From 7581717a1a89af758aa7988583623003706a2585 Mon Sep 17 00:00:00 2001
From: nesrocks <31553664+nesrocks@users.noreply.github.com>
Date: Mon, 14 Apr 2025 16:58:19 -0300
Subject: [PATCH] RLE decoder update

This fix proposed by Pinobatch (aka Tepples) aims to improve the decoder compatibility for nametables that have no unused tile, as in all 256 CHR tiles were used.

The improvement consists of the following change: if a read byte is the tag but is followed by a "01" that means the tag won't act as a tag, but as data.

An updated encoder must be used to make full use of the new logic, but this updated version can also be used to fully load previously encoded RLE data that use fewer than 256 tiles.
---
 neslib.sinc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/neslib.sinc b/neslib.sinc
index d37680e..77c17d7 100644
--- a/neslib.sinc
+++ b/neslib.sinc
@@ -562,6 +562,9 @@ _vram_unrle:
 
 	cmp <RLE_TAG
 	beq @2
+
+@is_literal:
+
 	sta PPU_DATA
 	sta <RLE_BYTE
 	bne @1
@@ -576,6 +579,13 @@ _vram_unrle:
 
 @21:
 
+	cmp#$01
+	bcs @is_run
+	lda <_RLE_TAG
+	bcc @is_literal
+
+@is_run:
+
 	tax
 	lda <RLE_BYTE