
RMT 1.x module format
--------------------------------


header struct
=============

offset	type	desc
------	----	----
00	WORD	header string 'RMT4' or 'RMT8'
04	BYTE	track len ($00 means 256)
05	BYTE	song speed
06	BYTE	player freq
07	BYTE	format version number ($01 for player routine 1.x compatible format)
08	WORD	pointer to instruments table
0a	WORD 	pointer to tracks table (lo)
0c	WORD	pointer to tracks table (hi)
0e	WORD	pointer to tracks list (SONG)


instrument struct
=================

offset	type	desc
------	----	----
00	BYTE	tlen (pointer to end of table of notes)
01	BYTE 	tgo (pointer to loop of table of notes)
02	BYTE	elen (pointer to end of envelope)
03	BYTE	ego (pointer to loop of envelope)
04	BYTE	tspd (bit 0-5), tmode (bit 6), ttype (bit 7)
05	BYTE	audctl
06	BYTE	vslide
07	BYTE	vmin(bit 4-7)
08	BYTE	delay ($00 for no vibrato & no fshift)
09	BYTE	vibrato
0a	BYTE	fshift
0b	BYTE	unused
0c		table of notes
?		envelope


TABLE OF NOTES struct
=====================
	BYTE	note or frequence (according to the ttype)


ENVELOPE struct
===============
	BYTE	volume (bit 0-3 left channel) (bits 4-7 right channel (in RMT4 it's the same as bits 0-3))
	BYTE	portamento (bit 0), distortion(bit 1-3), command (bit 4-6), filter (bit 7)
	BYTE	XY


TRACK struct
============

BYTE
	bit 0-5	note
	bit 6-7	volume(LO) or pause(1-3 beats) or special

if note is $00-$3c:
BYTE
	bit 0-1	volume(HI)
	bit 2-7 instrument number

if note is $3d:
BYTE
	bit 0-1	volume(HI)	volume only

if note is $3e:
	bit 6-7 pause
	if pause is $01-$03:	pause 1-3 beats
	if pause is $00:	next byte pause 1-255 beats

if note is $3f:
	if bit 6-7 is zero:	next byte speed $01-$ff
	if bit 6 is zero, 7 is set up:	next byte is track jump pointer (go to $00-$ff from the begin of track data)
	if bit 6-7 is set up:	END of track

INSTRUMENTS TABLE
=================
	WORD	ptr_instr0
	WORD	ptr_instr1
	WORD	ptr_instr3
	...

TRACKS TABLE (LO)
=================
	BYTE	lowbyte_of_ptr_track0
	BYTE	lowbyte_of_ptr_track1
	BYTE	lowbyte_of_ptr_track2
	...

TRACKS TABLE (HI)
=================
	BYTE	highbyte_of_ptr_track0
	BYTE	highbyte_of_ptr_track1
	BYTE	highbyte_of_ptr_track2
	...

TRACK LIST struct (SONG)
========================
	BYTE	tracknumL1,tracknumL2,tracknumL3,tracknumL4,[tracknumR1,..,tracknumR4]
	BYTE	tracknumL1,tracknumL2,tracknumL3,tracknumL4,[tracknumR1,..,tracknumR4]
	BYTE	tracknumL1,tracknumL2,tracknumL3,tracknumL4,[tracknumR1,..,tracknumR4]
	...

if tracknum is FF, then empty track is used

if tracknumL1 is FE, then gotoline(BYTE)=tracknumL2, goto_pointer(WORD)=(tracknumL3,4)
	Note: gotoline(BYTE) is not used in player (but tracker uses it)

