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48 lines
839 B
ArmAsm

;
; Ullrich von Bassewitz, 02.06.1998
;
; char* strupper (char* s);
; char* strupr (char* s);
;
; Non-ANSI
;
.export _strupper, _strupr
.import popax
.import __ctype
.importzp ptr1, ptr2
.include "ctype.inc"
_strupper:
_strupr:
sta ptr1 ; Save s (working copy)
stx ptr1+1
sta ptr2
sta ptr2+2 ; save function result
ldy #0
loop: lda (ptr1),y ; get character
beq L9 ; jump if done
tax
lda __ctype,x ; get character classification
and #CT_LOWER ; lower case char?
beq L1 ; jump if no
txa ; get character back into accu
clc
adc #<('A'-'a') ; make upper case char
sta (ptr1),y ; store back
L1: iny ; next char
bne loop
inc ptr1+1 ; handle offset overflow
bne loop ; branch always
; Done, return the argument string
L9: lda ptr2
ldx ptr2+1
rts