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Diffstat (limited to 'sysdeps/ia64/memchr.S')
| -rw-r--r-- | sysdeps/ia64/memchr.S | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/sysdeps/ia64/memchr.S b/sysdeps/ia64/memchr.S new file mode 100644 index 0000000..602dbf9 --- /dev/null +++ b/sysdeps/ia64/memchr.S @@ -0,0 +1,157 @@ +/* Optimized version of the standard memchr() function. + This file is part of the GNU C Library. + Copyright (C) 2000-2014 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 + 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_pr r15 +#define saved_lc r16 +#define chr r17 +#define len r18 +#define last r20 +#define val r21 +#define tmp r24 +#define chrx8 r25 +#define loopcnt r30 + +#define str in0 + +ENTRY(__memchr) + .prologue + alloc r2 = ar.pfs, 3, 0, 29, 32 +#include "softpipe.h" + .rotr value[MEMLAT+1], addr[MEMLAT+3], aux[2], poschr[2] + .rotp p[MEMLAT+3] + .save ar.lc, saved_lc + mov saved_lc = ar.lc // save the loop counter + .save pr, saved_pr + mov saved_pr = pr // save the predicates + .body + mov ret0 = str + add last = str, in2 // last byte + 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.s value[0] = [ret0], 8 // speculative load +(p[MEMLAT]) chk.s value[MEMLAT], .recovery // check and recovery +(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: + .pred.rel "mutex" p6, p7 +(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.lc = saved_lc + br.ret.sptk.many b0 + +.recovery: +#if MEMLAT != 6 +# error "MEMLAT must be 6!" +#endif +(p[MEMLAT-6]) add ret0 = -8, ret0;; +(p[MEMLAT-5]) add ret0 = -8, ret0;; +(p[MEMLAT-4]) add ret0 = -8, ret0;; +(p[MEMLAT-3]) add ret0 = -8, ret0;; +(p[MEMLAT-2]) add ret0 = -8, ret0;; +(p[MEMLAT-1]) add ret0 = -8, ret0;; +(p[MEMLAT]) add ret0 = -8, ret0;; +(p[MEMLAT+1]) add ret0 = -8, ret0;; +(p[MEMLAT+2]) add ret0 = -8, ret0;; +.l4: + mov addr[MEMLAT+2] = ret0 + ld8 tmp = [ret0];; // load the first unchecked 8byte + xor aux[1] = tmp, chrx8;; + czx1.r poschr[1] = aux[1];; + cmp.ne p7, p0 = 8, poschr[1];; +(p7) add ret0 = addr[MEMLAT+2], poschr[1];; +(p7) cmp.geu p6, p7 = ret0, last // don't go over the last byte +(p6) br.cond.spnt .notfound;; +(p7) br.cond.spnt .foundit;; + adds ret0 = 8, ret0 // load the next unchecked 8byte + br.sptk .l4;; + +END(__memchr) + +weak_alias (__memchr, memchr) +libc_hidden_builtin_def (memchr) |