145 lines
4.0 KiB
ArmAsm
145 lines
4.0 KiB
ArmAsm
/* Optimized version of the standard strcpy() function.
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This file is part of the GNU C Library.
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Copyright (C) 2000, 2001 Free Software Foundation, Inc.
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Contributed by Dan Pop <Dan.Pop@cern.ch>.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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/* Return: dest
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Inputs:
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in0: dest
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in1: src
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In this form, it assumes little endian mode. For big endian mode, the
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the two shifts in .l2 must be inverted:
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shl value = r[1], sh1 // value = w0 << sh1
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shr.u tmp = r[0], sh2 // tmp = w1 >> sh2
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*/
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#include <sysdep.h>
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#undef ret
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#define saved_lc r15
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#define saved_pr r16
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#define thresh r17
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#define dest r19
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#define src r20
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#define len r21
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#define asrc r22
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#define tmp r23
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#define pos r24
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#define w0 r25
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#define w1 r26
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#define c r27
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#define sh2 r28
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#define sh1 r29
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#define loopcnt r30
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#define value r31
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ENTRY(strcpy)
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.prologue
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alloc r2 = ar.pfs, 2, 0, 30, 32
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#define MEMLAT 2
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.rotr r[MEMLAT + 2]
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.rotp p[MEMLAT + 1]
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mov ret0 = in0 // return value = dest
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.save pr, saved_pr
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mov saved_pr = pr // save the predicate registers
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.save ar.lc, saved_lc
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mov saved_lc = ar.lc // save the loop counter
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.body
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sub tmp = r0, in0 ;; // tmp = -dest
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mov dest = in0 // dest
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mov src = in1 // src
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and loopcnt = 7, tmp ;; // loopcnt = -dest % 8
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cmp.eq p6, p0 = loopcnt, r0
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adds loopcnt = -1, loopcnt // --loopcnt
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(p6) br.cond.sptk .dest_aligned ;;
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mov ar.lc = loopcnt
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.l1: // copy -dest % 8 bytes
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ld1 c = [src], 1 // c = *src++
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;;
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st1 [dest] = c, 1 // *dest++ = c
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cmp.eq p6, p0 = c, r0
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(p6) br.cond.dpnt .restore_and_exit
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br.cloop.dptk .l1 ;;
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.dest_aligned:
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and sh1 = 7, src // sh1 = src % 8
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mov ar.lc = -1 // "infinite" loop
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and asrc = -8, src ;; // asrc = src & -OPSIZ -- align src
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sub thresh = 8, sh1
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mov pr.rot = 1 << 16 // set rotating predicates
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cmp.ne p7, p0 = r0, r0 // clear p7
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shl sh1 = sh1, 3 ;; // sh1 = 8 * (src % 8)
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sub sh2 = 64, sh1 // sh2 = 64 - sh1
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cmp.eq p6, p0 = sh1, r0 // is the src aligned?
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(p6) br.cond.sptk .src_aligned ;;
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ld8 r[1] = [asrc],8 ;;
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.align 32
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.l2:
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ld8.s r[0] = [asrc], 8
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shr.u value = r[1], sh1 ;; // value = w0 >> sh1
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czx1.r pos = value ;; // do we have an "early" zero
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cmp.lt p7, p0 = pos, thresh // in w0 >> sh1?
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(p7) br.cond.dpnt .found0
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chk.s r[0], .recovery2 // it is safe to do that only
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.back2: // after the previous test
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shl tmp = r[0], sh2 // tmp = w1 << sh2
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;;
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or value = value, tmp ;; // value |= tmp
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czx1.r pos = value ;;
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cmp.ne p7, p0 = 8, pos
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(p7) br.cond.dpnt .found0
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st8 [dest] = value, 8 // store val to dest
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br.ctop.dptk .l2 ;;
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.src_aligned:
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.l3:
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(p[0]) ld8.s r[0] = [src], 8
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(p[MEMLAT]) chk.s r[MEMLAT], .recovery3
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.back3:
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(p[MEMLAT]) mov value = r[MEMLAT]
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(p[MEMLAT]) czx1.r pos = r[MEMLAT] ;;
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(p[MEMLAT]) cmp.ne p7, p0 = 8, pos
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(p7) br.cond.dpnt .found0
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(p[MEMLAT]) st8 [dest] = r[MEMLAT], 8
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br.ctop.dptk .l3 ;;
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.found0:
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mov ar.lc = pos
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.l4:
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extr.u c = value, 0, 8 // c = value & 0xff
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shr.u value = value, 8
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;;
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st1 [dest] = c, 1
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br.cloop.dptk .l4 ;;
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.restore_and_exit:
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mov ar.lc = saved_lc // restore the loop counter
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mov pr = saved_pr, -1 // restore the predicate registers
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br.ret.sptk.many b0
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.recovery2:
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add tmp = -8, asrc ;;
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ld8 r[0] = [tmp]
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br.cond.sptk .back2
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.recovery3:
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add tmp = -(MEMLAT + 1) * 8, src ;;
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ld8 r[MEMLAT] = [tmp]
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br.cond.sptk .back3
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END(strcpy)
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