ffs.S revision 1.1.2.2
1 1.1.2.2 pgoyette /* $NetBSD: ffs.S,v 1.1.2.2 2016/08/06 00:18:38 pgoyette Exp $ */ 2 1.1.2.2 pgoyette 3 1.1.2.2 pgoyette /* 4 1.1.2.2 pgoyette * Copyright (c) 1995 Christopher G. Demetriou 5 1.1.2.2 pgoyette * All rights reserved. 6 1.1.2.2 pgoyette * 7 1.1.2.2 pgoyette * Redistribution and use in source and binary forms, with or without 8 1.1.2.2 pgoyette * modification, are permitted provided that the following conditions 9 1.1.2.2 pgoyette * are met: 10 1.1.2.2 pgoyette * 1. Redistributions of source code must retain the above copyright 11 1.1.2.2 pgoyette * notice, this list of conditions and the following disclaimer. 12 1.1.2.2 pgoyette * 2. Redistributions in binary form must reproduce the above copyright 13 1.1.2.2 pgoyette * notice, this list of conditions and the following disclaimer in the 14 1.1.2.2 pgoyette * documentation and/or other materials provided with the distribution. 15 1.1.2.2 pgoyette * 3. All advertising materials mentioning features or use of this software 16 1.1.2.2 pgoyette * must display the following acknowledgement: 17 1.1.2.2 pgoyette * This product includes software developed by Christopher G. Demetriou 18 1.1.2.2 pgoyette * for the NetBSD Project. 19 1.1.2.2 pgoyette * 4. The name of the author may not be used to endorse or promote products 20 1.1.2.2 pgoyette * derived from this software without specific prior written permission 21 1.1.2.2 pgoyette * 22 1.1.2.2 pgoyette * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 1.1.2.2 pgoyette * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 1.1.2.2 pgoyette * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 1.1.2.2 pgoyette * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 1.1.2.2 pgoyette * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 1.1.2.2 pgoyette * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 1.1.2.2 pgoyette * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 1.1.2.2 pgoyette * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 1.1.2.2 pgoyette * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 1.1.2.2 pgoyette * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 1.1.2.2 pgoyette * 33 1.1.2.2 pgoyette * __FBSDID("$FreeBSD: releng/10.1/lib/libc/ia64/string/ffs.S 111777 2003-03-03 01:09:46Z obrien $"); 34 1.1.2.2 pgoyette * 35 1.1.2.2 pgoyette */ 36 1.1.2.2 pgoyette 37 1.1.2.2 pgoyette #include <machine/asm.h> 38 1.1.2.2 pgoyette /* 39 1.1.2.2 pgoyette 40 1.1.2.2 pgoyette /* 41 1.1.2.2 pgoyette * int 42 1.1.2.2 pgoyette * ffs(int value); 43 1.1.2.2 pgoyette */ 44 1.1.2.2 pgoyette ENTRY(ffs, 1) 45 1.1.2.2 pgoyette sxt4 r14=in0 ;; 46 1.1.2.2 pgoyette cmp.eq p6,p0=r14,r0 47 1.1.2.2 pgoyette (p6) br.dpnt.few Lallzero 48 1.1.2.2 pgoyette 49 1.1.2.2 pgoyette /* 50 1.1.2.2 pgoyette * Initialize return value (ret0), and set up r15 so that it 51 1.1.2.2 pgoyette * contains the mask with only the lowest bit set. 52 1.1.2.2 pgoyette */ 53 1.1.2.2 pgoyette sub r15=r0,r14 54 1.1.2.2 pgoyette mov ret0=1 ;; 55 1.1.2.2 pgoyette and r15=r14,r15 ;; 56 1.1.2.2 pgoyette 57 1.1.2.2 pgoyette extr.u r16=r15,0,8 ;; 58 1.1.2.2 pgoyette cmp.ne p6,p0=r0,r16 59 1.1.2.2 pgoyette (p6) br.dptk.few Ldo8 60 1.1.2.2 pgoyette 61 1.1.2.2 pgoyette /* 62 1.1.2.2 pgoyette * If lower 16 bits empty, add 16 to result and use upper 16. 63 1.1.2.2 pgoyette */ 64 1.1.2.2 pgoyette extr.u r16=r15,0,16 ;; 65 1.1.2.2 pgoyette cmp.ne p6,p0=r0,r16 66 1.1.2.2 pgoyette (p6) br.dptk.few Ldo16 67 1.1.2.2 pgoyette extr.u r15=r15,16,16 68 1.1.2.2 pgoyette add ret0=16,ret0 ;; 69 1.1.2.2 pgoyette 70 1.1.2.2 pgoyette Ldo16: 71 1.1.2.2 pgoyette /* 72 1.1.2.2 pgoyette * If lower 8 bits empty, add 8 to result and use upper 8. 73 1.1.2.2 pgoyette */ 74 1.1.2.2 pgoyette extr.u r16=r15,0,8 ;; 75 1.1.2.2 pgoyette cmp.ne p6,p0=r0,r16 76 1.1.2.2 pgoyette (p6) br.dptk.few Ldo8 77 1.1.2.2 pgoyette extr.u r15=r15,8,24 78 1.1.2.2 pgoyette add ret0=8,ret0 ;; 79 1.1.2.2 pgoyette 80 1.1.2.2 pgoyette Ldo8: 81 1.1.2.2 pgoyette and r16=0x0f,r15 /* lower 4 of 8 empty? */ 82 1.1.2.2 pgoyette and r17=0x33,r15 /* lower 2 of each 4 empty? */ 83 1.1.2.2 pgoyette and r18=0x55,r15 ;; /* lower 1 of each 2 empty? */ 84 1.1.2.2 pgoyette cmp.ne p6,p0=r16,r0 85 1.1.2.2 pgoyette cmp.ne p7,p0=r17,r0 86 1.1.2.2 pgoyette cmp.ne p8,p0=r18,r0 87 1.1.2.2 pgoyette 88 1.1.2.2 pgoyette /* If lower 4 bits empty, add 4 to result. */ 89 1.1.2.2 pgoyette (p6) br.dptk.few Ldo4 90 1.1.2.2 pgoyette add ret0=4,ret0 ;; 91 1.1.2.2 pgoyette 92 1.1.2.2 pgoyette Ldo4: /* If lower 2 bits of each 4 empty, add 2 to result. */ 93 1.1.2.2 pgoyette (p7) br.dptk.few Ldo2 94 1.1.2.2 pgoyette add ret0=2,ret0 ;; 95 1.1.2.2 pgoyette 96 1.1.2.2 pgoyette Ldo2: /* If lower bit of each 2 empty, add 1 to result. */ 97 1.1.2.2 pgoyette (p8) br.dptk.few Ldone 98 1.1.2.2 pgoyette add ret0=1,ret0 99 1.1.2.2 pgoyette 100 1.1.2.2 pgoyette Ldone: 101 1.1.2.2 pgoyette br.ret.sptk.few rp 102 1.1.2.2 pgoyette 103 1.1.2.2 pgoyette Lallzero: 104 1.1.2.2 pgoyette mov ret0=0 105 1.1.2.2 pgoyette br.ret.sptk.few rp 106 1.1.2.2 pgoyette END(ffs) 107
Indexes created Thu Oct 23 22:10:10 GMT 2025