| /* Optimized version of the standard strchr() function. |
| This file is part of the GNU C Library. |
| Copyright (C) 2000-2016 Free Software Foundation, Inc. |
| Contributed by Dan Pop <Dan.Pop@cern.ch>. |
| |
| 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 the first occurence of chr in str or NULL |
| |
| Inputs: |
| in0: str |
| in1: chr |
| |
| A modified version of memchr.S, the search ends when the character is |
| found or the terminating null character is encountered. |
| |
| This implementation assumes little endian mode. For big endian mode, |
| the instruction czx1.r should be replaced by czx1.l. */ |
| |
| #include <sysdep.h> |
| #undef ret |
| |
| #define saved_lc r18 |
| #define poschr r19 |
| #define pos0 r20 |
| #define val1 r21 |
| #define val2 r22 |
| #define tmp r24 |
| #define chrx8 r25 |
| #define loopcnt r30 |
| |
| #define str in0 |
| #define chr in1 |
| |
| ENTRY(strchr) |
| .prologue |
| alloc r2 = ar.pfs, 2, 0, 0, 0 |
| .save ar.lc, saved_lc |
| mov saved_lc = ar.lc // save the loop counter |
| .body |
| mov ret0 = str |
| and tmp = 7, str // tmp = str % 8 |
| mux1 chrx8 = chr, @brcst |
| extr.u chr = chr, 0, 8 // retain only the last byte |
| cmp.ne p8, p0 = r0, r0 // clear p8 |
| ;; |
| sub loopcnt = 8, tmp // loopcnt = 8 - tmp |
| cmp.eq p6, p0 = tmp, r0 |
| (p6) br.cond.sptk .str_aligned;; |
| adds loopcnt = -1, loopcnt;; |
| mov ar.lc = loopcnt |
| .l1: |
| ld1 val2 = [ret0], 1 |
| ;; |
| cmp.eq p6, p0 = val2, chr |
| cmp.eq p7, p0 = val2, r0 |
| (p6) br.cond.spnt .restore_and_exit |
| (p7) br.cond.spnt .notfound |
| br.cloop.sptk .l1 |
| .str_aligned: |
| ld8 val1 = [ret0], 8;; |
| nop.b 0 |
| nop.b 0 |
| .l2: |
| ld8.s val2 = [ret0], 8 // don't bomb out here |
| czx1.r pos0 = val1 |
| xor tmp = val1, chrx8 // if val1 contains chr, tmp will |
| ;; // contain a zero in its position |
| czx1.r poschr = tmp |
| cmp.ne p6, p0 = 8, pos0 |
| ;; |
| cmp.ne p7, p0 = 8, poschr |
| (p7) br.cond.spnt .foundit |
| (p6) br.cond.spnt .notfound |
| chk.s val2, .recovery |
| .back: |
| mov val1 = val2 |
| br.cond.dptk .l2 |
| .foundit: |
| (p6) cmp.lt p8, p0 = pos0, poschr // we found chr and null in the word |
| (p8) br.cond.spnt .notfound // null was found before chr |
| add ret0 = ret0, poschr ;; |
| adds ret0 = -15, ret0 ;; // should be -16, but we decrement |
| .restore_and_exit: // ret0 in the next instruction |
| adds ret0 = -1, ret0 // ret0 was pointing 1 char too far |
| mov ar.lc = saved_lc // restore the loop counter |
| br.ret.sptk.many b0 |
| .notfound: |
| mov ret0 = r0 // return NULL if null was found |
| mov ar.lc = saved_lc |
| br.ret.sptk.many b0 |
| .recovery: |
| adds ret0 = -8, ret0;; |
| ld8 val2 = [ret0], 8 // bomb out here |
| br.cond.sptk .back |
| END(strchr) |
| |
| weak_alias (strchr, index) |
| libc_hidden_builtin_def (strchr) |