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| // 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 Exp2(x float64) float64
| TEXT ·Exp2(SB),NOSPLIT,$0
| // test bits for not-finite
| MOVL x_hi+4(FP), AX
| ANDL $0x7ff00000, AX
| CMPL AX, $0x7ff00000
| JEQ not_finite
| FMOVD x+0(FP), F0 // F0=x
| FMOVD F0, F1 // F0=x, F1=x
| FRNDINT // F0=int(x), F1=x
| FSUBD F0, F1 // F0=int(x), F1=x-int(x)
| FXCHD F0, F1 // F0=x-int(x), F1=int(x)
| F2XM1 // F0=2**(x-int(x))-1, F1=int(x)
| FLD1 // F0=1, F1=2**(x-int(x))-1, F2=int(x)
| FADDDP F0, F1 // F0=2**(x-int(x)), F1=int(x)
| FSCALE // F0=2**x, F1=int(x)
| FMOVDP F0, F1 // F0=2**x
| FMOVDP F0, ret+8(FP)
| RET
| not_finite:
| // test bits for -Inf
| MOVL x_hi+4(FP), BX
| MOVL x_lo+0(FP), CX
| CMPL BX, $0xfff00000
| JNE not_neginf
| CMPL CX, $0
| JNE not_neginf
| MOVL $0, ret_lo+8(FP)
| MOVL $0, ret_hi+12(FP)
| RET
| not_neginf:
| MOVL CX, ret_lo+8(FP)
| MOVL BX, ret_hi+12(FP)
| RET
|
|
