jimmy id's amazing program, new and improved

jimmy/Makefile

@@ -0,0 +1,11 @@
+TARGET = jimmy
+
+ASM  := xa
+FLAG := -O PETSCREEN
+SRC  := jimmy.S
+
+${TARGET}.prg: ${SRC}
+	${ASM} $< ${FLAG} -o $@
+
+clean:
+	rm -f ${TARGET}.prg

jimmy/jimmy.S

@@ -0,0 +1,40 @@
+.byte $01, $08		; Load this .prg into $0801
+
+*=$0801
+.byte $0c, $08, $0a, $00, $9e, $20
+.byte $34, $30, $39, $36, $00, $00
+.byte $00
+
+.dsb $1000 - *		; Pad with zeroes from PC to $1000
+
+
+	ldx #$08		; Screen colours
+	stx $d020
+	ldx #$00
+	stx $d021
+
+	jsr $e544		; clear screen
+	jsr print_string
+
+loop:
+	lda $dc01		; Scans the keyboard buffer
+	cmp #$ef		; If user presses Space ($ef) then quit
+	bne loop
+
+	rts
+
+print_string:
+	ldx #$00
+print_loop:
+	lda message,x
+
+	cmp #$0			; return on null terminator
+	bne print_continue
+	rts
+
+print_continue:
+	sta $0428,x
+	inx
+	jmp print_loop
+
+message: .asc "welcome to scat os@"