1*5b2ba9d3SPiotr Jasiukajtis/* 2*5b2ba9d3SPiotr Jasiukajtis * CDDL HEADER START 3*5b2ba9d3SPiotr Jasiukajtis * 4*5b2ba9d3SPiotr Jasiukajtis * The contents of this file are subject to the terms of the 5*5b2ba9d3SPiotr Jasiukajtis * Common Development and Distribution License (the "License"). 6*5b2ba9d3SPiotr Jasiukajtis * You may not use this file except in compliance with the License. 7*5b2ba9d3SPiotr Jasiukajtis * 8*5b2ba9d3SPiotr Jasiukajtis * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9*5b2ba9d3SPiotr Jasiukajtis * or http://www.opensolaris.org/os/licensing. 10*5b2ba9d3SPiotr Jasiukajtis * See the License for the specific language governing permissions 11*5b2ba9d3SPiotr Jasiukajtis * and limitations under the License. 12*5b2ba9d3SPiotr Jasiukajtis * 13*5b2ba9d3SPiotr Jasiukajtis * When distributing Covered Code, include this CDDL HEADER in each 14*5b2ba9d3SPiotr Jasiukajtis * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15*5b2ba9d3SPiotr Jasiukajtis * If applicable, add the following below this CDDL HEADER, with the 16*5b2ba9d3SPiotr Jasiukajtis * fields enclosed by brackets "[]" replaced with your own identifying 17*5b2ba9d3SPiotr Jasiukajtis * information: Portions Copyright [yyyy] [name of copyright owner] 18*5b2ba9d3SPiotr Jasiukajtis * 19*5b2ba9d3SPiotr Jasiukajtis * CDDL HEADER END 20*5b2ba9d3SPiotr Jasiukajtis */ 21*5b2ba9d3SPiotr Jasiukajtis/* 22*5b2ba9d3SPiotr Jasiukajtis * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 23*5b2ba9d3SPiotr Jasiukajtis */ 24*5b2ba9d3SPiotr Jasiukajtis/* 25*5b2ba9d3SPiotr Jasiukajtis * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 26*5b2ba9d3SPiotr Jasiukajtis * Use is subject to license terms. 27*5b2ba9d3SPiotr Jasiukajtis */ 28*5b2ba9d3SPiotr Jasiukajtis 29*5b2ba9d3SPiotr Jasiukajtis .file "ilogb.s" 30*5b2ba9d3SPiotr Jasiukajtis 31*5b2ba9d3SPiotr Jasiukajtis#include "libm.h" 32*5b2ba9d3SPiotr JasiukajtisLIBM_ANSI_PRAGMA_WEAK(ilogb,function) 33*5b2ba9d3SPiotr Jasiukajtis#include "xpg6.h" 34*5b2ba9d3SPiotr Jasiukajtis 35*5b2ba9d3SPiotr Jasiukajtis .data 36*5b2ba9d3SPiotr Jasiukajtis .align 8 37*5b2ba9d3SPiotr Jasiukajtistwo52: .long 0x0,0x43300000 / 2**52 38*5b2ba9d3SPiotr Jasiukajtis 39*5b2ba9d3SPiotr Jasiukajtis ENTRY(ilogb) 40*5b2ba9d3SPiotr Jasiukajtis movl 8(%esp),%eax / eax <-- hi_32(x) 41*5b2ba9d3SPiotr Jasiukajtis andl $0x7fffffff,%eax / eax <-- hi_32(abs(x)) 42*5b2ba9d3SPiotr Jasiukajtis testl $0x7ff00000,%eax / is bexp(x) 0? 43*5b2ba9d3SPiotr Jasiukajtis jz .bexp_0 / jump if x is 0 or subnormal 44*5b2ba9d3SPiotr Jasiukajtis / biased exponent is non-zero 45*5b2ba9d3SPiotr Jasiukajtis cmpl $0x7ff00000,%eax / is bexp(x) 0x7ff? 46*5b2ba9d3SPiotr Jasiukajtis jae .bexp_all_1 / jump if x is NaN or Inf 47*5b2ba9d3SPiotr Jasiukajtis shrl $20,%eax / eax <-- bexp(x) 48*5b2ba9d3SPiotr Jasiukajtis subl $1023,%eax / unbias exponent by 1023 49*5b2ba9d3SPiotr Jasiukajtis ret 50*5b2ba9d3SPiotr Jasiukajtis 51*5b2ba9d3SPiotr Jasiukajtis.bexp_all_1: 52*5b2ba9d3SPiotr Jasiukajtis movl $0x7fffffff,%eax / x is NaN or inf, so return 0x7fffffff 53*5b2ba9d3SPiotr Jasiukajtis jmp 0f 54*5b2ba9d3SPiotr Jasiukajtis 55*5b2ba9d3SPiotr Jasiukajtis.bexp_0: 56*5b2ba9d3SPiotr Jasiukajtis orl 4(%esp),%eax / test whether x is 0 57*5b2ba9d3SPiotr Jasiukajtis jnz .ilogb_subnorm 58*5b2ba9d3SPiotr Jasiukajtis movl $0x80000001,%eax / x is +/-0, so return 0x80000001 59*5b2ba9d3SPiotr Jasiukajtis0: 60*5b2ba9d3SPiotr Jasiukajtis PIC_SETUP(0) 61*5b2ba9d3SPiotr Jasiukajtis PIC_G_LOAD(movzwl,__xpg6,ecx) 62*5b2ba9d3SPiotr Jasiukajtis PIC_WRAPUP 63*5b2ba9d3SPiotr Jasiukajtis andl $_C99SUSv3_ilogb_0InfNaN_raises_invalid,%ecx 64*5b2ba9d3SPiotr Jasiukajtis cmpl $0,%ecx 65*5b2ba9d3SPiotr Jasiukajtis je 1f 66*5b2ba9d3SPiotr Jasiukajtis fldz 67*5b2ba9d3SPiotr Jasiukajtis fdivp %st,%st(0) / raise invalid as per SUSv3 68*5b2ba9d3SPiotr Jasiukajtis1: 69*5b2ba9d3SPiotr Jasiukajtis ret 70*5b2ba9d3SPiotr Jasiukajtis 71*5b2ba9d3SPiotr Jasiukajtis.ilogb_subnorm: / subnormal input 72*5b2ba9d3SPiotr Jasiukajtis fldl 4(%esp) / push x 73*5b2ba9d3SPiotr Jasiukajtis PIC_SETUP(1) 74*5b2ba9d3SPiotr Jasiukajtis fmull PIC_L(two52) / x*2**52 75*5b2ba9d3SPiotr Jasiukajtis PIC_WRAPUP 76*5b2ba9d3SPiotr Jasiukajtis subl $8,%esp / set up storage area 77*5b2ba9d3SPiotr Jasiukajtis fstpl (%esp) / store x*2**52 in storage are 78*5b2ba9d3SPiotr Jasiukajtis movl $0x7ff00000,%eax 79*5b2ba9d3SPiotr Jasiukajtis andl 4(%esp),%eax 80*5b2ba9d3SPiotr Jasiukajtis shrl $20,%eax / extract exponent of x*2**52 81*5b2ba9d3SPiotr Jasiukajtis subl $1075,%eax / unbias it by 1075 (= 1023 + 52) 82*5b2ba9d3SPiotr Jasiukajtis addl $8,%esp 83*5b2ba9d3SPiotr Jasiukajtis ret 84*5b2ba9d3SPiotr Jasiukajtis .align 4 85*5b2ba9d3SPiotr Jasiukajtis SET_SIZE(ilogb) 86