log_s390x.s

Documentation: math

     1// Copyright 2017 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// Minimax polynomial approximations
     8DATA ·logrodataL21<> + 0(SB)/8, $-.499999999999999778E+00
     9DATA ·logrodataL21<> + 8(SB)/8, $0.333333333333343751E+00
    10DATA ·logrodataL21<> + 16(SB)/8, $-.250000000001606881E+00
    11DATA ·logrodataL21<> + 24(SB)/8, $0.199999999971603032E+00
    12DATA ·logrodataL21<> + 32(SB)/8, $-.166666663114122038E+00
    13DATA ·logrodataL21<> + 40(SB)/8, $-.125002923782692399E+00
    14DATA ·logrodataL21<> + 48(SB)/8, $0.111142014580396256E+00
    15DATA ·logrodataL21<> + 56(SB)/8, $0.759438932618934220E-01
    16DATA ·logrodataL21<> + 64(SB)/8, $0.142857144267212549E+00
    17DATA ·logrodataL21<> + 72(SB)/8, $-.993038938793590759E-01
    18DATA ·logrodataL21<> + 80(SB)/8, $-1.0
    19GLOBL ·logrodataL21<> + 0(SB), RODATA, $88
    20
    21// Constants
    22DATA ·logxminf<> + 0(SB)/8, $0xfff0000000000000
    23GLOBL ·logxminf<> + 0(SB), RODATA, $8
    24DATA ·logxnan<> + 0(SB)/8, $0x7ff8000000000000
    25GLOBL ·logxnan<> + 0(SB), RODATA, $8
    26DATA ·logx43f<> + 0(SB)/8, $0x43f0000000000000
    27GLOBL ·logx43f<> + 0(SB), RODATA, $8
    28DATA ·logxl2<> + 0(SB)/8, $0x3fda7aecbeba4e46
    29GLOBL ·logxl2<> + 0(SB), RODATA, $8
    30DATA ·logxl1<> + 0(SB)/8, $0x3ffacde700000000
    31GLOBL ·logxl1<> + 0(SB), RODATA, $8
    32
    33/* Input transform scale and add constants */
    34DATA ·logxm<> + 0(SB)/8, $0x3fc77604e63c84b1
    35DATA ·logxm<> + 8(SB)/8, $0x40fb39456ab53250
    36DATA ·logxm<> + 16(SB)/8, $0x3fc9ee358b945f3f
    37DATA ·logxm<> + 24(SB)/8, $0x40fb39418bf3b137
    38DATA ·logxm<> + 32(SB)/8, $0x3fccfb2e1304f4b6
    39DATA ·logxm<> + 40(SB)/8, $0x40fb393d3eda3022
    40DATA ·logxm<> + 48(SB)/8, $0x3fd0000000000000
    41DATA ·logxm<> + 56(SB)/8, $0x40fb393969e70000
    42DATA ·logxm<> + 64(SB)/8, $0x3fd11117aafbfe04
    43DATA ·logxm<> + 72(SB)/8, $0x40fb3936eaefafcf
    44DATA ·logxm<> + 80(SB)/8, $0x3fd2492af5e658b2
    45DATA ·logxm<> + 88(SB)/8, $0x40fb39343ff01715
    46DATA ·logxm<> + 96(SB)/8, $0x3fd3b50c622a43dd
    47DATA ·logxm<> + 104(SB)/8, $0x40fb39315adae2f3
    48DATA ·logxm<> + 112(SB)/8, $0x3fd56bbeea918777
    49DATA ·logxm<> + 120(SB)/8, $0x40fb392e21698552
    50GLOBL ·logxm<> + 0(SB), RODATA, $128
    51
    52// Log returns the natural logarithm of the argument.
    53//
    54// Special cases are:
    55//      Log(+Inf) = +Inf
    56//      Log(0) = -Inf
    57//      Log(x < 0) = NaN
    58//      Log(NaN) = NaN
    59// The algorithm used is minimax polynomial approximation using a table of
    60// polynomial coefficients determined with a Remez exchange algorithm.
    61
    62TEXT	·logAsm(SB), NOSPLIT, $0-16
    63	FMOVD	x+0(FP), F0
    64	MOVD	$·logrodataL21<>+0(SB), R9
    65	MOVH	$0x8006, R4
    66	LGDR	F0, R1
    67	MOVD	$0x3FF0000000000000, R6
    68	SRAD	$48, R1, R1
    69	MOVD	$0x40F03E8000000000, R8
    70	SUBW	R1, R4
    71	RISBGZ	$32, $59, $0, R4, R2
    72	RISBGN	$0, $15, $48, R2, R6
    73	RISBGN	$16, $31, $32, R2, R8
    74	MOVW	R1, R7
    75	CMPBGT	R7, $22, L17
    76	LTDBR	F0, F0
    77	MOVD	$·logx43f<>+0(SB), R1
    78	FMOVD	0(R1), F2
    79	BLEU	L3
    80	MOVH	$0x8005, R12
    81	MOVH	$0x8405, R0
    82	BR	L15
    83L7:
    84	LTDBR	F0, F0
    85	BLEU	L3
    86L15:
    87	FMUL	F2, F0
    88	LGDR	F0, R1
    89	SRAD	$48, R1, R1
    90	SUBW	R1, R0, R2
    91	SUBW	R1, R12, R3
    92	BYTE	$0x18	//lr	%r4,%r2
    93	BYTE	$0x42
    94	ANDW	$0xFFFFFFF0, R3
    95	ANDW	$0xFFFFFFF0, R2
    96	BYTE	$0x18	//lr	%r5,%r1
    97	BYTE	$0x51
    98	MOVW	R1, R7
    99	CMPBLE	R7, $22, L7
   100	RISBGN	$0, $15, $48, R3, R6
   101	RISBGN	$16, $31, $32, R2, R8
   102L2:
   103	MOVH	R5, R5
   104	MOVH	$0x7FEF, R1
   105	CMPW	R5, R1
   106	BGT	L1
   107	LDGR	R6, F2
   108	FMUL	F2, F0
   109	RISBGZ	$57, $59, $3, R4, R4
   110	FMOVD	80(R9), F2
   111	MOVD	$·logxm<>+0(SB), R7
   112	ADD	R7, R4
   113	FMOVD	72(R9), F4
   114	WORD	$0xED004000	//madb	%f2,%f0,0(%r4)
   115	BYTE	$0x20
   116	BYTE	$0x1E
   117	FMOVD	64(R9), F1
   118	FMOVD	F2, F0
   119	FMOVD	56(R9), F2
   120	WFMADB	V0, V2, V4, V2
   121	WFMDB	V0, V0, V6
   122	FMOVD	48(R9), F4
   123	WFMADB	V0, V2, V4, V2
   124	FMOVD	40(R9), F4
   125	WFMADB	V2, V6, V1, V2
   126	FMOVD	32(R9), F1
   127	WFMADB	V6, V4, V1, V4
   128	FMOVD	24(R9), F1
   129	WFMADB	V6, V2, V1, V2
   130	FMOVD	16(R9), F1
   131	WFMADB	V6, V4, V1, V4
   132	MOVD	$·logxl1<>+0(SB), R1
   133	FMOVD	8(R9), F1
   134	WFMADB	V6, V2, V1, V2
   135	FMOVD	0(R9), F1
   136	WFMADB	V6, V4, V1, V4
   137	FMOVD	8(R4), F1
   138	WFMADB	V0, V2, V4, V2
   139	LDGR	R8, F4
   140	WFMADB	V6, V2, V0, V2
   141	WORD	$0xED401000	//msdb	%f1,%f4,0(%r1)
   142	BYTE	$0x10
   143	BYTE	$0x1F
   144	MOVD	·logxl2<>+0(SB), R1
   145	WORD	$0xB3130001	//lcdbr	%f0,%f1
   146	LDGR	R1, F4
   147	WFMADB	V0, V4, V2, V0
   148L1:
   149	FMOVD	F0, ret+8(FP)
   150	RET
   151L3:
   152	LTDBR	F0, F0
   153	BEQ	L20
   154	BGE	L1
   155	BVS	L1
   156
   157	MOVD	$·logxnan<>+0(SB), R1
   158	FMOVD	0(R1), F0
   159	BR	L1
   160L20:
   161	MOVD	$·logxminf<>+0(SB), R1
   162	FMOVD	0(R1), F0
   163	FMOVD	F0, ret+8(FP)
   164	RET
   165L17:
   166	BYTE	$0x18	//lr	%r5,%r1
   167	BYTE	$0x51
   168	BR	L2
View as plain text