1 // Copyright 2010 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 #include "textflag.h" 6 7 // func Frexp(f float64) (frac float64, exp int) 8 TEXT Frexp(SB),NOSPLIT,$0 9 FMOVD f+0(FP), F0 // F0=f 10 FXAM 11 FSTSW AX 12 SAHF 13 JNP nan_zero_inf 14 JCS nan_zero_inf 15 FXTRACT // F0=f (0<=f<1), F1=e 16 FMULD $(0.5), F0 // F0=f (0.5<=f<1), F1=e 17 FMOVDP F0, frac+8(FP) // F0=e 18 FLD1 // F0=1, F1=e 19 FADDDP F0, F1 // F0=e+1 20 FMOVLP F0, exp+16(FP) // (int=int32) 21 RET 22 nan_zero_inf: 23 FMOVDP F0, frac+8(FP) // F0=e 24 MOVL $0, exp+16(FP) // exp=0 25 RET 26
