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 Modf(f float64) (int float64, frac float64) 8 TEXT Modf(SB),NOSPLIT,$0 9 // special case for f == -0.0 10 MOVL f_hi+4(FP), DX // high word 11 MOVL f_lo+0(FP), AX // low word 12 CMPL DX, $(1<<31) // beginning of -0.0 13 JNE notNegativeZero 14 CMPL AX, $0 // could be denormalized 15 JNE notNegativeZero 16 MOVL AX, int_lo+8(FP) 17 MOVL DX, int_hi+12(FP) 18 MOVL AX, frac_lo+16(FP) 19 MOVL DX, frac_hi+20(FP) 20 RET 21 notNegativeZero: 22 FMOVD f+0(FP), F0 // F0=f 23 FMOVD F0, F1 // F0=f, F1=f 24 FSTCW -2(SP) // save old Control Word 25 MOVW -2(SP), AX 26 ORW $0x0c00, AX // Rounding Control set to truncate 27 MOVW AX, -4(SP) // store new Control Word 28 FLDCW -4(SP) // load new Control Word 29 FRNDINT // F0=trunc(f), F1=f 30 FLDCW -2(SP) // load old Control Word 31 FSUBD F0, F1 // F0=trunc(f), F1=f-trunc(f) 32 FMOVDP F0, int+8(FP) // F0=f-trunc(f) 33 FMOVDP F0, frac+16(FP) 34 RET 35
