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| author | Ulrich Drepper <drepper@redhat.com> | 2008-04-11 19:32:37 +0000 |
|---|---|---|
| committer | Ulrich Drepper <drepper@redhat.com> | 2008-04-11 19:32:37 +0000 |
| commit | c1e6b459c874837a402c3c09d9fe7906e57d33e7 (patch) | |
| tree | b8b455c573095bd80108b044530389f2158153f8 /math | |
| parent | 22dca1ea77613162d597c7cb0729873619eaf5e0 (diff) | |
| download | glibc-c1e6b459c874837a402c3c09d9fe7906e57d33e7.tar.gz glibc-c1e6b459c874837a402c3c09d9fe7906e57d33e7.tar.xz glibc-c1e6b459c874837a402c3c09d9fe7906e57d33e7.zip | |
[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.inc | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/math/libm-test.inc b/math/libm-test.inc index a33a182857..b8a73ae1f6 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); |