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+/* Optimized version of the standard memchr() function.
+ This file is part of the GNU C Library.
+ Copyright (C) 2000 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 Library General Public License as
+ published by the Free Software Foundation; either version 2 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
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+/* Return: the address of the first occurence of chr in str or NULL
+
+ Inputs:
+ in0: str
+ in1: chr
+ in2: byte count
+
+ This implementation assumes little endian mode. For big endian mode,
+ the instruction czx1.r should be replaced by czx1.l.
+
+ The algorithm is fairly straightforward: search byte by byte until we
+ we get to a word aligned address, then search word by word as much as
+ possible; the remaining few bytes are searched one at a time.
+
+ The word by word search is performed by xor-ing the word with a word
+ containing chr in every byte. If there is a hit, the result will
+ contain a zero byte in the corresponding position. The presence and
+ position of that zero byte is detected with a czx instruction.
+
+ All the loops in this function could have had the internal branch removed
+ if br.ctop and br.cloop could be predicated :-(. */
+
+#include <sysdep.h>
+#undef ret
+
+#define saved_pfs r14
+#define saved_pr r15
+#define saved_lc r16
+#define chr r17
+#define len r18
+#define pos0 r20
+#define val r21
+#define tmp r24
+#define chrx8 r25
+#define loopcnt r30
+
+#define str in0
+
+ENTRY(memchr)
+ alloc saved_pfs = ar.pfs, 3, 0, 29, 32
+#include "softpipe.h"
+ .rotr value[MEMLAT+1], addr[MEMLAT+3], aux[2], poschr[2]
+ .rotp p[MEMLAT+3]
+ mov saved_lc = ar.lc // save the loop counter
+ mov saved_pr = pr // save the predicates
+ mov ret0 = str
+ and tmp = 7, str // tmp = str % 8
+ cmp.ne p7, p0 = r0, r0 // clear p7
+ extr.u chr = in1, 0, 8 // chr = (unsigned char) in1
+ mov len = in2
+ cmp.gtu p6, p0 = 16, in2 // use a simple loop for short
+(p6) br.cond.spnt .srchfew ;; // searches
+ sub loopcnt = 8, tmp // loopcnt = 8 - tmp
+ cmp.eq p6, p0 = tmp, r0
+(p6) br.cond.sptk .str_aligned;;
+ sub len = len, loopcnt
+ adds loopcnt = -1, loopcnt;;
+ mov ar.lc = loopcnt
+.l1:
+ ld1 val = [ret0], 1
+ ;;
+ cmp.eq p6, p0 = val, chr
+(p6) br.cond.spnt .foundit
+ br.cloop.sptk .l1 ;;
+.str_aligned:
+ cmp.ne p6, p0 = r0, r0 // clear p6
+ shr.u loopcnt = len, 3 // loopcnt = len / 8
+ and len = 7, len ;; // remaining len = len & 7
+ adds loopcnt = -1, loopcnt
+ mov ar.ec = MEMLAT + 3
+ mux1 chrx8 = chr, @brcst ;; // get a word full of chr
+ mov ar.lc = loopcnt
+ mov pr.rot = 1 << 16 ;;
+.l2:
+(p[0]) mov addr[0] = ret0
+(p[0]) ld8 value[0] = [ret0], 8
+(p[MEMLAT]) xor aux[0] = value[MEMLAT], chrx8
+(p[MEMLAT+1]) czx1.r poschr[0] = aux[1]
+(p[MEMLAT+2]) cmp.ne p7, p0 = 8, poschr[1]
+(p7) br.cond.dpnt .foundit
+ br.ctop.dptk .l2
+.srchfew:
+ adds loopcnt = -1, len
+ cmp.eq p6, p0 = len, r0
+(p6) br.cond.spnt .notfound ;;
+ mov ar.lc = loopcnt
+.l3:
+ ld1 val = [ret0], 1
+ ;;
+ cmp.eq p6, p0 = val, chr
+(p6) br.cond.dpnt .foundit
+ br.cloop.sptk .l3 ;;
+.notfound:
+ cmp.ne p6, p0 = r0, r0 // clear p6 (p7 was already 0 when we got here)
+ mov ret0 = r0 ;; // return NULL
+.foundit:
+(p6) adds ret0 = -1, ret0 // if we got here from l1 or l3
+(p7) add ret0 = addr[MEMLAT+2], poschr[1] // if we got here from l2
+ mov pr = saved_pr, -1
+ mov ar.pfs = saved_pfs
+ mov ar.lc = saved_lc
+ br.ret.sptk.many b0
+
+END(memchr)