diff options
Diffstat (limited to 'sysdeps/powerpc/powerpc32/405/strlen.S')
-rw-r--r-- | sysdeps/powerpc/powerpc32/405/strlen.S | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc32/405/strlen.S b/sysdeps/powerpc/powerpc32/405/strlen.S new file mode 100644 index 0000000000..77d22ea673 --- /dev/null +++ b/sysdeps/powerpc/powerpc32/405/strlen.S @@ -0,0 +1,75 @@ +/* Optimized strlen implementation for PowerPC476. + Copyright (C) 2010-2013 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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, see + <http://www.gnu.org/licenses/>. */ + +#include <sysdep.h> + +/* strlen + + Register Use + r3:source address and return length of string + r4:byte counter + + Implementation description + Load 2 words at a time and count bytes, if we find null we subtract one from + the count and return the count value. We need to subtract one because + we don't count the null character as a byte. */ + +EALIGN (strlen,5,0) + neg r7,r3 + clrlwi. r8,r7,29 + addi r4,0,0 + beq L(byte_count_loop) + mtctr r8 + +L(loop): + lbz r5,0(r3) + cmpi cr5,r5,0x0 + addi r3,r3,0x1 + addi r4,r4,0x1 + beq cr5,L(end_strlen) + bdnz L(loop) + +L(byte_count_loop): + lwz r5,0(r3) + lwz r6,4(r3) + dlmzb. r12,r5,r6 + add r4,r4,r12 + bne L(end_strlen) + lwz r5,8(r3) + lwz r6,12(r3) + dlmzb. r12,r5,r6 + add r4,r4,r12 + bne L(end_strlen) + lwz r5,16(r3) + lwz r6,20(r3) + dlmzb. r12,r5,r6 + add r4,r4,r12 + bne L(end_strlen) + lwz r5,24(r3) + lwz r6,28(r3) + addi r3,r3,0x20 + dlmzb. r12,r5,r6 + add r4,r4,r12 + bne L(end_strlen) + b L(byte_count_loop) + +L(end_strlen): + addi r3,r4,-1 + blr +END (strlen) +libc_hidden_builtin_def (strlen) |