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authorUlrich Drepper <drepper@redhat.com>2008-04-11 19:32:37 +0000
committerUlrich Drepper <drepper@redhat.com>2008-04-11 19:32:37 +0000
commitc1e6b459c874837a402c3c09d9fe7906e57d33e7 (patch)
treeb8b455c573095bd80108b044530389f2158153f8 /math
parent22dca1ea77613162d597c7cb0729873619eaf5e0 (diff)
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[BZ4997]
* sysdeps/powerpc/powerpc32/fpu/s_lround.S (__lround): Fixed erroneous result when x is +/-nextafter(+/-0.5,-/+1) i.e. all 1's in the mantissa. * sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S (__llround): Likewise. Also account for when x is an odd number between 2^52 and 2^53-1. * sysdeps/powerpc/powerpc64/fpu/s_llround.S (__llround): Likewise. * sysdeps/powerpc/powerpc64/fpu/s_llroundf.S (__llroundf): Likewise. * math/libm-test.inc (lround_test, llround_test): Added test cases to detect aforementioned erroneous conditions.
Diffstat (limited to 'math')
-rw-r--r--math/libm-test.inc43
1 files changed, 43 insertions, 0 deletions
diff --git a/math/libm-test.inc b/math/libm-test.inc
index a33a182..b8a73ae 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -4300,6 +4300,17 @@ lround_test (void)
# endif
TEST_f_l (lround, 2097152.5, 2097153);
TEST_f_l (lround, -2097152.5, -2097153);
+ /* nextafter(0.5,-1) */
+ TEST_f_l (lround, 0x1.fffffffffffffp-2, 0);
+ /* nextafter(-0.5,1) */
+ TEST_f_l (lround, -0x1.fffffffffffffp-2, 0);
+#else
+ /* nextafter(0.5,-1) */
+ TEST_f_l (lround, 0x1.fffffp-2, 0);
+ /* nextafter(-0.5,1) */
+ TEST_f_l (lround, -0x1.fffffp-2, 0);
+ TEST_f_l (lround, 0x1.fffffep+23, 16777215);
+ TEST_f_l (lround, -0x1.fffffep+23, -16777215);
#endif
END (lround);
}
@@ -4359,8 +4370,40 @@ llround_test (void)
TEST_f_L (llround, 4294967295.5, 4294967296LL);
/* 0x200000000 */
TEST_f_L (llround, 8589934591.5, 8589934592LL);
+
+ /* nextafter(0.5,-1) */
+ TEST_f_L (llround, 0x1.fffffffffffffp-2, 0);
+ /* nextafter(-0.5,1) */
+ TEST_f_L (llround, -0x1.fffffffffffffp-2, 0);
+ /* On PowerPC an exponent of '52' is the largest incrementally
+ * representable sequence of whole-numbers in the 'double' range. We test
+ * lround to make sure that a guard bit set during the lround operation
+ * hasn't forced an erroneous shift giving us an incorrect result. The odd
+ * numbers between +-(2^52+1 and 2^53-1) are affected since they have the
+ * rightmost bit set. */
+ /* +-(2^52+1) */
+ TEST_f_L (llround, 0x1.0000000000001p+52,4503599627370497LL);
+ TEST_f_L (llround, -0x1.0000000000001p+52,-4503599627370497LL);
+ /* +-(2^53-1): Input is the last (positive and negative) incrementally
+ * representable whole-number in the 'double' range that might round
+ * erroneously. */
+ TEST_f_L (llround, 0x1.fffffffffffffp+52, 9007199254740991LL);
+ TEST_f_L (llround, -0x1.fffffffffffffp+52, -9007199254740991LL);
+#else
+ /* nextafter(0.5,-1) */
+ TEST_f_L (llround, 0x1.fffffep-2, 0);
+ /* nextafter(-0.5,1) */
+ TEST_f_L (llround, -0x1.fffffep-2, 0);
+ /* As above, on PowerPC an exponent of '23' is the largest incrementally
+ * representable sequence of whole-numbers in the 'float' range.
+ * Likewise, numbers between +-(2^23+1 and 2^24-1) are affected. */
+ TEST_f_L (llround, 0x1.000002p+23,8388609);
+ TEST_f_L (llround, -0x1.000002p+23,-8388609);
+ TEST_f_L (llround, 0x1.fffffep+23, 16777215);
+ TEST_f_L (llround, -0x1.fffffep+23, -16777215);
#endif
+
#ifdef TEST_LDOUBLE
/* The input can only be represented in long double. */
TEST_f_L (llround, 4503599627370495.5L, 4503599627370496LL);