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 "roundl.s" 30 31#include "libm.h" 32LIBM_ANSI_PRAGMA_WEAK(roundl,function) 33#include "libm_synonyms.h" 34#undef fabs 35 36 .section .rodata 37 .align 4 38.Lhalf: .float 0.5 39 40 ENTRY(roundl) 41 movl %esp,%ecx 42 subl $8,%esp 43 fstcw -8(%ecx) 44 fldt 4(%ecx) 45 movw -8(%ecx),%dx 46 andw $0xf3ff,%dx 47 movw %dx,-4(%ecx) 48 fldcw -4(%ecx) / set RD = to_nearest 49 fld %st(0) 50 frndint / [x],x 51 fstcw -4(%ecx) 52 movw -4(%ecx),%dx 53 andw $0xf3ff,%dx 54 movw -8(%ecx),%ax 55 andw $0x0c00,%ax 56 orw %dx,%ax 57 movw %ax,-8(%ecx) 58 fldcw -8(%ecx) / restore RD 59 fucom / check if x is already an integer 60 fstsw %ax 61 sahf 62 jp 0f 63 je 0f 64 fxch / x,[x] 65 fsub %st(1),%st / x-[x],[x] 66 fabs / |x-[x]|,[x] 67 PIC_SETUP(1) 68 fcoms PIC_L(.Lhalf) 69 PIC_WRAPUP 70 fnstsw %ax 71 sahf 72 jae 2f / if |x-[x]| = 0.5 goto halfway, 73 / most cases will not take branch. 740: 75 addl $8,%esp 76 fstp %st(0) 77 ret 782: 79 / x = n+0.5, recompute roundl(x) as x+sign(x)*0.5 80 fldt 4(%ecx) / x, 0.5, [x] 81 movw 12(%ecx),%ax / sign+exp of x 82 andw $0x8000,%ax / look at sign bit 83 jnz 3f 84 faddp 85 addl $8,%esp 86 fstp %st(1) 87 ret 883: 89 / here, x is negative, so return x-0.5 90 fsubp %st,%st(1) / x-0.5,[x] 91 addl $8,%esp 92 fstp %st(1) 93 ret 94 .align 4 95 SET_SIZE(roundl) 96