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| author | Szabolcs Nagy <nsz@port70.net> | 2013-09-05 12:23:44 +0000 |
|---|---|---|
| committer | Szabolcs Nagy <nsz@port70.net> | 2013-09-05 12:23:44 +0000 |
| commit | 02343946215a7ae03634c6490abcc69da68df589 (patch) | |
| tree | fe6fc02037922375ec8ef1e52da576a3345beb54 /src/math/x86_64/exp2l.s | |
| parent | e5937885de3c8d493a9d2978aa46a771740c7458 (diff) | |
| download | musl-02343946215a7ae03634c6490abcc69da68df589.tar.gz musl-02343946215a7ae03634c6490abcc69da68df589.tar.xz musl-02343946215a7ae03634c6490abcc69da68df589.zip | |
math: fix expm1l on x86_64 (avoid underflow for large negative x)
copy the fix from i386: return -1 instead of exp2l(x)-1 when x <= -65
Diffstat (limited to 'src/math/x86_64/exp2l.s')
| -rw-r--r-- | src/math/x86_64/exp2l.s | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/src/math/x86_64/exp2l.s b/src/math/x86_64/exp2l.s index e7145881..0d6cd563 100644 --- a/src/math/x86_64/exp2l.s +++ b/src/math/x86_64/exp2l.s @@ -4,8 +4,18 @@ expm1l: fldt 8(%rsp) fldl2e fmulp + movl $0xc2820000,-4(%rsp) + flds -4(%rsp) + fucomp %st(1) + fnstsw %ax + sahf fld1 - fld %st(1) + jb 1f + # x*log2e <= -65, return -1 without underflow + fstp %st(1) + fchs + ret +1: fld %st(1) fabs fucom %st(1) fnstsw %ax |