begin implementing LIST command

c64/basic/cmd_list.s

@@ -0,0 +1,38 @@
+	;; LIST basic text.
+	;; XXX - Doesn't currently support line number ranges
+
+cmd_list:
+
+	;; Set current line pointer to start of memory
+	lda basic_start_of_text_ptr+0
+	sta basic_current_line_ptr+0
+	lda basic_start_of_text_ptr+1
+	sta basic_current_line_ptr+1
+
+list_loop:
+	ldx #<basic_current_line_ptr
+	ldy #0
+	jsr peek_pointer_null_check
+	bcs list_more_lines
+
+	jmp basic_main_loop
+
+list_more_lines:
+	;; Print line number
+	ldy #3
+	jsr peek_under_roms
+	pha
+	dey
+	jsr peek_under_roms
+	tax
+	pla
+	jsr print_integer
+
+	;; Print end of line
+	lda #$0d
+	jsr $ffd2
+
+	;; Now link to the next line
+	jsr basic_find_next_line
+	jmp list_loop
+