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| author | Alexander Monakov <amonakov@ispras.ru> | 2020-01-07 15:53:03 +0300 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2020-03-24 16:31:36 -0400 |
| commit | acfe6d033eafe12d61ad91f496850b1bf58c6f98 (patch) | |
| tree | 7c448f0aeee5bee6241b4ac291ce57ffb35db0ee /src/math/i386 | |
| parent | 29adaeb2c0e795e75044a9b678b8cc66570f7e95 (diff) | |
| download | musl-acfe6d033eafe12d61ad91f496850b1bf58c6f98.tar.gz musl-acfe6d033eafe12d61ad91f496850b1bf58c6f98.tar.xz musl-acfe6d033eafe12d61ad91f496850b1bf58c6f98.zip | |
math: move i386 sqrt to C with inline asm
Diffstat (limited to 'src/math/i386')
| -rw-r--r-- | src/math/i386/sqrt.c | 15 | ||||
| -rw-r--r-- | src/math/i386/sqrt.s | 21 |
2 files changed, 15 insertions, 21 deletions
diff --git a/src/math/i386/sqrt.c b/src/math/i386/sqrt.c new file mode 100644 index 00000000..934fbcca --- /dev/null +++ b/src/math/i386/sqrt.c @@ -0,0 +1,15 @@ +#include "libm.h" + +double sqrt(double x) +{ + union ldshape ux; + unsigned fpsr; + __asm__ ("fsqrt; fnstsw %%ax": "=t"(ux.f), "=a"(fpsr) : "0"(x)); + if ((ux.i.m & 0x7ff) != 0x400) + return (double)ux.f; + /* Rounding to double would have encountered an exact halfway case. + Adjust mantissa downwards if fsqrt rounded up, else upwards. + (result of fsqrt could not have been exact) */ + ux.i.m ^= (fpsr & 0x200) + 0x300; + return (double)ux.f; +} diff --git a/src/math/i386/sqrt.s b/src/math/i386/sqrt.s deleted file mode 100644 index 57837e25..00000000 --- a/src/math/i386/sqrt.s +++ /dev/null @@ -1,21 +0,0 @@ -.global sqrt -.type sqrt,@function -sqrt: fldl 4(%esp) - fsqrt - fnstsw %ax - sub $12,%esp - fld %st(0) - fstpt (%esp) - mov (%esp),%ecx - and $0x7ff,%ecx - cmp $0x400,%ecx - jnz 1f - and $0x200,%eax - sub $0x100,%eax - sub %eax,(%esp) - fstp %st(0) - fldt (%esp) -1: add $12,%esp - fstpl 4(%esp) - fldl 4(%esp) - ret |