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 "exp2l.s" 30 31#include "libm.h" 32LIBM_ANSI_PRAGMA_WEAK(exp2l,function) 33#include "libm_synonyms.h" 34 35 ENTRY(exp2l) 36 movl 16(%rsp),%ecx / cx <--sign&bexp(x) 37 andl $0x7fff,%ecx / ecx <-- zero_xtnd(bexp(x)) 38 cmpl $0x3fff,%ecx / Is |x| <= 1? 39 jb .shortcut / If so, take a shortcut. 40 je .check_tail / |x| may be slightly > 1 41.general_case: / Here, |x| > 1 or x is NaN 42 cmpl $0x7fff,%ecx / bexp(|x|) = bexp(INF)? 43 je .not_finite / if so, x is not finite 44.finite_non_special: / Here, 1 < |x| < INF 45 fldt 8(%rsp) / push arg 46 fld %st(0) / duplicate stack top 47 frndint / [x],x 48 fucomi %st(1),%st / x integral? 49 je .x_integral / branch if x integral 50 fxch / x, [x] 51 fsub %st(1),%st / x-[x], [x] 52 f2xm1 / 2**(x-[x])-1, [x] 53 fld1 / 1,2**(x-[x])-1, [x] 54 faddp %st,%st(1) / 2**(x-[x]), [x] 55 fscale / 2**x = 2**(arg), [x] 56 fstp %st(1) 57 ret 58 59.x_integral: 60 fstp %st(0) / ,x 61 fld1 / 1 = 2**0, x 62 fscale / 2**(0 + x) = 2**x, x 63 fstp %st(1) / 2**x 64 ret 65 66.check_tail: 67 movl 12(%rsp),%ecx / ecx <-- hi_32(sgnfcnd(x)) 68 cmpl $0x80000000,%ecx / Is |x| <= 1? 69 ja .finite_non_special 70 movl 8(%rsp),%edx / edx <-- lo_32(sgnfcnd(x)) 71 cmpl $0x0,%edx / Is |x| slightly > 1? 72 ja .finite_non_special / branch if |x| slightly > 1 73.shortcut: 74 / Here, |x| < 1, 75 / whence x is in f2xm1's domain. 76 fldt 8(%rsp) / push x 77 f2xm1 / 2**x - 1 78 fld1 / 1,2**x - 1 79 faddp %st,%st(1) / 2**x 80 ret 81 82.not_finite: 83 movl 12(%rsp),%ecx / ecx <-- hi_32(sgnfcnd(x)) 84 cmpl $0x80000000,%ecx / hi_32(|x|) = hi_32(INF)? 85 jne .NaN_or_pinf / if not, x is NaN 86 movl 8(%rsp),%edx / edx <-- lo_32(x) 87 cmpl $0,%edx / lo_32(x) = 0? 88 jne .NaN_or_pinf / if not, x is NaN 89 movl 16(%rsp),%eax / ax <-- sign&bexp((x)) 90 andl $0x8000,%eax / here, x is infinite, but +/-? 91 jz .NaN_or_pinf / branch if x = +INF 92 fldz / Here, x = -inf, so return 0 93 ret 94 95.NaN_or_pinf: 96 / Here, x = NaN or +inf, so load x and return immediately. 97 fldt 8(%rsp) 98 ret 99 .align 16 100 SET_SIZE(exp2l) 101