more cleanup in BASIC

src/basic/basic_commands_CC/cmd_old.s

@@ -11,53 +11,14 @@ cmd_old:
 	inx
 	bne_16 do_DIRECT_MODE_ONLY_error
 
-	// Now try to restore program linkage
+	// Now try to restore program linkage and VARTAB
 
 	ldy #$01
 	tya
 	sta (TXTTAB),y
 
 	jsr LINKPRG
-
-	// Now we have to restore VARTAB    XXX deduplicate this with line editor
-
-	lda TXTTAB+0
-	sta OLDTXT+0
-	lda TXTTAB+1
-	sta OLDTXT+1
-!:
-	lda OLDTXT+0
-	sta VARTAB+0
-	lda OLDTXT+1
-	sta VARTAB+1
-
-	jsr basic_follow_link_to_next_line
-
-	lda OLDTXT+0
-	ora OLDTXT+1
-	bne !-                                       // branch if pointer not NULL
-
-	// Correct VARTAB by 2 bytes NULL pointer
-
-#if HAS_OPCODES_65CE02
-
-	inw VARTAB
-	inw VARTAB
-
-#else
-
-	clc
-	lda VARTAB+0
-	adc #$02
-	sta VARTAB+0
-	bcc !+
-	inc VARTAB+1
-!:
-#endif
-
-	// Call CLR to restore remaining variables
-
-	jsr do_clr
+	jsr calculate_VARTAB
 
 	// Quit
 

src/basic/basic_shift_mem_down.s

@@ -114,9 +114,9 @@ basic_shift_mem_down_and_relink:
 
 	
 relink_down_next_line:
-	// inc $d020
-	// jmp relink_down_next_line
-	
+
+	// XXX reuse code from cmd_old
+
 	// Subtract __tokenise_work3 from the pointer
 	ldy #0
 

src/basic/basic_shift_mem_up.s

@@ -128,8 +128,8 @@ basic_shift_mem_up_and_relink:
 #endif
 	
 relink_up_next_line:
-	// inc $d020
-	// jmp relink_up_next_line
+
+	// XXX reuse code from cmd_old
 	
 	// Advance pointer by tokenise_word3 bytes
 	ldy #0

src/basic/editor/calculate_vartab.s

@@ -0,0 +1,47 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+//
+// Calculate the VARTAB value - to mark the end of BASIC program code
+//
+
+calculate_VARTAB:
+
+	lda TXTTAB+0
+	sta OLDTXT+0
+	lda TXTTAB+1
+	sta OLDTXT+1
+!:
+	lda OLDTXT+0
+	sta VARTAB+0
+	lda OLDTXT+1
+	sta VARTAB+1
+
+	jsr basic_follow_link_to_next_line
+
+	lda OLDTXT+0
+	ora OLDTXT+1
+	bne !-                                       // branch if pointer not NULL
+
+	// Correct VARTAB by 2 bytes NULL pointer
+
+#if HAS_OPCODES_65CE02
+
+	inw VARTAB
+	inw VARTAB
+
+#else
+
+	clc
+	lda VARTAB+0
+	adc #$02
+	sta VARTAB+0
+	bcc !+
+	inc VARTAB+1
+!:
+#endif
+
+	// Call CLR to set-up remaining variables
+
+	jmp do_clr