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 archHypot(p, q float64) float64
     8TEXT ·archHypot(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
    41not_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
    56is_inf:
    57	MOVL    AX, ret_hi+20(FP)  // return +Inf = 0x7FF0000000000000
    58	MOVL    $0x00000000, ret_lo+16(FP)
    59	RET
View as plain text