; Convert intext to upper case

	JMP start
intext:	DB "In Text !@#" ; Variable
	DB 0xFF	; String terminator
ucA:	DB 'A' ; upper case A value
ucZ:	DB 'Z' ; upper case Z value
lca:	DB 'a' ; lower case a value
lcz:	DB 'z' ; lower case z value
lcuc:	DB 0d ; Will hold lc to uc difference
outbuf:	DB 0xE8 ; output buffer start memloc

start:
; Calculate the difference between lca and ucA values
; Store result in lcuc
	MOV A, [ucA]
	MOV B, [lca]
	SUB B, A
	MOV [lcuc], B

; For remainder
;	reg C has the memloc of the current intext char
;	reg B has the memloc of the current output location
;	reg A has the current intext char ASCII value

	MOV C, intext ; Get 1st char of intext memloc
	MOV B, [outbuf]	; Get output buffer memloc

loopch:	MOV A, [C] ; Get next intext char value
	CMP A, 0xFF ; Check if string terminator
	JNE convch ; If not convert the character
	HLT ; halt otherwise (i.e., string terminator)

convch:	CMP A, [lca] ; Is char >= lc a?
	JB showch ; If not show the char
	CMP A, [lcz] ; Is char <= lc z?
	JA showch ; If not show the char

	SUB A, [lcuc] ; Subtract to convert to upper case

showch:	MOV [B], A ; put the char in output buffer
	INC B ; increment output buffer memloc
	INC C ; increment intext memloc
	JMP loopch ; process next character