From 9d811e1267e725d5c4f63cb10061edaa863b3408 Mon Sep 17 00:00:00 2001
From: ISSOtm <eldredhabert0@gmail.com>
Date: Sun, 9 Feb 2020 22:13:16 +0100
Subject: [PATCH] Warn when truncating values in `charmap`

---
 src/asm/asmy.y | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/asm/asmy.y b/src/asm/asmy.y
index 52de18cf..d5c5ea96 100644
--- a/src/asm/asmy.y
+++ b/src/asm/asmy.y
@@ -999,7 +999,12 @@ incbin		: T_POP_INCBIN string
 
 charmap		: T_POP_CHARMAP string comma const
 		{
-			if (charmap_Add($2, constexpr_GetConstantValue(&$4) & 0xFF) == -1) {
+			int32_t value = constexpr_GetConstantValue(&$4);
+
+			if ((value & 0xFF) != value)
+				warning(WARNING_TRUNCATION, "Expression must be 8-bit");
+
+			if (charmap_Add($2, value & 0xFF) == -1) {
 				fprintf(stderr, "Error parsing charmap. Either you've added too many (%i), or the input character length is too long (%i)' : %s\n", MAXCHARMAPS, CHARMAPLENGTH, strerror(errno));
 				yyerror("Error parsing charmap.");
 			}