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Utility routines: NMIRELEASE

[BBC Master version]

Name: NMIRELEASE [Show more] Type: Subroutine Category: Utility routines Summary: Release the NMI workspace (&00A0 to &00A7) so the MOS can use it and store the top part of zero page in the the buffer at &3000
Context: See this subroutine in context in the source code References: This subroutine is called as follows: * CATS calls NMIRELEASE * DELT calls NMIRELEASE * GTDIR calls NMIRELEASE * rfile calls NMIRELEASE * wfile calls NMIRELEASE
IF _COMPACT .NMIRELEASE JSR getzp+3 \ Call getzp+3 to restore the top part of zero page \ from the buffer at &3000, but without first claiming \ the NMI workspace (as it's already been claimed by \ this point) LDA #143 \ Call OSBYTE 143 to issue a paged ROM service call of LDX #&B \ type &B with Y set to the previous NMI owner's ID. LDY NMI \ This releases the NMI workspace back to the original JMP OSBYTE \ owner, from whom we claimed the workspace in the \ NMICLAIM routine, and returns from the subroutine \ using a tail call ENDIF