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Text file src/math/hypot_386.s

Documentation: math

     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 Hypot(p, q float64) float64
     8	TEXT ·Hypot(SB),NOSPLIT,$0
     9	// test bits for not-finite
    10		MOVL    p_hi+4(FP), AX   // high word p
    11		ANDL    $0x7ff00000, AX
    12		CMPL    AX, $0x7ff00000
    13		JEQ     not_finite
    14		MOVL    q_hi+12(FP), AX   // high word q
    15		ANDL    $0x7ff00000, AX
    16		CMPL    AX, $0x7ff00000
    17		JEQ     not_finite
    18		FMOVD   p+0(FP), F0  // F0=p
    19		FABS                 // F0=|p|
    20		FMOVD   q+8(FP), F0  // F0=q, F1=|p|
    21		FABS                 // F0=|q|, F1=|p|
    22		FUCOMI  F0, F1       // compare F0 to F1
    23		JCC     2(PC)        // jump if F0 >= F1
    24		FXCHD   F0, F1       // F0=|p| (larger), F1=|q| (smaller)
    25		FTST                 // compare F0 to 0
    26		FSTSW	AX
    27		ANDW    $0x4000, AX
    28		JNE     10(PC)       // jump if F0 = 0
    29		FXCHD   F0, F1       // F0=q (smaller), F1=p (larger)
    30		FDIVD   F1, F0       // F0=q(=q/p), F1=p
    31		FMULD   F0, F0       // F0=q*q, F1=p
    32		FLD1                 // F0=1, F1=q*q, F2=p
    33		FADDDP  F0, F1       // F0=1+q*q, F1=p
    34		FSQRT                // F0=sqrt(1+q*q), F1=p
    35		FMULDP  F0, F1       // F0=p*sqrt(1+q*q)
    36		FMOVDP  F0, ret+16(FP)
    37		RET
    38		FMOVDP  F0, F1       // F0=0
    39		FMOVDP  F0, ret+16(FP)
    40		RET
    41	not_finite:
    42	// test bits for -Inf or +Inf
    43		MOVL    p_hi+4(FP), AX  // high word p
    44		ORL     p_lo+0(FP), AX  // low word p
    45		ANDL    $0x7fffffff, AX
    46		CMPL    AX, $0x7ff00000
    47		JEQ     is_inf
    48		MOVL    q_hi+12(FP), AX  // high word q
    49		ORL     q_lo+8(FP), AX   // low word q
    50		ANDL    $0x7fffffff, AX
    51		CMPL    AX, $0x7ff00000
    52		JEQ     is_inf
    53		MOVL    $0x7ff80000, ret_hi+20(FP)  // return NaN = 0x7FF8000000000001
    54		MOVL    $0x00000001, ret_lo+16(FP)
    55		RET
    56	is_inf:
    57		MOVL    AX, ret_hi+20(FP)  // return +Inf = 0x7FF0000000000000
    58		MOVL    $0x00000000, ret_lo+16(FP)
    59		RET

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