; MWM driver implemetation code                                NWO  1999

	       .LABEL  20

EXT_BIO 	EQU	#FFCA	; Extended Bios entry
WAVESEG 	equ	0FB1Eh	; Mapper segement where the replayer is stored

; Jump Table

MWM_Load	equ	#4000
MWK_Load	equ	MWM_Load+3
Play_music	equ	MWK_Load+3
Stop_music	equ	play_music+3
Cont_music	equ	stop_music+3
Fade_music	equ	cont_music+3
Alloc_segs	equ	fade_music+3
Free_segs	equ	alloc_segs+3
MWM_info	equ	free_segs+3
MWM_address	equ	mwm_info+3
driver_info	equ	mwm_address+3

;Driver vars.

banks		equ	driver_info + 3
sram_size	equ	banks + 256
DOSJmpTab	equ	sram_size + 2
play_busy	equ	DOSJmpTab + 2
songdata_bank1	equ	play_busy + 1
songdata_bank2	equ	songdata_bank1 + 1
songdata_bank3	equ	songdata_bank2 + 1
songdata_adres	equ	songdata_bank3 + 1
play_pos	equ	songdata_adres + 2
play_step	equ	play_pos + 2
status		equ	play_step + 2
step_buffer	equ	status + 2
load_buffer	equ	step_buffer + 25


MUSIC.INIT_DRIVER
		macro
		call	check_if_inst
		ld	de,not_installed_txt
		scf
		jp	nz,driver_not@sym
		call	Get_doscall
		or     a,a
driver_not@sym
		endm

MUSIC.PLAY	macro	@bank
		if	"@bank">""
		ld	a,@bank
		endif
		call	play_it
		endm


MUSIC.STOP	macro
		call	stop_it
		endm

MUSIC.CONT	macro
		call	cont_it
		endm

MUSIC.FADE	macro	@fade_speed
		ld	a,@fade_speed
		ld	ix,Alloc_segs
		call	call_seg
		endm

MUSIC.MWM.LOAD	macro	@bank,@file
		ld	a,@bank
		if	"@file">""
		ld	de,file@sym
		endif
		call	Loadmwm
		if	"@file">""
		jr	done@sym
file@sym	db	"@file",0
done@sym
		endif
		endm

MUSIC.MWK.LOAD	macro	@file
		if	"@file">""
		ld	de,file@sym
		endif
		call	Loadmwk
		if	"@file">""
		jr	done@sym
file@sym	db	"@file",0
done@sym
		endif
		endm

MUSIC.ALLOC	macro	@segments
		ld	b,@segments
		ld	ix,Alloc_segs
		call	call_seg
		endm

MUSIC.FREE	macro
		ld	ix,free_segs
		call	call_seg
		endm

MUSIC.MWM.INFO	macro	@song_name
		ld	de,@song_name
		ld	ix,MWM_info
		call	call_seg
		endm

MUSIC.ADDRESS	macro	@address
		if	"@address">""
		ld	de,@address
		endif
		ld	ix,MWM_address
		call	call_seg
		endm

; IN  -
; OUT - ADE = Driver version number (example: a="1" and DE="00" = 1.00).
;        HL = Sram size in KB.

MUSIC.DRIVER_INF
		macro
		ld	ix,driver_info
		call	call_seg
		endm


MUSIC.DRIVER	macro
Loadmwm
		ld	ix,MWM_Load
		jp	call_seg
Loadmwm
		ld	ix,MWK_Load
		jp	call_seg
play_it
		ld	ix,Play_music
		jp	call_seg
stop_it
		ld	ix,Stop_music
		jp	call_seg
cont_it
		ld	ix,Cont_music
		jp	call_seg

Get_doscall:
		xor	a
		ld	de,4*256+2
		call	EXT_BIO
		ld	a,c
		ld	bc,#0C
		add	hl,bc
		ld	de,jump_to
		ld	bc,3
		ldir
		ret

; Check if replayer is installed
; output: if nz=0 not installed
;         if  z=1 installed

check_if_inst:
		ld	hl,id_FB04h
		ld	de,0fb04h+21
		ld	b,5
check_if_inst0:
		ld	a,(de)
		cp	(hl)
		ret	nz
		inc	hl
		inc	de
		djnz	check_if_inst0
		ret


call_seg	ld	iy,(WAVESEG-1)
jump_to 	jp	#f200

id_FB04h:	db	"MBTSR"	; If this is on address FB04h+21
not_installed_txt:
		db	"*** Wavedriver TSR not installed!",13,10,"$"
		endm