From bc5e3cdbb9ea27ba03c8624f3e43444d7cccb340 Mon Sep 17 00:00:00 2001
From: Paul Gardner-Stephen <paul@servalproject.org>
Date: Mon, 29 Apr 2019 21:00:00 +0930
Subject: [PATCH] Fix Issue #15

---
 c64/basic/basic_shift_mem_up.s | 35 ++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/c64/basic/basic_shift_mem_up.s b/c64/basic/basic_shift_mem_up.s
index c5731047..0a4cb357 100644
--- a/c64/basic/basic_shift_mem_up.s
+++ b/c64/basic/basic_shift_mem_up.s
@@ -4,6 +4,8 @@ basic_shift_mem_up_and_relink:
 	;; Shift memory up from basic_current_line_ptr
 	;; X bytes.
 
+	;; NOTE: Pointers need to be reduced by one, due to the way
+	;; the copyroutine works, so we do that here.
 	;; Work out end point of destination
 	txa
 	clc
@@ -12,10 +14,21 @@ basic_shift_mem_up_and_relink:
 	lda basic_end_of_text_ptr+1
 	adc #0
 	sta memmove_dst+1
+	lda memmove_dst+0
+	sec
+	sbc #1
+	sta memmove_dst+0
+	lda memmove_dst+1
+	sbc #0
+	sta memmove_dst+1
+
 	;; End point of source is just current end of BASIC text
 	lda basic_end_of_text_ptr+0
+	sec
+	sbc #1
 	sta memmove_src+0
 	lda basic_end_of_text_ptr+1
+	sbc #0
 	sta memmove_src+1
 
 	;; Work out size of region to copy
@@ -67,6 +80,7 @@ basic_shift_mem_up_and_relink:
 	
 	;; Then set Y to the number offset required
 	ldy memmove_size+0
+	iny
 
 	stx tokenise_work3
 	
@@ -102,16 +116,36 @@ relink_up_next_line:
 	;; inc $d020
 	;; jmp relink_up_next_line
 	
+	;; Advance pointer by tokenise_word3 bytes
 	ldy #0
 	ldx #<basic_current_line_ptr+0
 	jsr peek_under_roms
+	sta memmove_dst+0
 	clc
 	adc tokenise_work3
 	sta memmove_src+0
 	iny
+	php
 	jsr peek_under_roms
+	sta memmove_dst+1
+	plp
 	adc #0
 	sta memmove_src+1
+
+	;; jsr printf
+	;; .byte "LINE ADDR = $"
+	;; .byte $f1,<basic_current_line_ptr,>basic_end_of_text_ptr
+	;; .byte $f0,<basic_current_line_ptr,>basic_end_of_text_ptr
+	;; .byte $d,"  BEFORE = $"
+	;; .byte $f1,<memmove_dst,>memmove_dst
+	;; .byte $f0,<memmove_dst,>memmove_dst	
+	;; .byte ",  AFTER = $"
+	;; .byte $f1,<memmove_src,>memmove_src
+	;; .byte $f0,<memmove_src,>memmove_src
+	;; .byte $d
+	;; .byte 0
+	
+	;; Write memmove_src back to current line pointer
 	ldy #0
 	ldx #<basic_current_line_ptr
 	lda memmove_src+0
@@ -120,6 +154,7 @@ relink_up_next_line:
 	lda memmove_src+1
 	jsr poke_under_roms
 
+	
 relink_up_loop:	
 	;; Now advance pointer to the next line,
 	lda memmove_src+0