| /* Copyright (C) 1996-2014 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Richard Henderson (rth@tamu.edu) |
| |
| 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/>. */ |
| |
| /* Return the address of a given character within a null-terminated |
| string, or null if it is not found. |
| |
| This is generally scheduled for the EV5 (got to look out for my own |
| interests :-), but with EV4 needs in mind. There *should* be no more |
| stalls for the EV4 than there are for the EV5. |
| */ |
| |
| #include <sysdep.h> |
| |
| .set noreorder |
| .set noat |
| |
| ENTRY(strchr) |
| #ifdef PROF |
| ldgp gp, 0(pv) |
| lda AT, _mcount |
| jsr AT, (AT), _mcount |
| .prologue 1 |
| #else |
| .prologue 0 |
| #endif |
| |
| zapnot a1, 1, a1 # e0 : zero extend the search character |
| ldq_u t0, 0(a0) # .. e1 : load first quadword |
| sll a1, 8, t5 # e0 : replicate the search character |
| andnot a0, 7, v0 # .. e1 : align our loop pointer |
| or t5, a1, a1 # e0 : |
| lda t4, -1 # .. e1 : build garbage mask |
| sll a1, 16, t5 # e0 : |
| cmpbge zero, t0, t2 # .. e1 : bits set iff byte == zero |
| mskqh t4, a0, t4 # e0 : |
| or t5, a1, a1 # .. e1 : |
| sll a1, 32, t5 # e0 : |
| cmpbge zero, t4, t4 # .. e1 : bits set iff byte is garbage |
| or t5, a1, a1 # e0 : |
| xor t0, a1, t1 # .. e1 : make bytes == c zero |
| cmpbge zero, t1, t3 # e0 : bits set iff byte == c |
| or t2, t3, t0 # e1 : bits set iff char match or zero match |
| andnot t0, t4, t0 # e0 : clear garbage bits |
| bne t0, $found # .. e1 (zdb) |
| |
| $loop: ldq t0, 8(v0) # e0 : |
| addq v0, 8, v0 # .. e1 : |
| nop # e0 : |
| xor t0, a1, t1 # .. e1 (ev5 data stall) |
| cmpbge zero, t0, t2 # e0 : bits set iff byte == 0 |
| cmpbge zero, t1, t3 # .. e1 : bits set iff byte == c |
| or t2, t3, t0 # e0 : |
| beq t0, $loop # .. e1 (zdb) |
| |
| $found: negq t0, t1 # e0 : clear all but least set bit |
| and t0, t1, t0 # e1 (stall) |
| |
| and t0, t3, t1 # e0 : bit set iff byte was the char |
| beq t1, $retnull # .. e1 (zdb) |
| |
| and t0, 0xf0, t2 # e0 : binary search for that set bit |
| and t0, 0xcc, t3 # .. e1 : |
| and t0, 0xaa, t4 # e0 : |
| cmovne t2, 4, t2 # .. e1 : |
| cmovne t3, 2, t3 # e0 : |
| cmovne t4, 1, t4 # .. e1 : |
| addq t2, t3, t2 # e0 : |
| addq v0, t4, v0 # .. e1 : |
| addq v0, t2, v0 # e0 : |
| ret # .. e1 : |
| |
| $retnull: |
| mov zero, v0 # e0 : |
| ret # .. e1 : |
| |
| END(strchr) |
| |
| weak_alias (strchr, index) |
| libc_hidden_builtin_def (strchr) |
