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author | Joseph Myers <joseph@codesourcery.com> | 2015-02-13 21:54:44 +0000 |
---|---|---|
committer | Joseph Myers <joseph@codesourcery.com> | 2015-02-13 21:54:44 +0000 |
commit | d9afe48d55a412e76b0dcb28335fd4b390fe07ae (patch) | |
tree | cebb0e3a23be3a2e930fef5b8ed43d0d83a2d265 /sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c | |
parent | 3846188b21eaae3fc57e399a9aead34847521bbb (diff) | |
download | glibc-d9afe48d55a412e76b0dcb28335fd4b390fe07ae.tar.gz glibc-d9afe48d55a412e76b0dcb28335fd4b390fe07ae.tar.xz glibc-d9afe48d55a412e76b0dcb28335fd4b390fe07ae.zip |
Fix dbl-64/wordsize-64 remquo (bug 17569).
The dbl-64/wordsize-64 remquo implementation follows similar logic to various other implementations, but where that logic computes some absolute values, it wrongly uses a previously computed bit-pattern for the absolute value of the first argument, where actually it needs the absolute value of the first argument mod 8 times the second. This patch fixes it to compute the correct absolute value. The integer quotient result of remquo is only specified mod 8 (including its sign); architecture-specific versions may well vary in what results they give for higher bits of that result (and indeed bug 17569 gives an example correct result from __builtin_remquo giving 9 for that result, where the particular glibc implementation used in that bug report would give 1 after this fix). Thus, this patch adapts the tests of remquo to test that result only mod 8, to allow for such variation when tests with higher quotient are included. Tested for x86_64 and x86. [BZ #17569] * sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c (__remquo): Compute absolute value of x as modified by fmod, not original value of x. * math/libm-test.inc (RUN_TEST_ffI_f1): Rename to RUN_TEST_ffI_f1_mod8. Check extra return value mod 8. (RUN_TEST_LOOP_ffI_f1): Rename to RUN_TEST_LOOP_ffI_f1_mod8. Call RUN_TEST_ffI_f1_mod8. (remquo_test_data): Add more tests.
Diffstat (limited to 'sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c')
-rw-r--r-- | sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c index 36fc37c134..5b7142576a 100644 --- a/sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c +++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c @@ -55,7 +55,7 @@ __remquo (double x, double y, int *quo) return zero * x; } - INSERT_WORDS64 (x, hx); + x = fabs (x); INSERT_WORDS64 (y, hy); cquo = 0; |