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[PULL 3/4] softfloat: fix floatx80 pseudo-denormal comparisons
From: |
Richard Henderson |
Subject: |
[PULL 3/4] softfloat: fix floatx80 pseudo-denormal comparisons |
Date: |
Fri, 15 May 2020 11:47:21 -0700 |
From: Joseph Myers <address@hidden>
The softfloat floatx80 comparisons fail to allow for pseudo-denormals,
which should compare equal to corresponding values with biased
exponent 1 rather than 0. Add an adjustment for that case when
comparing numbers with the same sign.
Signed-off-by: Joseph Myers <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Richard Henderson <address@hidden>
---
fpu/softfloat.c | 7 +++++++
tests/tcg/i386/test-i386-pseudo-denormal.c | 4 ++++
2 files changed, 11 insertions(+)
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 6094d267b5..c57f72e3a6 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -7966,6 +7966,13 @@ static inline int floatx80_compare_internal(floatx80 a,
floatx80 b,
return 1 - (2 * aSign);
}
} else {
+ /* Normalize pseudo-denormals before comparison. */
+ if ((a.high & 0x7fff) == 0 && a.low & UINT64_C(0x8000000000000000)) {
+ ++a.high;
+ }
+ if ((b.high & 0x7fff) == 0 && b.low & UINT64_C(0x8000000000000000)) {
+ ++b.high;
+ }
if (a.low == b.low && a.high == b.high) {
return float_relation_equal;
} else {
diff --git a/tests/tcg/i386/test-i386-pseudo-denormal.c
b/tests/tcg/i386/test-i386-pseudo-denormal.c
index cfa2a500b0..acf2b9cf03 100644
--- a/tests/tcg/i386/test-i386-pseudo-denormal.c
+++ b/tests/tcg/i386/test-i386-pseudo-denormal.c
@@ -20,5 +20,9 @@ int main(void)
printf("FAIL: pseudo-denormal add\n");
ret = 1;
}
+ if (ld_pseudo_m16382.ld != 0x1p-16382L) {
+ printf("FAIL: pseudo-denormal compare\n");
+ ret = 1;
+ }
return ret;
}
--
2.20.1
- [PULL 0/4] softfloat patch queue, Richard Henderson, 2020/05/15
- [PULL 1/4] softfloat: silence sNaN for conversions to/from floatx80, Richard Henderson, 2020/05/15
- [PULL 2/4] softfloat: fix floatx80 pseudo-denormal addition / subtraction, Richard Henderson, 2020/05/15
- [PULL 4/4] softfloat: fix floatx80 pseudo-denormal round to integer, Richard Henderson, 2020/05/15
- [PULL 3/4] softfloat: fix floatx80 pseudo-denormal comparisons,
Richard Henderson <=
- Re: [PULL 0/4] softfloat patch queue, Peter Maydell, 2020/05/15
- Re: [PULL 0/4] softfloat patch queue, no-reply, 2020/05/16