Texas Instruments 990 Operation Manual page 225

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945255-9701
APPENDIX A
COMPATIBILITY WITH DXI0
A program developed for the Prototyping System may be run under DXIO if several conventions
are followed:
1. The first three words of the program should be:
DATA WP Workspace
DATA START Entry point
DATA END-ACTION Address of point to branch to on an
unrecoverable error
2. The program must be terminated with an end-of-program supervisor call.
3. An open supervisor call should be issued before a read or write to a file-oriented
device.
4. All interrupts are handled by the DXIO operating system.
5. Absolute code, created by an AORG instruction, is loaded with the same load bias as
relocatable code. Code at AORG 0 and RORG 0 are both loaded at the first location
of the user's address space.
A more extensive explanation of these points can be found in the Model 990 Computer DXIO
Operating System Programmer's Guide, Manual No. 945257-9701.
A-l/A-2
Digital Systems Division .