1/* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21/* 22 * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 23 */ 24/* 25 * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 26 * Use is subject to license terms. 27 */ 28 29 .file "exp10.s" 30 31#include "libm.h" 32 33 ENTRY(exp10) 34 movl 8(%esp),%ecx / ecx <-- hi_32(x) 35 andl $0x7fffffff,%ecx / ecx <-- hi_32(|x|) 36 cmpl $0x3fd34413,%ecx / Is |x| < log10(2)? 37 jb .shortcut / If so, take a shortcut. 38 je .check_tail / maybe |x| only slightly < log10(2) 39 cmpl $0x7ff00000,%ecx / hi_32(|x|) >= hi_32(INF)? 40 jae .not_finite / if so, x is not finite 41.finite_non_special: / Here, log10(2) < |x| < INF 42 fldl 4(%esp) / push x (=arg) 43 44 subl $8,%esp / save RP and set round-to-64-bits 45 fstcw (%esp) 46 movw (%esp),%ax 47 movw %ax,4(%esp) 48 orw $0x0300,%ax 49 movw %ax,(%esp) 50 fldcw (%esp) 51 52 fldl2t / push log2(10) }NOT for xtndd_dbl 53 fmulp %st,%st(1) / z = x*log2(10) }NOT for xtndd_dbl 54 fld %st(0) / duplicate stack top 55 frndint / [z],z 56 fucom / z integral? 57 fstsw %ax 58 sahf 59 je .z_integral / branch if z integral 60 fxch / z, [z] 61 fsub %st(1),%st / z-[z], [z] 62 f2xm1 / 2**(z-[z])-1, [z] 63 fld1 / 1,2**(z-[z])-1, [z] 64 faddp %st,%st(1) / 2**(z-[z]), [z] 65 fscale / 2**z = 10**(arg), [z] 66 fstp %st(1) 67 68 fstcw (%esp) / restore old RP 69 movw (%esp),%dx 70 andw $0xfcff,%dx 71 movw 4(%esp),%cx 72 andw $0x0300,%cx 73 orw %dx,%cx 74 movw %cx,(%esp) 75 fldcw (%esp) 76 add $8,%esp 77 78 ret 79 80.z_integral: / here, z is integral 81 fstp %st(0) / ,z 82 fld1 / 1 = 2**0, z 83 fscale / 2**(0 + z) = 2**z = 10**(arg), z 84 fstp %st(1) / 10**(arg) 85 86 fstcw (%esp) / restore old RP 87 movw (%esp),%dx 88 andw $0xfcff,%dx 89 movw 4(%esp),%cx 90 andw $0x0300,%cx 91 orw %dx,%cx 92 movw %cx,(%esp) 93 fldcw (%esp) 94 add $8,%esp 95 96 ret 97 98.check_tail: 99 movl 4(%esp),%edx / edx <-- lo_32(x) 100 cmpl $0x509f79fe,%edx / Is |x| slightly > log10(2)? 101 ja .finite_non_special / branch if |x| slightly > log10(2) 102.shortcut: 103 / Here, |x| < log10(2), so |z| = |x*log2(10)| < 1 104 / whence z is in f2xm1's domain. 105 fldl 4(%esp) / push x (=arg) 106 fldl2t / push log2(10) }NOT for xtndd_dbl 107 fmulp %st,%st(1) / z = x*log2(10) }NOT for xtndd_dbl 108 f2xm1 / 2**z - 1 109 fld1 / 1,2**z - 1 110 faddp %st,%st(1) / 2**z = 10**x 111 ret 112 113.not_finite: 114 cmpl $0x7ff00000,%ecx / hi_32(|x|) > hi_32(INF)? 115 ja .NaN_or_pinf / if so, x is NaN 116 movl 4(%esp),%edx / edx <-- lo_32(x) 117 cmpl $0,%edx / lo_32(x) = 0? 118 jne .NaN_or_pinf / if not, x is NaN 119 movl 8(%esp),%eax / eax <-- hi_32(x) 120 andl $0x80000000,%eax / here, x is infinite, but +/-? 121 jz .NaN_or_pinf / branch if x = +INF 122 fldz / Here, x = -inf, so return 0 123 ret 124 125.NaN_or_pinf: 126 / Here, x = NaN or +inf, so load x and return immediately. 127 fldl 4(%esp) 128 fwait 129 ret 130 .align 4 131 SET_SIZE(exp10) 132