diff --git a/src/game/insn_disasm.c b/src/game/insn_disasm.c
index c2dfb31a..3e679397 100644
--- a/src/game/insn_disasm.c
+++ b/src/game/insn_disasm.c
@@ -21,15 +21,15 @@ extern far char *parse_map(u32);
 static char insn_as_string[100];
 
 typedef struct __attribute__((packed)) {
-    u8 rd        : 5;
-    u8 shift_amt : 5;
-    u8 function  : 6;
+    u16 rd        : 5;
+    u16 shift_amt : 5;
+    u16 function  : 6;
 } RTypeData;
 
 typedef struct __attribute__((packed)) {
-    u8 opcode : 6;
-    u8 rs     : 5;
-    u8 rt     : 5;
+    u16 opcode : 6;
+    u16 rs     : 5;
+    u16 rt     : 5;
     union {
         RTypeData rdata;
         u16 immediate;
@@ -44,8 +44,8 @@ typedef union {
 typedef struct __attribute__((packed)) {
     u32 type;
     u32 arbitraryParam;
-    u8 opcode   : 6;
-    u8 function : 6;
+    u16 opcode   : 6;
+    u16 function : 6;
     u8 name[10];
 } InsnTemplate;