mirror of https://github.com/a2-4am/4cade.git
187 lines
6.0 KiB
Plaintext
187 lines
6.0 KiB
Plaintext
;license:MIT
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;(c) 2018-9 by 4am
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;
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; Functions to launch games and self-running demos
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;
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; Public functions
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; - PlayGameFromSearch
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; - PlayGameFromAttract
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;
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; Public variables
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; - SelectedIndex ; [byte] numeric index in gGamesStore of currently selected game in search mode
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; - gCurrentAttractIndex ; [byte] numeric index in gAttractModeStore of current Mega-Attract Module
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; - gCurrentlyVisibleSlideshowIndex ; [byte] numeric index in gSlideshowStore of currently visible slideshow picture
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; (only valid during slideshows, not updated once a key is pressed)
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PlayGameFromSearch
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jsr okvs_nth
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!word gGamesListStore
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SelectedIndex
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!byte $FD ; SMC
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jmp Go
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PlayGameFromAttract
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+LDADDR kAttractModeConfFile
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jsr SetPath
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jsr LoadFile ; load attract-mode configuration file at $8000
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jsr ParseKeyValueList ; parse attract-mode configuration into OKVS data structure at $6000
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!word gAttractModeStore
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!word ldrlo2 ; (ldrlo2) points to last load address, so $8000
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!byte 0
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jsr okvs_nth ; get filename of current attract-mode module
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!word gAttractModeStore
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gCurrentAttractIndex
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!byte $FD ; set in AttractMode
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+STAY @key
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jsr okvs_get
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!word gAttractModeStore
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@key !word $FDFD ; SMC
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+STAY PTR
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ldy #1
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lda (PTR),y
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and #$0F
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bne @playFromSlideshow
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; we reached here by pressing <RETURN> during a self-running demo,
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; which means that @key points to the filename of the game we want to play
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+LDAY @key
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jmp Go
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@playFromSlideshow
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; we reached here by pressing <RETURN> during a slideshow
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; gSlideshowStore is still in memory, and gCurrentlyVisibleSlideshowIndex
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; is the index into gSlideshowStore of the picture that is being displayed
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jsr okvs_nth
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!word gSlideshowStore
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gCurrentlyVisibleSlideshowIndex
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!byte $FD ; set in HGRTitleCallback, HGRActionCallback, DHGRTitleCallback
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+STAY @sskey
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+STAY @sskey2
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jsr okvs_get
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!word gGamesListStore
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@sskey !word $FDFD ; SMC
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bcs +
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+LDAY @sskey
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jmp Go
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+
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; if the key is not found, try getting the value of the current record
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; from gSlideshowStore and using that instead
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; (some games have multiple action screenshots, value points to the key in gGamesListStore)
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jsr okvs_get
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!word gSlideshowStore
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@sskey2 !word $FDFD ; SMC
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bcc Go
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rts
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Go
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+STAY PTR
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bit $C010 ; forget the key that was pressed
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ldx #1
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sec
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!byte $2c
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-- pha
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clc
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php
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ldy #0
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lda (PTR), y
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tay
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iny
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sty @runlength+1
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ldy #0
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lda #'X'
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sta ProDOS_prefix+1
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lda #'/'
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- inx
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sta ProDOS_prefix, x
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iny
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lda (PTR), y
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@runlength
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cpy #$D1 ; SMC
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bne -
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txa
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plp
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bcs --
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stx ProDOS_prefix
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+LDADDR ProDOS_prefix
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jsr SetPath
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jsr LoadFile
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pla
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sta ProDOS_prefix
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copy_prelaunch
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+READ_RAM2_WRITE_RAM2
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ldx #1
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- lda $100,x
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sta $DF00,x ; backup stack
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inx
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bne -
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tsx ; backup stack pointer
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stx $DF00
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lda #$38 ; 'sec' opcode
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sta RestoreStackNextTime ; tell |Reenter| to restore stack
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ldx #(End_Prelaunch-Prelaunch-1)
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- lda Prelaunch,x ; copy pre-launch code to main memory
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sta $100,x
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dex
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bpl -
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ldx #(end_promote-promote-1)
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- lda promote,x ; copy ProDOS shim to main memory
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sta $bf00,x
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dex
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bpl -
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jmp $106 ; jump to pre-launch code
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;------------------------------------------------------------------------------
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; Prelaunch
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; code to set up machine for running a self-running, self-terminating game demo
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; DO NOT CALL DIRECTLY
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; must be run from main memory
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; contains multiple entry points
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;
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; in: none
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; out: exits via JMP (ldrlo2), which is expected to exit via JMP |Prelaunch|
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; (not here, but wherever it was copied to in main memory) or by
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; manually enabling LC RAM then JMP |Reenter|
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;------------------------------------------------------------------------------
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Prelaunch ; this runs from main memory
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; entry point used by some self-running demos
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lda $C088
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jmp Reenter
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; entry point to launch game
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+READ_ROM_NO_WRITE
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lda ldrlo2 ; set up game entry point in stack page
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ldy ldrhi2 ; (last load address - 1)
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sec
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sbc #$01
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bcs +
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dey
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+
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+STAY $1FE
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ldx #0 ; wipe zero page
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txa
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- sta $00,x
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inx
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bne -
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lda #$65 ; initialize random seed (some games like Pooyan
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sta $4E ; require these to be non-zero)
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lda #$02
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sta $4F
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jsr $FE89 ; initialize machine like a cold boot (many
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jsr $FE93 ; games assume a 'clean slate' and rely on
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jsr $FE84 ; zero page values set by these ROM routines,
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sta $C000 ; e.g. Wavy Navy just prints out text via $FDED
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sta $C002 ; and expects it to work)
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sta $C004
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sta $C00C
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sta $C00E
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jsr $FB2F
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jsr $FC58
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ldx #$FD ; jump to game entry point via stack pop
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txs
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rts
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End_Prelaunch
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