screen editor now supports tabulators

c64/kernal/screen/chrout_screen_crsr.s

@@ -12,6 +12,7 @@ chrout_screen_CRSR_UP:
 	sta PNTR
 	jmp chrout_screen_calc_lptr_done
 
+
 chrout_screen_CRSR_DOWN:
 
 	lda PNTR
@@ -25,15 +26,17 @@ chrout_screen_CRSR_DOWN:
 	jsr screen_scroll_up_if_on_last_line
 	jmp chrout_screen_calc_lptr_done
 
+
 chrout_screen_CRSR_LEFT:
 
 	lda TBLX
 	ora PNTR
-	beq !+ // recalculating pointer is not really necessary, but this is a very rare case nevertheless
+	beq !+ // top-left corner, recalculating pointer is not necessary, but this is a very rare case nevertheless
 	dec PNTR
 !:
 	jmp chrout_screen_calc_lptr_done
 
+
 chrout_screen_CRSR_RIGHT:
 
 	inc PNTR

c64/kernal/screen/chrout_screen_jumptable_codes.s

@@ -24,6 +24,10 @@ __chrout_screen_jumptable_quote_guard:
 
 #if CONFIG_EDIT_STOPQUOTE
 	.byte KEY_STOP
+#endif
+#if CONFIG_EDIT_TABULATORS
+	.byte KEY_TAB_BW
+	.byte KEY_TAB_FW
 #endif
 	.byte KEY_INS
 	.byte KEY_DEL
@@ -48,6 +52,10 @@ chrout_screen_jumptable_lo:
 	.byte <(chrout_screen_CRSR_UP    - 1)
 #if CONFIG_EDIT_STOPQUOTE
 	.byte <(chrout_screen_STOP       - 1)
+#endif
+#if CONFIG_EDIT_TABULATORS
+	.byte <(chrout_screen_TAB_BW     - 1)
+	.byte <(chrout_screen_TAB_FW     - 1)
 #endif
 	.byte <(chrout_screen_INS        - 1)
 	.byte <(chrout_screen_DEL        - 1)
@@ -69,6 +77,10 @@ chrout_screen_jumptable_hi:
 	.byte >(chrout_screen_CRSR_UP    - 1)
 #if CONFIG_EDIT_STOPQUOTE
 	.byte >(chrout_screen_STOP       - 1)
+#endif
+#if CONFIG_EDIT_TABULATORS
+	.byte >(chrout_screen_TAB_BW     - 1)
+	.byte >(chrout_screen_TAB_FW     - 1)
 #endif
 	.byte >(chrout_screen_INS        - 1)
 	.byte >(chrout_screen_DEL        - 1)

c64/kernal/screen/chrout_screen_tab.s

@@ -0,0 +1,33 @@
+
+//
+// Tabulation keys handling within CHROUT
+//
+
+
+#if CONFIG_EDIT_TABULATORS
+
+
+chrout_screen_TAB_FW:
+
+	lda PNTR
+	ora #%00000111
+	sta PNTR
+	inc PNTR
+	jmp chrout_screen_calc_lptr_done
+
+
+chrout_screen_TAB_BW:
+
+	lda TBLX
+	ora PNTR
+	beq !+ // top-left corner, recalculating pointer is not necessary, but this is a very rare case nevertheless
+
+	dec PNTR
+	lda PNTR
+	and #%11111000
+	sta PNTR
+!:
+	jmp chrout_screen_calc_lptr_done
+
+
+#endif // CONFIG_EDIT_TABULATORS