Commit be53fa78 authored May 04, 2020 by Joseph Myers Committed by Richard Henderson May 15, 2020

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 <joseph@codesourcery.com>
Message-Id: <alpine.DEB.2.21.2005042338470.22972@digraph.polyomino.org.uk>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

parent 41602807

fpu/softfloat.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -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 {

tests/tcg/i386/test-i386-pseudo-denormal.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}