| /* strncpy - copy at most n characters from a string from source to |
| destination. For IBM S390 |
| This file is part of the GNU C Library. |
| Copyright (C) 2000, 2001, 2003 Free Software Foundation, Inc. |
| Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com). |
| |
| 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. */ |
| |
| /* |
| * R2 = address of destination (dst) |
| * R3 = address of source (src) |
| * R4 = max of bytes to copy |
| */ |
| |
| #include "sysdep.h" |
| #include "asm-syntax.h" |
| |
| ENTRY(strncpy) |
| .text |
| st %r2,24(%r15) # save dst pointer |
| slr %r2,%r3 # %r3 points to src, %r2+%r3 to dst |
| lhi %r1,3 |
| nr %r1,%r4 # last 2 bits of # bytes |
| srl %r4,2 |
| ltr %r4,%r4 # less than 4 bytes to copy ? |
| jz .L1 |
| bras %r5,.L0 # enter loop & load address of a 0 |
| .long 0 |
| .L0: icm %r0,8,0(%r3) # first byte |
| jz .L3 |
| icm %r0,4,1(%r3) # second byte |
| jz .L4 |
| icm %r0,2,2(%r3) # third byte |
| jz .L5 |
| icm %r0,1,3(%r3) # fourth byte |
| jz .L6 |
| st %r0,0(%r2,%r3) # store all four to dest. |
| la %r3,4(%r3) |
| brct %r4,.L0 |
| .L1: ltr %r1,%r1 |
| jz .Lexit |
| .L2: icm %r0,1,0(%r3) |
| stc %r0,0(%r2,%r3) |
| la %r3,1(%r3) |
| jz .L7 |
| brct %r1,.L2 |
| j .Lexit |
| .L3: icm %r0,4,0(%r5) |
| .L4: icm %r0,2,0(%r5) |
| .L5: icm %r0,1,0(%r5) |
| .L6: st %r0,0(%r2,%r3) |
| la %r3,4(%r3) |
| ahi %r4,-1 |
| j .L8 |
| .L7: ahi %r1,-1 |
| .L8: sll %r4,2 |
| alr %r4,%r1 |
| alr %r2,%r3 # start of dst area to be zeroed |
| lr %r3,%r4 |
| slr %r4,%r4 |
| slr %r5,%r5 |
| .L9: mvcle %r2,%r4,0 # pad dst with zeroes |
| jo .L9 |
| .Lexit: l %r2,24(%r15) # return dst pointer |
| br %r14 |
| END(strncpy) |
| libc_hidden_builtin_def (strncpy) |
