diff options
Diffstat (limited to 'src/math/x86_64')
| -rw-r--r-- | src/math/x86_64/expl.s | 36 |
1 files changed, 17 insertions, 19 deletions
diff --git a/src/math/x86_64/expl.s b/src/math/x86_64/expl.s index 64c1c78e..740bc779 100644 --- a/src/math/x86_64/expl.s +++ b/src/math/x86_64/expl.s @@ -40,7 +40,7 @@ exp2l: mov %eax,-20(%rsp) xor %eax,%eax mov %eax,-24(%rsp) - flds -16(%rsp) + flds -16(%rsp) # 16380 fld %st(1) fabs fucom %st(1) @@ -48,7 +48,8 @@ exp2l: fstp %st(0) fstp %st(0) sahf - ja 2f + ja 3f # |x| > 16380 + jp 2f # x is nan (avoid invalid except in fistp) fld %st(0) fistpl -16(%rsp) fildl -16(%rsp) @@ -58,28 +59,25 @@ exp2l: add %eax,-16(%rsp) f2xm1 fld1 - faddp - fldt -24(%rsp) + faddp # 2^(x-rint(x)) + fldt -24(%rsp) # 2^rint(x) fmulp - fstp %st(1) +2: fstp %st(1) ret -2: fld %st(0) +3: fld %st(0) fstpt -24(%rsp) - mov -15(%rsp),%ah - and $0x7f,%ah - cmp $0x7f,%ah - jne 1f - decb -15(%rsp) - fstp %st(0) - fldt -24(%rsp) -1: fld %st(0) + fld1 + mov -15(%rsp),%ax + and $0x7fff,%ax + cmp $0x7fff,%ax + je 1f # x = +-inf + fld %st(1) frndint - fxch %st(1) - fsub %st(1) + fxch %st(2) + fsub %st(2) # st(0)=x-rint(x), st(1)=1, st(2)=rint(x) f2xm1 - fld1 - faddp - fscale + faddp # 2^(x-rint(x)) +1: fscale fstp %st(1) ret |