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/*
strlwr.S
convert a string to lower case
Contributors:
Created by Reiner Patommel
THIS SOFTWARE IS NOT COPYRIGHTED
This source code is offered for use in the public domain. You may
use, modify or distribute it freely.
This code is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY. ALL WARRANTIES, EXPRESS OR IMPLIED ARE HEREBY
DISCLAIMED. This includes but is not limited to warranties of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*/
#include "macros.inc"
#define str_hi r25
#define str_lo r24
#define temp r21
; char *strlwr(char *string)
.text
.global _U(strlwr)
.type _U(strlwr), @function
_U(strlwr):
LOAD_X(str_lo, str_hi)
.strlwr_loop:
LD temp, X ; get 1st character
TST temp ; is it end of string
BREQ .strlwr_done
ORI temp, 0x20 ; make lower case
CPI temp, 'a' ; test on [a .. z]
BRLT .strlwr_next
CPI temp, 'z'+1
BRGE .strlwr_next
ST X, temp ; ok, it is a char --> store it
.strlwr_next:
ADIW XL, 1 ; point to next character
RJMP .strlwr_loop
.strlwr_done:
RET
.strlwr_end:
.size _U(strlwr), .strlwr_end - _U(strlwr)
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