;
.export _tolower
- .import __ctype, __cdiff
+ .import __ctype
_tolower:
cpx #$00 ; Outside valid range?
lsr a ; Get bit 1 (upper case char) into carry
tya ; Get char back into A
bcc L9 ; Jump if no upper case char
- sbc __cdiff ; Make lower case char (carry already set)
+ sbc #<('A'-'a') ; Make lower case char (carry already set)
L9: rts