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Elite on the BBC Micro and NES

Utility routines: NMICLAIM

[BBC Master version]

Name: NMICLAIM [Show more] Type: Subroutine Category: Utility routines Summary: Claim the NMI workspace (&00A0 to &00A7) back from the MOS so the game can use it once again
Context: See this subroutine in context in the source code References: This subroutine is called as follows: * getzp calls NMICLAIM * setzp calls NMICLAIM
IF _COMPACT .NMICLAIM LDA #143 \ Call OSBYTE 143 to issue a paged ROM service call of LDX #&C \ type &C with argument &FF, which is the "NMI claim" LDY #&FF \ service call that asks the current user of the NMI JSR OSBYTE \ space to clear it out STY NMI \ Save the returned value of Y in NMI, as it contains \ the filing system ID of the previous claimant of the \ NMI, which we need to restore once we have finished \ using the NMI workspace RTS \ Return from the subroutine ENDIF