96 lines
2.7 KiB
ArmAsm
96 lines
2.7 KiB
ArmAsm
/* Optimized version of the standard strncpy() function.
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This file is part of the GNU C Library.
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Copyright (C) 2000 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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 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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in2: char count
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If n >= 24, do a memcpy(dest, src, min(strlen(src)+1, n)), followed by a
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memset(dest + strlen(src), 0, n - strlen(src) - 1) if necessary.
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Otherwise, copy characters one by one and fill with nulls if necessary. */
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#include <sysdep.h>
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#undef ret
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#define saved_pfs loc0
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#define saved_b0 loc1
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#define saved_pr loc2
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#define saved_lc loc3
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#define tmp loc4
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#define len loc5
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#define dest in0
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#define src in1
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#define n in2
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#define rc ret0
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ENTRY(strncpy)
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alloc saved_pfs = ar.pfs, 3, 6, 3, 0
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mov saved_b0 = b0
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mov saved_pr = pr
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mov saved_lc = ar.lc
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cmp.gtu p6, p0 = 24, n
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(p6) br.cond.spnt .cpyfew
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mov out0 = src
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mov tmp = gp ;;
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br.call.sptk.many b0 = strlen# ;; // rc = strlen(src);
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add len = 1, rc // include the null in len
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mov gp = tmp
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mov out0 = dest ;;
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cmp.ltu p4, p5 = len, n
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mov out1 = src ;;
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(p4) mov out2 = len
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(p5) mov out2 = n
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br.call.sptk.many b0 = memcpy# ;; // memcpy(dest, src, min(len, n));
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mov gp = tmp
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(p4) add out0 = dest, len
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(p4) mov out1 = r0
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(p4) sub out2 = n, len
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(p4) br.call.sptk.many b0 = memset# ;; // fill the rest with nulls
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(p4) mov gp = tmp
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mov rc = dest
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mov b0 = saved_b0
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mov ar.pfs = saved_pfs
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mov pr = saved_pr, -1
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br.ret.sptk.many b0
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.cpyfew:
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mov rc = dest
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cmp.eq p6, p0 = n, r0
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adds n = -1, n
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(p6) br.cond.spnt .restore_and_exit ;; // do nothing if n == 0
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mov ar.lc = n
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cmp.eq p6, p0 = r0, r0 ;; // set p6
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.loop:
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(p6) ld1 tmp = [src],1
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;;
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st1 [dest] = tmp, 1
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(p6) cmp.ne p6, p0 = tmp, r0 // clear p6 after encountering the
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br.cloop.dptk .loop ;; // null character in src
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.restore_and_exit:
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mov ar.lc = saved_lc
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mov ar.pfs = saved_pfs
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br.ret.sptk.many b0
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END(strncpy)
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