implement RUN command. Show line number in errors when in program mode.

c64/basic/cmd_run.s

@@ -0,0 +1,11 @@
+cmd_run:
+	;; XXX - Parse starting line number
+
+	;; Reset line pointer to first line of program.
+	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
+
+	;; Run it!
+	jmp basic_execute_from_current_line

c64/basic/cmd_unimplemented.s

@@ -10,7 +10,6 @@ cmd_dim:
 cmd_read:
 cmd_let:
 cmd_goto:
-cmd_run:
 cmd_if:
 cmd_restore:
 cmd_gosub:

c64/basic/do_basic_error.s

@@ -22,6 +22,18 @@ do_basic_error:
 	ldx #33
 	jsr print_packed_message
 
+	lda basic_current_line_number+1
+	cmp #$ff
+	beq +
+
+	;; We were in a program, so show IN <line>
+	jsr printf
+	.byte " IN ",0
+
+	lda basic_current_line_number+1
+	ldx basic_current_line_number+0
+	jsr print_integer
+*
 	;; New lines
 	lda #$0d
 	jsr $ffd2