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Elite on the BBC Micro and NES

Drawing circles: DOHFX

[6502 Second Processor version, I/O processor]

Name: DOHFX [Show more] Type: Subroutine Category: Drawing circles Summary: Implement the #DOHFX <flag> command (update the hyperspace effect flag)
Context: See this subroutine in context in the source code References: This subroutine is called as follows: * JMPTAB calls DOHFX

This routine is run when the parasite sends a #DOHFX <flag> command. It updates the hyperspace effect flag in HFX.
Arguments: A The new value of the hyperspace effect flag: * 0 = no colour effect * Non-zero = enable hyperspace colour effect
.DOHFX STA HFX \ Store the new hyperspace effect flag in HFX JMP PUTBACK \ Jump to PUTBACK to restore the USOSWRCH handler and \ return from the subroutine using a tail call