diff --git a/twasm/.bootle/disk b/twasm/.bootle/disk
new file mode 100644
index 0000000..189ce17
Binary files /dev/null and b/twasm/.bootle/disk differ
diff --git a/twasm/asm/main.asm b/twasm/asm/main.asm
index 8cab49e..f6828a9 100644
--- a/twasm/asm/main.asm
+++ b/twasm/asm/main.asm
@@ -120,7 +120,7 @@ assemble:
     ; di = next tte
     call get_opcode
     ; al = opcode
-    mov [.pending_operator_opcode], al ; save it fttb
+    mov [.pending_operator_opcode], al ; save opcode fttb
     pop rdi
 
     pop rax ; from start of label .operator
@@ -142,7 +142,11 @@ assemble:
                                              ; of 2 args, it could also be the
                                              ; last of 1
 
-    ; otherwise, quietly discard the token, reset things, and keep going :/
+    ; otherwise, discard the token, reset things, and keep going :/
+    push rsi
+    mov rsi, .warn_unexpected_register
+    call print.warn
+    pop rsi
     call .reset_state
     jmp .continue_register
 
@@ -192,6 +196,10 @@ assemble:
   .break:
     ret
 
+  ; constants
+
+  .warn_unexpected_register db "ignoring unexpected register", 0x0A, 0x00
+
   ; procedures
 
   ; al = byte to write
@@ -212,11 +220,11 @@ assemble:
     ret
 
   .reset_state:
-    ; I don't actually know if these `word` and `byte` directives are needed
+    ; I don't actually know if these `word` directives are needed
     ; TODO check that. I think they are, becasue Nasm doesn't record the size
     ; of labels?
     mov word [.pending_operator_opcode], UNRECOGNISED_TOKEN_ID
-    mov byte [.pending_operator_num_args], 0x00
+    mov [.pending_operator_num_args], 0x00
     mov word [.first_argument], UNRECOGNISED_TOKEN_ID
     ret