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https://github.com/golang/go
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c007ce824d
Preparation was in CL 134570043. This CL contains only the effect of 'hg mv src/pkg/* src'. For more about the move, see golang.org/s/go14nopkg.
58 lines
1.8 KiB
ArmAsm
58 lines
1.8 KiB
ArmAsm
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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#include "textflag.h"
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// func Expm1(x float64) float64
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TEXT ·Expm1(SB),NOSPLIT,$0
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FLDLN2 // F0=log(2) = 1/log2(e) ~ 0.693147
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FMOVD x+0(FP), F0 // F0=x, F1=1/log2(e)
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FABS // F0=|x|, F1=1/log2(e)
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FUCOMPP F0, F1 // compare F0 to F1
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FSTSW AX
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SAHF
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JCC use_exp // jump if F0 >= F1
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FLDL2E // F0=log2(e)
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FMULD x+0(FP), F0 // F0=x*log2(e) (-1<F0<1)
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F2XM1 // F0=e**x-1 = 2**(x*log2(e))-1
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FMOVDP F0, ret+8(FP)
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RET
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use_exp:
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// test bits for not-finite
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MOVL x_hi+4(FP), AX
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ANDL $0x7ff00000, AX
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CMPL AX, $0x7ff00000
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JEQ not_finite
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FLDL2E // F0=log2(e)
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FMULD x+0(FP), F0 // F0=x*log2(e)
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FMOVD F0, F1 // F0=x*log2(e), F1=x*log2(e)
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FRNDINT // F0=int(x*log2(e)), F1=x*log2(e)
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FSUBD F0, F1 // F0=int(x*log2(e)), F1=x*log2(e)-int(x*log2(e))
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FXCHD F0, F1 // F0=x*log2(e)-int(x*log2(e)), F1=int(x*log2(e))
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F2XM1 // F0=2**(x*log2(e)-int(x*log2(e)))-1, F1=int(x*log2(e))
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FLD1 // F0=1, F1=2**(x*log2(e)-int(x*log2(e)))-1, F2=int(x*log2(e))
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FADDDP F0, F1 // F0=2**(x*log2(e)-int(x*log2(e))), F1=int(x*log2(e))
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FSCALE // F0=e**x, F1=int(x*log2(e))
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FMOVDP F0, F1 // F0=e**x
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FLD1 // F0=1, F1=e**x
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FSUBDP F0, F1 // F0=e**x-1
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FMOVDP F0, ret+8(FP)
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RET
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not_finite:
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// test bits for -Inf
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MOVL x_hi+4(FP), BX
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MOVL x_lo+0(FP), CX
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CMPL BX, $0xfff00000
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JNE not_neginf
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CMPL CX, $0
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JNE not_neginf
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FLD1 // F0=1
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FCHS // F0=-1
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FMOVDP F0, ret+8(FP)
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RET
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not_neginf:
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MOVL CX, ret_lo+8(FP)
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MOVL BX, ret_hi+12(FP)
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RET
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