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 "xpg6.h" 34 35 .data 36 .align 8 37two52: .long 0x0,0x43300000 / 2**52 38 39 ENTRY(ilogb) 40 movl 8(%esp),%eax / eax <-- hi_32(x) 41 andl $0x7fffffff,%eax / eax <-- hi_32(abs(x)) 42 testl $0x7ff00000,%eax / is bexp(x) 0? 43 jz .bexp_0 / jump if x is 0 or subnormal 44 / biased exponent is non-zero 45 cmpl $0x7ff00000,%eax / is bexp(x) 0x7ff? 46 jae .bexp_all_1 / jump if x is NaN or Inf 47 shrl $20,%eax / eax <-- bexp(x) 48 subl $1023,%eax / unbias exponent by 1023 49 ret 50 51.bexp_all_1: 52 movl $0x7fffffff,%eax / x is NaN or inf, so return 0x7fffffff 53 jmp 0f 54 55.bexp_0: 56 orl 4(%esp),%eax / test whether x is 0 57 jnz .ilogb_subnorm 58 movl $0x80000001,%eax / x is +/-0, so return 0x80000001 590: 60 PIC_SETUP(0) 61 PIC_G_LOAD(movzwl,__xpg6,ecx) 62 PIC_WRAPUP 63 andl $_C99SUSv3_ilogb_0InfNaN_raises_invalid,%ecx 64 cmpl $0,%ecx 65 je 1f 66 fldz 67 fdivp %st,%st(0) / raise invalid as per SUSv3 681: 69 ret 70 71.ilogb_subnorm: / subnormal input 72 fldl 4(%esp) / push x 73 PIC_SETUP(1) 74 fmull PIC_L(two52) / x*2**52 75 PIC_WRAPUP 76 subl $8,%esp / set up storage area 77 fstpl (%esp) / store x*2**52 in storage are 78 movl $0x7ff00000,%eax 79 andl 4(%esp),%eax 80 shrl $20,%eax / extract exponent of x*2**52 81 subl $1075,%eax / unbias it by 1075 (= 1023 + 52) 82 addl $8,%esp 83 ret 84 .align 4 85 SET_SIZE(ilogb) 86