From c7db426bd39393bfa8cdb8a38ae98c9d90562caf Mon Sep 17 00:00:00 2001
From: Paul Gardner-Stephen <paul@servalproject.org>
Date: Sun, 28 Apr 2019 22:30:49 +0930
Subject: [PATCH] begin implementing LIST command

---
 c64/basic/basic_find_next_line.s | 15 +++++++++++++
 c64/basic/cmd_list.s             | 38 ++++++++++++++++++++++++++++++++
 c64/basic/cmd_unimplemented.s    |  1 -
 3 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 c64/basic/basic_find_next_line.s
 create mode 100644 c64/basic/cmd_list.s

diff --git a/c64/basic/basic_find_next_line.s b/c64/basic/basic_find_next_line.s
new file mode 100644
index 00000000..f8b6c3d2
--- /dev/null
+++ b/c64/basic/basic_find_next_line.s
@@ -0,0 +1,15 @@
+	;; Advance basic_current_line_ptr by following the
+	;; link to the next line
+
+basic_find_next_line:
+
+	ldy #0
+	ldx #<basic_current_line_ptr
+	jsr peek_under_roms
+	pha
+	iny
+	jsr peek_under_roms
+	sta basic_current_line_ptr+1
+	pla
+	sta basic_current_line_ptr+0
+	rts
diff --git a/c64/basic/cmd_list.s b/c64/basic/cmd_list.s
new file mode 100644
index 00000000..6e416fcb
--- /dev/null
+++ b/c64/basic/cmd_list.s
@@ -0,0 +1,38 @@
+	;; LIST basic text.
+	;; XXX - Doesn't currently support line number ranges
+
+cmd_list:
+
+	;; Set current line pointer to start of memory
+	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
+
+list_loop:
+	ldx #<basic_current_line_ptr
+	ldy #0
+	jsr peek_pointer_null_check
+	bcs list_more_lines
+
+	jmp basic_main_loop
+
+list_more_lines:
+	;; Print line number
+	ldy #3
+	jsr peek_under_roms
+	pha
+	dey
+	jsr peek_under_roms
+	tax
+	pla
+	jsr print_integer
+
+	;; Print end of line
+	lda #$0d
+	jsr $ffd2
+
+	;; Now link to the next line
+	jsr basic_find_next_line
+	jmp list_loop
+	
diff --git a/c64/basic/cmd_unimplemented.s b/c64/basic/cmd_unimplemented.s
index 69fbfc6d..2256914d 100644
--- a/c64/basic/cmd_unimplemented.s
+++ b/c64/basic/cmd_unimplemented.s
@@ -29,7 +29,6 @@ cmd_poke:
 cmd_printhash:
 cmd_print:
 cmd_cont:
-cmd_list:
 cmd_cmd:
 cmd_sys:
 cmd_open: