Originally posted by: F1.EGS@ISUMVS.BITNET ("E. G. Schnoebelen")
Posted: Wed Nov 5 23:01:32 1986
Date-Received: Tue, 11-Nov-86 06:27:46 EST
Organization: The ARPA Internet
Re: Apple /// SOS and Apple // ProDOS
Software written on one of the operating systems will not run on the
other without a change in the format of the operating system calls
and a recompilation on the other OS.
ProDOS uses a 4 byte sequence in this format :
JSR MLI ; goto the OS entry point.
; byte specifying what is to be done.
SOS on the other hand uses a two byte sequence as follows:
BRK ;Jump to the OS through the interrupt routine.
; byte specifying the OS operation.
The OS opcodes are the same between SOS and ProDOS, so the only changes
needed to switch OS's is to change the JSR MLI to a BRK or visa-versa.
The above can be found in the ProDOS Technical Reference Manual ( I don't
remember what pages, It's not here ) and in the SOS Technical Reference
Manual ( I was remembering from SOS 1.3 ).
Standard Disclaimers apply -- I work for no one, except maybe myself.