float_flag_inexact, s);
     if (saturate) {
         p->exp = fmt->exp_max;
         p->frac_hi = E4M3_NORMAL_FRAC_MAX;
@@ -388,6 +387,7 @@ static void partsN(uncanon_normal)(FloatPartsN *p, float_status *s,
                 if (exp > exp_max || p->frac_hi > E4M3_NORMAL_FRAC_MAX) {
                     partsN(uncanon_e4m3_overflow)(p, s, fmt, overflow_norm);
                     exp = p->exp;
+                    flags |= (float_flag_overflow | float_flag_inexact);
                 }
                 break;
 
-- 
2.53.0