help with LAP op-codes

[Guy]

I'm writting a complete LAP (List Assembly Program) manual.
on the release, the manual will contain:
a LAP assembler, Brief Instruction manual, byte-code decoding manual,
more...

I'm missing pieces of information, information which I couldn't find 
elsewhere.

I'll be gratefull if someone could help...

1) what's the purpose of op-code 90 (\132) the instruction byte-diff ?

2) what's the purpose of op-codes, and what arguments do they take on stack?

 \220     byte-temp-output-buffer-setup
 \221     byte-temp-output-buffer-show
 \217     byte-condition-case

                  thanks

                                   Guy.