diff options
Diffstat (limited to 'lib/libc/ia64/string/ffs.S')
| -rw-r--r-- | lib/libc/ia64/string/ffs.S | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/lib/libc/ia64/string/ffs.S b/lib/libc/ia64/string/ffs.S new file mode 100644 index 0000000..9c6e56e --- /dev/null +++ b/lib/libc/ia64/string/ffs.S @@ -0,0 +1,99 @@ +/* $FreeBSD$ */ +/* $NetBSD: ffs.S,v 1.3 1996/10/17 03:08:13 cgd Exp $ */ + +/* + * Copyright (c) 1995 Christopher G. Demetriou + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by Christopher G. Demetriou + * for the NetBSD Project. + * 4. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <machine/asm.h> + +ENTRY(ffs, 1) + sxt4 r14=in0 ;; + cmp.eq p6,p0=r14,r0 +(p6) br.dpnt.few Lallzero + + /* + * Initialize return value (ret0), and set up r15 so that it + * contains the mask with only the lowest bit set. + */ + sub r15=r0,r14 + mov ret0=1 ;; + and r15=r14,r15 + + extr.u r16=r15,0,8 ;; + cmp.ne p6,p0=r0,r16 +(p6) br.dptk.few Ldo8 + + /* + * If lower 16 bits empty, add 16 to result and use upper 16. + */ + extr.u r16=r15,0,16 ;; + cmp.ne p6,p0=r0,r16 +(p6) br.dptk.few Ldo16 + extr.u r15=r15,16,16 + add ret0=16,ret0 + +Ldo16: + /* + * If lower 8 bits empty, add 8 to result and use upper 8. + */ + extr.u r16=r15,0,8 ;; + cmp.ne p6,p0=r0,r16 +(p6) br.dptk.few Ldo8 + extr.u r15=r15,8,24 + add ret0=8,ret0 + +Ldo8: + and r16=0x0f,r15 /* lower 4 of 8 empty? */ + and r17=0x33,r15 /* lower 2 of each 4 empty? */ + and r18=0x55,r15 ;; /* lower 1 of each 2 empty? */ + cmp.ne p6,p0=r16,r0 + cmp.ne p7,p0=r17,r0 + cmp.ne p8,p0=r18,r0 + + /* If lower 4 bits empty, add 4 to result. */ +(p6) br.dptk.few Ldo4 + add ret0=4,ret0 + +Ldo4: /* If lower 2 bits of each 4 empty, add 2 to result. */ +(p7) br.dptk.few Ldo2 + add ret0=2,ret0 + +Ldo2: /* If lower bit of each 2 empty, add 1 to result. */ +(p8) br.dptk.few Ldone + add ret0=1,ret0 + +Ldone: + br.ret.sptk.few rp + +Lallzero: + mov ret0=0 + br.ret.sptk.few rp +END(ffs) |
