From 550aceee231ed3b9f55af90ca1142b507747dd4c Mon Sep 17 00:00:00 2001
From: Andrew Alderwick <andrew@alderwick.co.uk>
Date: Sat, 19 Feb 2022 00:28:03 +0000
Subject: [PATCH] (uxnasm) Allow writing the 0xffff byte of RAM.

---
 src/uxnasm.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/uxnasm.c b/src/uxnasm.c
index 63d0c18..2a54455 100644
--- a/src/uxnasm.c
+++ b/src/uxnasm.c
@@ -35,7 +35,8 @@ typedef struct {
 
 typedef struct {
 	Uint8 data[LENGTH];
-	Uint16 ptr, length, llen, mlen, rlen;
+	unsigned int ptr, length;
+	Uint16 llen, mlen, rlen;
 	Label labels[512];
 	Macro macros[256];
 	Reference refs[2048];
@@ -193,6 +194,10 @@ writebyte(Uint8 b)
 		fprintf(stderr, "-- Writing in zero-page: %02x\n", b);
 		return 0;
 	}
+	else if(p.ptr > 0xffff) {
+		fprintf(stderr, "-- Writing after the end of RAM: %02x\n", b);
+		return 0;
+	}
 	else if(p.ptr < p.length) {
 		fprintf(stderr, "-- Memory overwrite: %04x -> %04x\n", p.length, p.ptr);
 		return 0;