| // 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. | |
| #include "textflag.h" | |
| // func Frexp(f float64) (frac float64, exp int) | |
| TEXT ·Frexp(SB),NOSPLIT,$0 | |
| FMOVD f+0(FP), F0 // F0=f | |
| FXAM | |
| FSTSW AX | |
| SAHF | |
| JNP nan_zero_inf | |
| JCS nan_zero_inf | |
| FXTRACT // F0=f (0<=f<1), F1=e | |
| FMULD $(0.5), F0 // F0=f (0.5<=f<1), F1=e | |
| FMOVDP F0, frac+8(FP) // F0=e | |
| FLD1 // F0=1, F1=e | |
| FADDDP F0, F1 // F0=e+1 | |
| FMOVLP F0, exp+16(FP) // (int=int32) | |
| RET | |
| nan_zero_inf: | |
| FMOVDP F0, frac+8(FP) // F0=e | |
| MOVL $0, exp+16(FP) // exp=0 | |
| RET |