some character insertion fixes

c64/kernal/screen/chrout_screen_ins.s

@@ -4,29 +4,24 @@
 //
 
 
-// YYY does not work properly when insertion no longer possible
+// YYY moves cursor down the first time no more insertion is possible
-// YYY does not work properlyy in second part of logical line
+// YYY in second part of the logical line moves everything froom the start of the line
 
 
 chrout_screen_INS:
 
-	// First check if last character of the line is space
+	// First check if last character of the logiccall line is space
 	
 	jsr screen_check_space_ends_line
 	beq chrout_screen_ins_possible
 
-	// Not space, try to grow logical line and check once again
+	// Not space, we cannot insert anything
 
-	jsr screen_grow_logical_line
-	jsr screen_check_space_ends_line
 	bne_far chrout_screen_calc_lptr_done
-	
-	// FALLTROUGH
 
 chrout_screen_ins_possible:
 
 	// Move chars towards end of the line
-	jsr screen_calculate_PNT_USER
 	jsr screen_get_logical_line_end_ptr
 !:
 	// Note: While the following routine is obvious to any skilled
@@ -57,4 +52,11 @@ chrout_screen_ins_possible:
 	lda #$20
 	sta (PNT), y
 
+	// If line does not end with space now, grow try to grow the logical line
+	
+	jsr screen_check_space_ends_line
+	beq !+
+
+	jsr screen_grow_logical_line
+!:
 	jmp chrout_screen_calc_lptr_done

c64/kernal/screen/screen_check_space_ends_line.s

@@ -1,8 +1,10 @@
-
+
-screen_check_space_ends_line:
+screen_check_space_ends_line:
-
+
-	jsr screen_get_logical_line_end_ptr
+	jsr screen_get_logical_line_end_ptr
-	lda (PNT), y
+
-	cmp #$20
+	lda (PNT), y
-	
+	cmp #$20
-	rts
+
+	rts
+

c64/kernal/screen/screen_get_logical_line_end_ptr.s

@@ -1,25 +1,25 @@
-
+
-
+
-screen_get_logical_line_end_ptr:
+screen_get_logical_line_end_ptr:
-
+
-	ldy TBLX
+	ldy TBLX
-	cpy #24
+	cpy #24
-	bcs screen_get_logical_line_end_39 // last line of the screen
+	bcs screen_get_logical_line_end_39 // last line of the screen
-	
+
-	lda LDTBL+0, y
+	lda LDTBL+0, y
-	bpl screen_get_logical_line_end_39 // current line continues previous one
+	bpl screen_get_logical_line_end_39 // current line continues previous one
-	
+
-	lda LDTBL+1, y
+	lda LDTBL+1, y
-	bmi screen_get_logical_line_end_39 // current line is not continued
+	bmi screen_get_logical_line_end_39 // current line is not continued
-	
+
-	// FALLTROUGH
+	// FALLTROUGH
-	
+
-screen_get_logical_line_end_79:
+screen_get_logical_line_end_79:
-
+
-	ldy #79
+	ldy #79
-	rts
+	rts
-	
+
-screen_get_logical_line_end_39:
+screen_get_logical_line_end_39:
-
+
-	ldy #39
+	ldy #39
 	rts