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Calling SYS and BB4W OS Routines from Assembler
« Thread started on: Nov 23rd, 2008, 6:55pm »
Calling SYS and BB4W OS Routines from Assembler =====================================
I have some code that contains CALLs to BB4W OS Routines (mostly "Oswrch"), using CALL "oswrch", etc.
Rather than having the Assembler code built into the Program and assembled everytime it is run (duplication of space "source and code") I plan to assemble the code, save it into a separate file, then load it into DIMed memory and call the required routines from the program.
In fact, I have some 40+ assembly code routines I use to get some functions/tasks execute faster and rather than calling them through a source code library and assembling them everytime the program is run, I plan to build them as one code file with entry points (Jump) table header so that they can be used as an assembly code library.
My question, is that: as some of the code contains calls to Oswrch type routines (I assume the same also applies to SYS calls), will these calls work when the code is loaded into memory and executed.
The reason for asking, is that I have noticed that the CALL "oswrch" instruction uses the opcode "E8" which means "call procedure with displacement relative to next instruction". Which means that the offset following the opcode is an offset to the interpreter internal "osworch" code or the SYS code.
Appreciate if someone can confirm this, and what possible alternatives can be used to be able to build a standalone library code that can be loaded into memory and executed.
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