Actually, yes, there is quite a lot missing.
You need to use DDRA (Data Direction Port A) to set the port's bits as inputs or outputs. It's just like TRISA in PICs, only I think it's opposite. Check this, but I remember 1=output and 0=input.
Don't forget to disable the COP (like the WDT in PICs). And set your stack pointer first thing. You can see examples of this stuff in the servo source code in the last message of the thread listed at the bottom of this message.
Do you have the Pink Book? Again, foggy memory tells me that there's a Reference Manual (the Pink Book) and a Programmer's Manual. You NEED them! Scratch around on the net and you'll find free e-versions of them. EDIT: Ah, **broken link removed**.
I have tons of HC11s and a few HC12s, but my memory is very bad on them. Haven't used a HC11 in years.
EDIT: Scratch that.
Helped a guy with servo code for HC11 last year. Wrote it on my
MicroStamp 11.