diff --git a/assembler/src/lex.l b/assembler/src/lex.l
index 97b9c3d2..1ed2d9ea 100644
--- a/assembler/src/lex.l
+++ b/assembler/src/lex.l
@@ -64,7 +64,7 @@ int saved_state = INITIAL;
 "jmpi" { yylval.integer = BRW_OPCODE_JMPI; return JMPI; }
 "if" { yylval.integer = BRW_OPCODE_IF; return IF; }
 "iff" { yylval.integer = BRW_OPCODE_IFF; return IFF; }
-"while" { yylval.integer = BRW_OPCODE_NOP; return NOP; }
+"while" { yylval.integer = BRW_OPCODE_WHILE; return WHILE; }
 "send" { yylval.integer = BRW_OPCODE_SEND; return SEND; }
 "else" { yylval.integer = BRW_OPCODE_ELSE; return ELSE; }
 "break" { yylval.integer = BRW_OPCODE_BREAK; return BREAK; }