Text file src/pkg/math/exp2_386.s

     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 Exp2(x float64) float64
     8	TEXT ·Exp2(SB),NOSPLIT,$0
     9	// test bits for not-finite
    10		MOVL    x_hi+4(FP), AX
    11		ANDL    $0x7ff00000, AX
    12		CMPL    AX, $0x7ff00000
    13		JEQ     not_finite
    14		FMOVD   x+0(FP), F0   // F0=x
    15		FMOVD   F0, F1        // F0=x, F1=x
    16		FRNDINT               // F0=int(x), F1=x
    17		FSUBD   F0, F1        // F0=int(x), F1=x-int(x)
    18		FXCHD   F0, F1        // F0=x-int(x), F1=int(x)
    19		F2XM1                 // F0=2**(x-int(x))-1, F1=int(x)
    20		FLD1                  // F0=1, F1=2**(x-int(x))-1, F2=int(x)
    21		FADDDP  F0, F1        // F0=2**(x-int(x)), F1=int(x)
    22		FSCALE                // F0=2**x, F1=int(x)
    23		FMOVDP  F0, F1        // F0=2**x
    24		FMOVDP  F0, ret+8(FP)
    25		RET
    26	not_finite:
    27	// test bits for -Inf
    28		MOVL    x_hi+4(FP), BX
    29		MOVL    x_lo+0(FP), CX
    30		CMPL    BX, $0xfff00000
    31		JNE     not_neginf
    32		CMPL    CX, $0
    33		JNE     not_neginf
    34		MOVL    $0, ret_lo+8(FP)
    35		MOVL    $0, ret_hi+12(FP)
    36		RET
    37	not_neginf:
    38		MOVL    CX, ret_lo+8(FP)
    39		MOVL    BX, ret_hi+12(FP)
    40		RET

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