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 "round.s" 30 31#include "libm.h" 32LIBM_ANSI_PRAGMA_WEAK(round,function) 33 34 .section .rodata 35 .align 4 36.Lhalf: .float 0.5 37 38 ENTRY(round) 39 movl %esp,%ecx 40 subl $8,%esp 41 fstcw -8(%ecx) 42 fldl 4(%ecx) 43 movw -8(%ecx),%dx 44 andw $0xf3ff,%dx 45 movw %dx,-4(%ecx) 46 fldcw -4(%ecx) / set RD = to_nearest 47 fld %st(0) 48 frndint / [x],x 49 fstcw -4(%ecx) 50 movw -4(%ecx),%dx 51 andw $0xf3ff,%dx 52 movw -8(%ecx),%ax 53 andw $0x0c00,%ax 54 orw %dx,%ax 55 movw %ax,-8(%ecx) 56 fldcw -8(%ecx) / restore RD 57 fucom / check if x is already an integer 58 fstsw %ax 59 sahf 60 jp 0f 61 je 0f 62 fxch / x,[x] 63 fsub %st(1),%st / x-[x],[x] 64 fabs / |x-[x]|,[x] 65 PIC_SETUP(1) 66 fcoms PIC_L(.Lhalf) 67 PIC_WRAPUP 68 fnstsw %ax 69 sahf 70 jae 2f / if |x-[x]| = 0.5 goto halfway, 71 / most cases will not take branch. 720: 73 addl $8,%esp 74 fstp %st(0) 75 ret 762: 77 / x = n+0.5, recompute round(x) as x+sign(x)*0.5 78 fldl 4(%ecx) / x, 0.5, [x] 79 movl 8(%ecx),%eax / high part of x 80 andl $0x80000000,%eax 81 jnz 3f 82 faddp 83 addl $8,%esp 84 fstp %st(1) 85 ret 863: 87 / here, x is negative, so return x-0.5 88 fsubp %st,%st(1) / x-0.5,[x] 89 addl $8,%esp 90 fstp %st(1) 91 ret 92 .align 4 93 SET_SIZE(round) 94