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| author | Ondřej Surý <ondrej@sury.org> | 2011-09-13 13:13:40 +0200 |
|---|---|---|
| committer | Ondřej Surý <ondrej@sury.org> | 2011-09-13 13:13:40 +0200 |
| commit | 5ff4c17907d5b19510a62e08fd8d3b11e62b431d (patch) | |
| tree | c0650497e988f47be9c6f2324fa692a52dea82e1 /src/pkg/math/exp_386.s | |
| parent | 80f18fc933cf3f3e829c5455a1023d69f7b86e52 (diff) | |
| download | golang-upstream/60.tar.gz | |
Imported Upstream version 60upstream/60
Diffstat (limited to 'src/pkg/math/exp_386.s')
| -rw-r--r-- | src/pkg/math/exp_386.s | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/src/pkg/math/exp_386.s b/src/pkg/math/exp_386.s new file mode 100644 index 000000000..e0743e72a --- /dev/null +++ b/src/pkg/math/exp_386.s @@ -0,0 +1,39 @@ +// Copyright 2010 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// func Exp(x float64) float64 +TEXT ·Exp(SB),7,$0 +// test bits for not-finite + MOVL x+4(FP), AX + ANDL $0x7ff00000, AX + CMPL AX, $0x7ff00000 + JEQ not_finite + FLDL2E // F0=log2(e) + FMULD x+0(FP), F0 // F0=x*log2(e) + FMOVD F0, F1 // F0=x*log2(e), F1=x*log2(e) + FRNDINT // F0=int(x*log2(e)), F1=x*log2(e) + FSUBD F0, F1 // F0=int(x*log2(e)), F1=x*log2(e)-int(x*log2(e)) + FXCHD F0, F1 // F0=x*log2(e)-int(x*log2(e)), F1=int(x*log2(e)) + F2XM1 // F0=2**(x*log2(e)-int(x*log2(e)))-1, F1=int(x*log2(e)) + FLD1 // F0=1, F1=2**(x*log2(e)-int(x*log2(e)))-1, F2=int(x*log2(e)) + FADDDP F0, F1 // F0=2**(x*log2(e)-int(x*log2(e))), F1=int(x*log2(e)) + FSCALE // F0=e**x, F1=int(x*log2(e)) + FMOVDP F0, F1 // F0=e**x + FMOVDP F0, r+8(FP) + RET +not_finite: +// test bits for -Inf + MOVL x+4(FP), BX + MOVL x+0(FP), CX + CMPL BX, $0xfff00000 + JNE not_neginf + CMPL CX, $0 + JNE not_neginf + FLDZ // F0=0 + FMOVDP F0, r+8(FP) + RET +not_neginf: + MOVL CX, r+8(FP) + MOVL BX, r+12(FP) + RET |