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