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 "ilogb.s" 30 31#include "libm.h" 32LIBM_ANSI_PRAGMA_WEAK(ilogb,function) 33#include "libm_synonyms.h" 34#include "xpg6.h" 35 36 .data 37 .align 8 38two52: .long 0x0,0x43300000 / 2**52 39 40 ENTRY(ilogb) 41 movl 8(%esp),%eax / eax <-- hi_32(x) 42 andl $0x7fffffff,%eax / eax <-- hi_32(abs(x)) 43 testl $0x7ff00000,%eax / is bexp(x) 0? 44 jz .bexp_0 / jump if x is 0 or subnormal 45 / biased exponent is non-zero 46 cmpl $0x7ff00000,%eax / is bexp(x) 0x7ff? 47 jae .bexp_all_1 / jump if x is NaN or Inf 48 shrl $20,%eax / eax <-- bexp(x) 49 subl $1023,%eax / unbias exponent by 1023 50 ret 51 52.bexp_all_1: 53 movl $0x7fffffff,%eax / x is NaN or inf, so return 0x7fffffff 54 jmp 0f 55 56.bexp_0: 57 orl 4(%esp),%eax / test whether x is 0 58 jnz .ilogb_subnorm 59 movl $0x80000001,%eax / x is +/-0, so return 0x80000001 600: 61 PIC_SETUP(0) 62 PIC_G_LOAD(movzwl,__xpg6,ecx) 63 PIC_WRAPUP 64 andl $_C99SUSv3_ilogb_0InfNaN_raises_invalid,%ecx 65 cmpl $0,%ecx 66 je 1f 67 fldz 68 fdivp %st,%st(0) / raise invalid as per SUSv3 691: 70 ret 71 72.ilogb_subnorm: / subnormal input 73 fldl 4(%esp) / push x 74 PIC_SETUP(1) 75 fmull PIC_L(two52) / x*2**52 76 PIC_WRAPUP 77 subl $8,%esp / set up storage area 78 fstpl (%esp) / store x*2**52 in storage are 79 movl $0x7ff00000,%eax 80 andl 4(%esp),%eax 81 shrl $20,%eax / extract exponent of x*2**52 82 subl $1075,%eax / unbias it by 1075 (= 1023 + 52) 83 addl $8,%esp 84 ret 85 .align 4 86 SET_SIZE(ilogb) 87