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 "xpg6.h" 34 35 .data 36 .align 16 37two63: .4byte 0x0,0x43d00000 / 2**63 38 39 ENTRY(ilogbl) 40 movq 16(%rsp),%rax / eax <-- sign and bexp of x 41 andq $0x7fff,%rax / eax <-- bexp(x) 42 jz .bexp_0 / jump iff x is 0 or subnormal 43 / here, biased exponent is non-zero 44 testl $0x80000000,12(%rsp) / test msb of hi_32(sgnfcnd(x)) 45 jz .ilogbl_not_finite / jump if unsupported format 46 cmpq $0x7fff,%rax 47 je .ilogbl_not_finite 48 subq $16383,%rax / unbias exponent by 16383 = 0x3fff 49 ret 50 51.ilogbl_not_finite: 52 movq $0x7fffffff,%rax / x is NaN/inf/unsup 53 jmp 0f 54 55.bexp_0: 56 movq 8(%rsp),%rax / rax <-- sgnfcnd(x) 57 orq %rax,%rax 58 jnz .ilogbl_subnorm / jump iff x is subnormal 59 movq $-2147483647,%rax / x is +/-0, so return 1-2^31 600: 61 PIC_SETUP(0) 62 PIC_G_LOAD(movzwq,__xpg6,rcx) 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 73.ilogbl_subnorm: / subnormal or pseudo-denormal input 74 fldt 8(%rsp) / push x, setting D-flag 75 PIC_SETUP(1) 76 fmull PIC_L(two63) / x*2**63 77 PIC_WRAPUP 78 subq $16,%rsp 79 fstpt (%rsp) 80 movq $0x7fff,%rax 81 andq 8(%rsp),%rax / eax <-- sign and bexp of x*2**63 82 subq $16445,%rax / unbias it by (16,383 + 63) 83 addq $16,%rsp 84 ret 85 .align 16 86 SET_SIZE(ilogbl) 87