| /* Copyright (C) 1996-2014 Free Software Foundation, Inc. |
| Contributed by David Mosberger (davidm@cs.arizona.edu). |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library. If not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* Finds the first bit set in an integer. Optimized for the Alpha |
| architecture. */ |
| |
| #include <sysdep.h> |
| |
| .set noreorder |
| .set noat |
| |
| |
| ENTRY(__ffs) |
| #ifdef PROF |
| ldgp gp, 0(pv) |
| lda AT, _mcount |
| jsr AT, (AT), _mcount |
| .prologue 1 |
| zap $16, 0xF0, $16 |
| br $ffsl..ng |
| #else |
| .prologue 0 |
| zap $16, 0xF0, $16 |
| # FALLTHRU |
| #endif |
| END(__ffs) |
| |
| .align 4 |
| ENTRY(ffsl) |
| #ifdef PROF |
| ldgp gp, 0(pv) |
| lda AT, _mcount |
| jsr AT, (AT), _mcount |
| .prologue 1 |
| $ffsl..ng: |
| #else |
| .prologue 0 |
| #endif |
| not $16, $1 # e0 : |
| ldi $2, -1 # .. e1 : |
| cmpbge $1, $2, $3 # e0 : bit N == 1 for byte N == 0 |
| clr $0 # .. e1 : |
| addq $3, 1, $4 # e0 : |
| bic $4, $3, $3 # e1 : bit N == 1 for first byte N != 0 |
| and $3, 0xF0, $4 # e0 : |
| and $3, 0xCC, $5 # .. e1 : |
| and $3, 0xAA, $6 # e0 : |
| cmovne $4, 4, $0 # .. e1 : |
| cmovne $5, 2, $5 # e0 : |
| cmovne $6, 1, $6 # .. e1 : |
| addl $0, $5, $0 # e0 : |
| addl $0, $6, $0 # e1 : $0 == N |
| extbl $16, $0, $1 # e0 : $1 == byte N |
| ldi $2, 1 # .. e1 : |
| negq $1, $3 # e0 : |
| and $3, $1, $3 # e1 : bit N == least bit set of byte N |
| and $3, 0xF0, $4 # e0 : |
| and $3, 0xCC, $5 # .. e1 : |
| and $3, 0xAA, $6 # e0 : |
| cmovne $4, 5, $2 # .. e1 : |
| cmovne $5, 2, $5 # e0 : |
| cmovne $6, 1, $6 # .. e1 : |
| s8addl $0, $2, $0 # e0 : mult byte ofs by 8 and sum |
| addl $5, $6, $5 # .. e1 : |
| addl $0, $5, $0 # e0 : |
| nop # .. e1 : |
| cmoveq $16, 0, $0 # e0 : trap input == 0 case. |
| ret # .. e1 : 18 |
| |
| END(ffsl) |
| |
| weak_alias (__ffs, ffs) |
| libc_hidden_def (__ffs) |
| libc_hidden_builtin_def (ffs) |
| weak_extern (ffsl) |
| weak_alias (ffsl, ffsll) |
