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 "exp10f.s" 30 31#include "libm.h" 32 33 ENTRY(exp10f) 34 movl 4(%esp),%ecx / ecx <-- x 35 andl $0x7fffffff,%ecx / ecx <-- |x| 36 cmpl $0x3e9a209a,%ecx / Is |x| < log10(2)? 37 jbe .shortcut / If so, take a shortcut. 38 cmpl $0x7f800000,%ecx / |x| >= INF? 39 jae .not_finite / if so, x is not finite 40 flds 4(%esp) / push x (=arg) 41 42 subl $8,%esp / save RP and set round-to-64-bits 43 fstcw (%esp) 44 movw (%esp),%ax 45 movw %ax,4(%esp) 46 orw $0x0300,%ax 47 movw %ax,(%esp) 48 fldcw (%esp) 49 50 fldl2t / push log2(10) }NOT for xtndd_dbl 51 fmulp %st,%st(1) / z = x*log2(10) }NOT for xtndd_dbl 52 fld %st(0) / duplicate stack top 53 frndint / [z],z 54 fucom / z integral? 55 fstsw %ax 56 sahf 57 je .z_integral / branch if z integral 58 fxch / z, [z] 59 fsub %st(1),%st / z-[z], [z] 60 f2xm1 / 2**(z-[z])-1, [z] 61 fld1 / 1,2**(z-[z])-1, [z] 62 faddp %st,%st(1) / 2**(z-[z]), [z] 63 fscale / 2**z = 10**(arg), [z] 64 fstp %st(1) 65 66 fstcw (%esp) / restore old RP 67 movw (%esp),%dx 68 andw $0xfcff,%dx 69 movw 4(%esp),%cx 70 andw $0x0300,%cx 71 orw %dx,%cx 72 movw %cx,(%esp) 73 fldcw (%esp) 74 add $8,%esp 75 76 ret 77 78.z_integral: / here, z is integral 79 fstp %st(0) / ,z 80 fld1 / 1 = 2**0, z 81 fscale / 2**(0 + z) = 2**z = 10**(arg), z 82 fstp %st(1) / 10**(arg) 83 84 fstcw (%esp) / restore old RP 85 movw (%esp),%dx 86 andw $0xfcff,%dx 87 movw 4(%esp),%cx 88 andw $0x0300,%cx 89 orw %dx,%cx 90 movw %cx,(%esp) 91 fldcw (%esp) 92 add $8,%esp 93 94 ret 95 96.shortcut: 97 / Here, |x| < log10(2), so |z| = |x*log2(10)| < 1 98 / whence z is in f2xm1's domain. 99 flds 4(%esp) / push x (=arg) 100 fldl2t / push log2(10) }NOT for xtndd_dbl 101 fmulp %st,%st(1) / z = x*log2(10) }NOT for xtndd_dbl 102 f2xm1 / 2**z - 1 103 fld1 / 1,2**z - 1 104 faddp %st,%st(1) / 2**z = 10**x 105 ret 106 107.not_finite: 108 ja .NaN_or_pinf / branch if x is NaN 109 movl 4(%esp),%eax / eax <-- x 110 andl $0x80000000,%eax / here, x is infinite, but +/-? 111 jz .NaN_or_pinf / branch if x = +INF 112 fldz / Here, x = -inf, so return 0 113 ret 114 115.NaN_or_pinf: 116 / Here, x = NaN or +inf, so load x and return immediately. 117 flds 4(%esp) 118 fwait 119 ret 120 .align 4 121 SET_SIZE(exp10f) 122