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Elite on the BBC Micro and NES

Utility routines: FX200

[BBC Micro cassette version]

Name: FX200 [Show more] Type: Subroutine Category: Utility routines Summary: Set the behaviour of the ESCAPE and BREAK keys
Context: See this subroutine in context in the source code Variations: See code variations for this subroutine in the different versions References: This subroutine is called as follows: * BR1 (Part 1 of 2) calls FX200 * LOD calls FX200

This is the equivalent of a *FX 200 command, which controls the behaviour of the ESCAPE and BREAK keys.
Arguments: X Controls the behaviour as follows: * 0 = Enable ESCAPE key Normal BREAK key action * 1 = Disable ESCAPE key Normal BREAK key action * 2 = Enable ESCAPE key Clear memory if the BREAK key is pressed * 3 = Disable ESCAPE key Clear memory if the BREAK key is pressed
.FX200 LDY #0 \ Call OSBYTE 200 with Y = 0, so the new value is set to LDA #200 \ X, and return from the subroutine using a tail call JMP OSBYTE RTS \ This instruction has no effect, as we already returned \ from the subroutine