implement SYS command.

c64/basic/cmd_sys.s

@@ -0,0 +1,32 @@
+cmd_sys:
+	
+	jsr basic_end_of_statement_check
+	bcc +
+
+	;; SYS requires an argument
+	ldx #10
+	jmp do_basic_error
+	
+*
+	jsr basic_parse_line_number
+
+	;; setup call
+	lda #$4c 		;JMP
+	sta sys_jmp
+	lda basic_line_number+0
+	sta sys_jmp+1
+	lda basic_line_number+1
+	sta sys_jmp+2
+	
+	;; Setup the register values
+	lda sys_reg_p
+	pha
+	lda sys_reg_a
+	ldx sys_reg_x
+	ldy sys_reg_y
+	plp
+
+	;; Call the routine.
+	jsr sys_jmp
+	
+	jmp basic_run_next_statement