165 lines
4.9 KiB
ArmAsm
165 lines
4.9 KiB
ArmAsm
/* Optimized version of the standard memcmp() function.
|
|
This file is part of the GNU C Library.
|
|
Copyright (C) 2000, 2001 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, write to the Free
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 USA. */
|
|
|
|
/* Return: the result of the comparison
|
|
|
|
Inputs:
|
|
in0: dest (aka s1)
|
|
in1: src (aka s2)
|
|
in2: byte count
|
|
|
|
In this form, it assumes little endian mode. For big endian mode, the
|
|
the two shifts in .l2 must be inverted:
|
|
|
|
shl tmp1[0] = r[1 + MEMLAT], sh1 // tmp1 = w0 << sh1
|
|
shr.u tmp2[0] = r[0 + MEMLAT], sh2 // tmp2 = w1 >> sh2
|
|
|
|
and all the mux1 instructions should be replaced by plain mov's. */
|
|
|
|
#include <sysdep.h>
|
|
#undef ret
|
|
|
|
#define OP_T_THRES 16
|
|
#define OPSIZ 8
|
|
#define MEMLAT 2
|
|
|
|
#define start r15
|
|
#define saved_pr r17
|
|
#define saved_lc r18
|
|
#define dest r19
|
|
#define src r20
|
|
#define len r21
|
|
#define asrc r22
|
|
#define tmp r23
|
|
#define value1 r24
|
|
#define value2 r25
|
|
#define sh2 r28
|
|
#define sh1 r29
|
|
#define loopcnt r30
|
|
|
|
ENTRY(memcmp)
|
|
.prologue
|
|
alloc r2 = ar.pfs, 3, 37, 0, 40
|
|
|
|
.rotr r[MEMLAT + 2], q[MEMLAT + 5], tmp1[4], tmp2[4], val[2]
|
|
.rotp p[MEMLAT + 4 + 1]
|
|
|
|
mov ret0 = r0 // by default return value = 0
|
|
.save pr, saved_pr
|
|
mov saved_pr = pr // save the predicate registers
|
|
.save ar.lc, saved_lc
|
|
mov saved_lc = ar.lc // save the loop counter
|
|
.body
|
|
mov dest = in0 // dest
|
|
mov src = in1 // src
|
|
mov len = in2 // len
|
|
sub tmp = r0, in0 // tmp = -dest
|
|
;;
|
|
and loopcnt = 7, tmp // loopcnt = -dest % 8
|
|
cmp.ge p6, p0 = OP_T_THRES, len // is len <= OP_T_THRES
|
|
(p6) br.cond.spnt .cmpfew // compare byte by byte
|
|
;;
|
|
cmp.eq p6, p0 = loopcnt, r0
|
|
(p6) br.cond.sptk .dest_aligned
|
|
sub len = len, loopcnt // len -= -dest % 8
|
|
adds loopcnt = -1, loopcnt // --loopcnt
|
|
;;
|
|
mov ar.lc = loopcnt
|
|
.l1: // copy -dest % 8 bytes
|
|
ld1 value1 = [src], 1 // value = *src++
|
|
ld1 value2 = [dest], 1
|
|
;;
|
|
cmp.ne p6, p0 = value1, value2
|
|
(p6) br.cond.spnt .done
|
|
br.cloop.dptk .l1
|
|
.dest_aligned:
|
|
and sh1 = 7, src // sh1 = src % 8
|
|
and tmp = -8, len // tmp = len & -OPSIZ
|
|
and asrc = -8, src // asrc = src & -OPSIZ -- align src
|
|
shr.u loopcnt = len, 3 // loopcnt = len / 8
|
|
and len = 7, len ;; // len = len % 8
|
|
shl sh1 = sh1, 3 // sh1 = 8 * (src % 8)
|
|
adds loopcnt = -1, loopcnt // --loopcnt
|
|
mov pr.rot = 1 << 16 ;; // set rotating predicates
|
|
sub sh2 = 64, sh1 // sh2 = 64 - sh1
|
|
mov ar.lc = loopcnt // set LC
|
|
cmp.eq p6, p0 = sh1, r0 // is the src aligned?
|
|
(p6) br.cond.sptk .src_aligned
|
|
add src = src, tmp // src += len & -OPSIZ
|
|
mov ar.ec = MEMLAT + 4 + 1 // four more passes needed
|
|
ld8 r[1] = [asrc], 8 ;; // r[1] = w0
|
|
.align 32
|
|
|
|
// We enter this loop with p6 cleared by the above comparison
|
|
|
|
.l2:
|
|
(p[0]) ld8 r[0] = [asrc], 8 // r[0] = w1
|
|
(p[0]) ld8 q[0] = [dest], 8
|
|
(p[MEMLAT]) shr.u tmp1[0] = r[1 + MEMLAT], sh1 // tmp1 = w0 >> sh1
|
|
(p[MEMLAT]) shl tmp2[0] = r[0 + MEMLAT], sh2 // tmp2 = w1 << sh2
|
|
(p[MEMLAT+4]) cmp.ne p6, p0 = q[MEMLAT + 4], val[1]
|
|
(p[MEMLAT+3]) or val[0] = tmp1[3], tmp2[3] // val = tmp1 | tmp2
|
|
(p6) br.cond.spnt .l2exit
|
|
br.ctop.sptk .l2
|
|
br.cond.sptk .cmpfew
|
|
.l3exit:
|
|
mux1 value1 = r[MEMLAT], @rev
|
|
mux1 value2 = q[MEMLAT], @rev
|
|
cmp.ne p6, p0 = r0, r0 ;; // clear p6
|
|
.l2exit:
|
|
(p6) mux1 value1 = val[1], @rev
|
|
(p6) mux1 value2 = q[MEMLAT + 4], @rev ;;
|
|
cmp.ltu p6, p7 = value2, value1 ;;
|
|
(p6) mov ret0 = -1
|
|
(p7) mov ret0 = 1
|
|
mov pr = saved_pr, -1 // restore the predicate registers
|
|
mov ar.lc = saved_lc // restore the loop counter
|
|
br.ret.sptk.many b0
|
|
.src_aligned:
|
|
cmp.ne p6, p0 = r0, r0 // clear p6
|
|
mov ar.ec = MEMLAT + 1 ;; // set EC
|
|
.l3:
|
|
(p[0]) ld8 r[0] = [src], 8
|
|
(p[0]) ld8 q[0] = [dest], 8
|
|
(p[MEMLAT]) cmp.ne p6, p0 = r[MEMLAT], q[MEMLAT]
|
|
(p6) br.cond.spnt .l3exit
|
|
br.ctop.dptk .l3 ;;
|
|
.cmpfew:
|
|
cmp.eq p6, p0 = len, r0 // is len == 0 ?
|
|
adds len = -1, len // --len;
|
|
(p6) br.cond.spnt .restore_and_exit ;;
|
|
mov ar.lc = len
|
|
.l4:
|
|
ld1 value1 = [src], 1
|
|
ld1 value2 = [dest], 1
|
|
;;
|
|
cmp.ne p6, p0 = value1, value2
|
|
(p6) br.cond.spnt .done
|
|
br.cloop.dptk .l4 ;;
|
|
.done:
|
|
(p6) sub ret0 = value2, value1 // don't execute it if falling thru
|
|
.restore_and_exit:
|
|
mov pr = saved_pr, -1 // restore the predicate registers
|
|
mov ar.lc = saved_lc // restore the loop counter
|
|
br.ret.sptk.many b0
|
|
END(memcmp)
|
|
|
|
weak_alias (memcmp, bcmp)
|