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/* Optimized version of the standard strncpy() 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 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: dest
Inputs:
in0: dest
in1: src
in2: char count
If n >= 24, do a memcpy(dest, src, min(strlen(src)+1, n)), followed by a
memset(dest + strlen(src), 0, n - strlen(src) - 1) if necessary.
Otherwise, copy characters one by one and fill with nulls if necessary. */
#include <sysdep.h>
#undef ret
#define saved_b0 loc0
#define saved_pfs loc1
#define saved_pr loc2
#define saved_lc loc3
#define tmp loc4
#define len loc5
#define dest in0
#define src in1
#define n in2
#define rc ret0
ENTRY(strncpy)
.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(3)
alloc saved_pfs = ar.pfs, 3, 6, 3, 0
mov saved_b0 = b0
.save pr, saved_pr
mov saved_pr = pr
.save ar.lc, saved_lc
mov saved_lc = ar.lc
.body
cmp.gtu p6, p0 = 24, n
(p6) br.cond.spnt .cpyfew
mov out0 = src
mov tmp = gp ;;
br.call.sptk.many b0 = strlen# ;; // rc = strlen(src);
add len = 1, rc // include the null in len
mov gp = tmp
mov out0 = dest ;;
cmp.ltu p4, p5 = len, n
mov out1 = src ;;
(p4) mov out2 = len
(p5) mov out2 = n
br.call.sptk.many b0 = memcpy# ;; // memcpy(dest, src, min(len, n));
mov gp = tmp
(p4) add out0 = dest, len
(p4) mov out1 = r0
(p4) sub out2 = n, len
(p4) br.call.sptk.many b0 = memset# ;; // fill the rest with nulls
(p4) mov gp = tmp
mov rc = dest
mov b0 = saved_b0
mov ar.pfs = saved_pfs
mov pr = saved_pr, -1
br.ret.sptk.many b0
.cpyfew:
mov rc = dest
cmp.eq p6, p0 = n, r0
adds n = -1, n
(p6) br.cond.spnt .restore_and_exit ;; // do nothing if n == 0
mov ar.lc = n
cmp.eq p6, p0 = r0, r0 ;; // set p6
.loop:
(p6) ld1 tmp = [src],1
;;
st1 [dest] = tmp, 1
(p6) cmp.ne p6, p0 = tmp, r0 // clear p6 after encountering the
br.cloop.dptk .loop ;; // null character in src
.restore_and_exit:
mov ar.lc = saved_lc
mov ar.pfs = saved_pfs
br.ret.sptk.many b0
END(strncpy)
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