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 "ilogbl.s" 30 31 #include "libm.h" 32 LIBM_ANSI_PRAGMA_WEAK(ilogbl,function) 33 #include "libm_synonyms.h" 34 #include "xpg6.h" 35 36 .data 37 .align 8 38 two63: .long 0x0,0x43d00000 / 2**63 39 40 ENTRY(ilogbl) 41 movl 12(%esp),%eax / eax <-- sign and bexp of x 42 andl $0x00007fff,%eax / eax <-- bexp(x) 43 jz .bexp_0 / jump iff x is 0 or subnormal 44 / here, biased exponent is non-zero 45 testl $0x80000000,8(%esp) / test msb of hi_32(sgnfcnd(x)) 46 jz .ilogbl_not_finite / jump if unsupported format 47 cmpl $0x00007fff,%eax 48 je .ilogbl_not_finite 49 subl $16383,%eax / unbias exponent by 16383 = 0x3fff 50 ret 51 52 .ilogbl_not_finite: 53 movl $0x7fffffff,%eax / x is NaN/inf/unsup 54 jmp 0f 55 56 .bexp_0: 57 movl 8(%esp),%eax / eax <-- hi_32(sgnfcnd(x)) 58 orl 4(%esp),%eax / test whether x is 0 59 jnz .ilogbl_subnorm / jump iff x is subnormal 60 movl $0x80000001,%eax / x is +/-0, so return 0x80000001 61 0: 62 PIC_SETUP(0) 63 PIC_G_LOAD(movzwl,__xpg6,ecx) 64 PIC_WRAPUP 65 andl $_C99SUSv3_ilogb_0InfNaN_raises_invalid,%ecx 66 cmpl $0,%ecx 67 je 1f 68 fldz 69 fdivp %st,%st(0) / raise invalid as per SUSv3 70 1: 71 ret 72 73 74 .ilogbl_subnorm: / subnormal or pseudo-denormal input 75 fldt 4(%esp) / push x, setting D-flag 76 PIC_SETUP(1) 77 fmull PIC_L(two63) / x*2**63 78 PIC_WRAPUP 79 subl $12,%esp 80 fstpt (%esp) 81 movl $0x00007fff,%eax 82 andl 8(%esp),%eax / eax <-- sign and bexp of x*2**63 83 subl $16445,%eax / unbias it by (16,383 + 63) 84 addl $12,%esp 85 ret 86 .align 4 87 SET_SIZE(ilogbl)