[9fans] 8c assembler syntax

[Steve Simon]

I am struggling with the plan9 assembler syntax
and its error messages, Anyone spot my silly?

This is my code

        TEXT    count_leading_zeros+0(SB),0,$0
        MOVL    n+0(FP),BX
        BSRL    BX,AX
        MOVL    $31,BX
        SUB             BX,AX
        RET             ,

which gives

        larch% 8a plan9-386.c
        plan9-386.c:7 syntax error, last name: BX
        line:  LNAME.: $$5 line 
        inst:  LNAME.= expr 
        saw LLREG

Thanks for any help.

-Steve