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 2005 Sun Microsystems, Inc. All rights reserved. 26 * Use is subject to license terms. 27 */ 28 29 .file "ilogbl.s" 30 31#include "libm.h" 32LIBM_ANSI_PRAGMA_WEAK(ilogbl,function) 33#include "libm_synonyms.h" 34#include "xpg6.h" 35 36 .data 37 .align 16 38two63: .4byte 0x0,0x43d00000 / 2**63 39 40 ENTRY(ilogbl) 41 movq 16(%rsp),%rax / eax <-- sign and bexp of x 42 andq $0x7fff,%rax / eax <-- bexp(x) 43 jz .bexp_0 / jump iff x is 0 or subnormal 44 / here, biased exponent is non-zero 45 testl $0x80000000,12(%rsp) / test msb of hi_32(sgnfcnd(x)) 46 jz .ilogbl_not_finite / jump if unsupported format 47 cmpq $0x7fff,%rax 48 je .ilogbl_not_finite 49 subq $16383,%rax / unbias exponent by 16383 = 0x3fff 50 ret 51 52.ilogbl_not_finite: 53 movq $0x7fffffff,%rax / x is NaN/inf/unsup 54 jmp 0f 55 56.bexp_0: 57 movq 8(%rsp),%rax / rax <-- sgnfcnd(x) 58 orq %rax,%rax 59 jnz .ilogbl_subnorm / jump iff x is subnormal 60 movq $-2147483647,%rax / x is +/-0, so return 1-2^31 610: 62 PIC_SETUP(0) 63 PIC_G_LOAD(movzwq,__xpg6,rcx) 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 701: 71 ret 72 73 74.ilogbl_subnorm: / subnormal or pseudo-denormal input 75 fldt 8(%rsp) / push x, setting D-flag 76 PIC_SETUP(1) 77 fmull PIC_L(two63) / x*2**63 78 PIC_WRAPUP 79 subq $16,%rsp 80 fstpt (%rsp) 81 movq $0x7fff,%rax 82 andq 8(%rsp),%rax / eax <-- sign and bexp of x*2**63 83 subq $16445,%rax / unbias it by (16,383 + 63) 84 addq $16,%rsp 85 ret 86 .align 16 87 SET_SIZE(ilogbl) 88