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 2006 Sun Microsystems, Inc. All rights reserved. 26 * Use is subject to license terms. 27 */ 28 29 .file "exp2l.s" 30 31 #include "libm.h" 32 LIBM_ANSI_PRAGMA_WEAK(exp2l,function) 33 #include "libm_synonyms.h" 34 35 ENTRY(exp2l) 36 movl 12(%esp),%ecx / cx <--sign&bexp(x) 37 andl $0x00007fff,%ecx / ecx <-- zero_xtnd(bexp(x)) 38 cmpl $0x00003fff,%ecx / Is |x| <= 1? 39 jb .shortcut / If so, take a shortcut. 40 je .check_tail / |x| may be slightly > 1 41 cmpl $0x00007fff,%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 4(%esp) / push arg 45 fld %st(0) / duplicate stack top 46 frndint / [x],x 47 fucom / x integral? 48 fnstsw %ax 49 sahf 50 je .x_integral / branch if x integral 51 fxch / x, [x] 52 fsub %st(1),%st / x-[x], [x] 53 f2xm1 / 2**(x-[x])-1, [x] 54 fld1 / 1,2**(x-[x])-1, [x] 55 faddp %st,%st(1) / 2**(x-[x]), [x] 56 fscale / 2**x = 2**(arg), [x] 57 fstp %st(1) 58 ret 59 60 .x_integral: 61 fstp %st(0) / ,x 62 fld1 / 1 = 2**0, x 63 fscale / 2**(0 + x) = 2**x, x 64 fstp %st(1) / 2**x 65 ret 66 67 .check_tail: 68 movl 8(%esp),%ecx / ecx <-- hi_32(sgnfcnd(x)) 69 cmpl $0x80000000,%ecx / Is |x| <= 1? 70 ja .finite_non_special 71 movl 4(%esp),%edx / edx <-- lo_32(sgnfcnd(x)) 72 cmpl $0x00000000,%edx / Is |x| slightly > 1? 73 ja .finite_non_special / branch if |x| slightly > 1 74 .shortcut: 75 / Here, |x| < 1, 76 / whence x is in f2xm1's domain. 77 fldt 4(%esp) / push x 78 f2xm1 / 2**x - 1 79 fld1 / 1,2**x - 1 80 faddp %st,%st(1) / 2**x 81 ret 82 83 .not_finite: 84 movl 8(%esp),%ecx / ecx <-- hi_32(sgnfcnd(x)) 85 cmpl $0x80000000,%ecx / hi_32(|x|) = hi_32(INF)? 86 jne .NaN_or_pinf / if not, x is NaN 87 movl 4(%esp),%edx / edx <-- lo_32(x) 88 cmpl $0,%edx / lo_32(x) = 0? 89 jne .NaN_or_pinf / if not, x is NaN 90 movl 12(%esp),%eax / ax <-- sign&bexp((x)) 91 andl $0x00008000,%eax / here, x is infinite, but +/-? 92 jz .NaN_or_pinf / branch if x = +INF 93 fldz / Here, x = -inf, so return 0 94 ret 95 96 .NaN_or_pinf: 97 / Here, x = NaN or +inf, so load x and return immediately. 98 fldt 4(%esp) 99 ret 100 .align 4 101 SET_SIZE(exp2l)