| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 1 | /* Copyright (C) 1996-2015 Free Software Foundation, Inc. |
| 2 | Contributed by David Mosberger (davidm@cs.arizona.edu). |
| 3 | This file is part of the GNU C Library. |
| 4 | |
| 5 | The GNU C Library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 2.1 of the License, or (at your option) any later version. |
| 9 | |
| 10 | The GNU C Library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with the GNU C Library. If not, see |
| 17 | <http://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | /* Finds the first bit set in an integer. Optimized for the Alpha |
| 20 | architecture. */ |
| 21 | |
| 22 | #include <sysdep.h> |
| 23 | |
| 24 | .set noreorder |
| 25 | .set noat |
| 26 | |
| 27 | |
| 28 | ENTRY(__ffs) |
| 29 | #ifdef PROF |
| 30 | ldgp gp, 0(pv) |
| 31 | lda AT, _mcount |
| 32 | jsr AT, (AT), _mcount |
| 33 | .prologue 1 |
| 34 | zap $16, 0xF0, $16 |
| 35 | br $ffsl..ng |
| 36 | #else |
| 37 | .prologue 0 |
| 38 | zap $16, 0xF0, $16 |
| 39 | # FALLTHRU |
| 40 | #endif |
| 41 | END(__ffs) |
| 42 | |
| 43 | .align 4 |
| 44 | ENTRY(ffsl) |
| 45 | #ifdef PROF |
| 46 | ldgp gp, 0(pv) |
| 47 | lda AT, _mcount |
| 48 | jsr AT, (AT), _mcount |
| 49 | .prologue 1 |
| 50 | $ffsl..ng: |
| 51 | #else |
| 52 | .prologue 0 |
| 53 | #endif |
| 54 | not $16, $1 # e0 : |
| 55 | ldi $2, -1 # .. e1 : |
| 56 | cmpbge $1, $2, $3 # e0 : bit N == 1 for byte N == 0 |
| 57 | clr $0 # .. e1 : |
| 58 | addq $3, 1, $4 # e0 : |
| 59 | bic $4, $3, $3 # e1 : bit N == 1 for first byte N != 0 |
| 60 | and $3, 0xF0, $4 # e0 : |
| 61 | and $3, 0xCC, $5 # .. e1 : |
| 62 | and $3, 0xAA, $6 # e0 : |
| 63 | cmovne $4, 4, $0 # .. e1 : |
| 64 | cmovne $5, 2, $5 # e0 : |
| 65 | cmovne $6, 1, $6 # .. e1 : |
| 66 | addl $0, $5, $0 # e0 : |
| 67 | addl $0, $6, $0 # e1 : $0 == N |
| 68 | extbl $16, $0, $1 # e0 : $1 == byte N |
| 69 | ldi $2, 1 # .. e1 : |
| 70 | negq $1, $3 # e0 : |
| 71 | and $3, $1, $3 # e1 : bit N == least bit set of byte N |
| 72 | and $3, 0xF0, $4 # e0 : |
| 73 | and $3, 0xCC, $5 # .. e1 : |
| 74 | and $3, 0xAA, $6 # e0 : |
| 75 | cmovne $4, 5, $2 # .. e1 : |
| 76 | cmovne $5, 2, $5 # e0 : |
| 77 | cmovne $6, 1, $6 # .. e1 : |
| 78 | s8addl $0, $2, $0 # e0 : mult byte ofs by 8 and sum |
| 79 | addl $5, $6, $5 # .. e1 : |
| 80 | addl $0, $5, $0 # e0 : |
| 81 | nop # .. e1 : |
| 82 | cmoveq $16, 0, $0 # e0 : trap input == 0 case. |
| 83 | ret # .. e1 : 18 |
| 84 | |
| 85 | END(ffsl) |
| 86 | |
| 87 | weak_alias (__ffs, ffs) |
| 88 | libc_hidden_def (__ffs) |
| 89 | libc_hidden_builtin_def (ffs) |
| 90 | weak_extern (ffsl) |
| 91 | weak_alias (ffsl, ffsll) |