The COLD subroutine - Elite on the BBC Micro and NES

       Name: COLD                                                    [Show more]
       Type: Subroutine
   Category: Save and load
    Summary: Set the standard BRKV handler for the game
    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:
             * S% calls COLD


.COLD

 LDA #LO(NEWBRK)        \ Set BRKV to point to the NEWBRK routine
 STA BRKV
 LDA #HI(NEWBRK)
 STA BRKV+1

 LDA #LO(CHPR)          \ Set WRCHV to point to the CHPR routine
 STA WRCHV
 LDA #HI(CHPR)
 STA WRCHV+1

 JSR setzp              \ Call setzp to copy the top part of zero page into
                        \ the buffer at &3000

 JSR SETINTS            \ Call SETINTS to set various vectors, interrupts and
                        \ timers

 JMP SOFLUSH            \ Call SOFLUSH to reset the sound buffers and return
                        \ from the subroutine using a tail call

IF _SNG47

.NMIpissoff

 CLI                    \ These instructions are never reached and have no
 RTI                    \ effect

ENDIF

[X]

Configuration variable BRKV = &0202

The break vector that we intercept to enable us to handle and display system errors

[X]

Subroutine CHPR (category: Text)

Print a character at the text cursor by poking into screen memory

[X]

Subroutine NEWBRK (category: Utility routines)

The standard BRKV handler for the game

[X]

Subroutine SETINTS (category: Loader)

Set the various vectors, interrupts and timers

[X]

Subroutine SOFLUSH (category: Sound)

Reset the sound buffer and turn off all sound channels

[X]

Configuration variable WRCHV = &020E

The WRCHV vector that we intercept to implement our own custom OSWRCH commands for communicating over the Tube

[X]

Subroutine setzp (category: Utility routines)

Copy the top part of zero page (&0090 to &00FF) into the buffer at &3000

Save and load: COLD

[BBC Master version]