From be53fa785ab766d2722628403edee75b3e6ab599 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Mon, 4 May 2020 23:39:39 +0000 Subject: [PATCH] softfloat: fix floatx80 pseudo-denormal comparisons 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 Message-Id: Signed-off-by: Richard Henderson --- 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; }