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Mairtrus's Photo
Group:
Tech Member: Tech Members
Active Posts:
28 (0.01 per day)
Most Active In:
Engineering & Reverse Engineering (22 posts)
Joined:
24-February 08
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User is offline Apr 17 2013 08:52 AM
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My Information

Member Title:
Get a load of this!!
Age:
24 years old
Birthday:
September 3, 1988
Gender:
Male Male
Location:
Mendoza, Argentina
Interests:
My career. The music, I love make and heard music. Play the guitar. The reverse engineering of whatever that catch my atention.

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Website:
Website  http://

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Project:
Sonic Z. The Z DOESN'T means nothing.
National Flag:
ar

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Posts I've Made

  1. In Topic: SMPS68k RAM Area

    30 June 2010 - 05:59 PM

    I toke the time to fully research the 68K SMPS like 2 years ago (but for lazyness I never published my discoveries), so I can say that some of your notes are a bit inaccurate. The real channels distribution is:
    CODE
    F040-F07F PCM
    F070-F09F FM1
    F0A0-F0CF FM2
    F0D0-F0FF FM3
    F100-F12F FM4
    F130-F15F FM5
    F160-F18F FM6
    F190-F1BF PSG1
    F1C0-F1EF PSG2
    F1F0-F21F PSG3/NOISE

    F220-F24F SFX FM3
    F250-F27F SFX FM4
    F280-F2AF SFX FM5
    F2B0-F2DF SFX PSG1
    F2E0-F30F SFX PSG2
    F310-F33F SFX PSG3
    F340-F36F SFX FM4 (only used by waterfall, I believe)
    F370-F39F SFX PSG (set each time a SFX uses the Noise channel)

    F3A0-F??? Mirror of the musica data (not sure about the SFX data) when the Extra Life music is being played.


    And the structure of each channel is:
    CODE
    00 = bitfield (explained down) (byte)
    01 = channel identifier (6,0,1,2,4,5,6 for the DAC/FM1,2,3,4,5,6 respectively; 80,A0,C0,E0 for the PSG1,2,3,Noise respectively) (byte)
    02 = particular tempo modifier (byte)
    04 = current offset (long)
    08 = pitch (byte)
    09 = volumen (byte)
    0A = channel configuration (stereo/AMS/FMS) (byte)
    0B = instrument/voice (byte)
    0C = offset adder for the current PSG voice (byte)
    0D = return counter. determines in what adress INSIDE THE CHANNEL is the return offset used by the flag E3. 30 is at the end of channel (should NOT execute a return), 2E is 2 bytes before the end of the channel, etc (byte)
    0E = counter of the current note duration (byte)
    0F = current note duration (byte)
    10 = current frequency (word)
    12 = counter of the current note filler (byte)
    13 = current note filler (byte)
    14 = offset of parameters of the last used modulation (long)
    18 = wait time until the modulation starts (byte)
    19 = modulation speed (byte)
    1A = how much the frequency change per modulation step (signed byte)
    1B = maximun amplitude of modulation (byte)
    1C = the adder who modifies the current frequency to produce the modulation (word)
    1E = RAW LSB to be added at the frequency (flag E1) (byte)
    1F = Feedback/Algorithm of the current instrument (FM); kind of sound produce by the Noise channel (if PSG,flag F3) (byte)
    20 = particular offset of the instruments (only used by the SFX FM) (long)

    And the bitfield in the header means this:
    CODE
    Bit 0: Reduntant/Without usage
    Bit 1: 0: There is a note. 1: There is a rest
    Bit 2: (For FM/PSG) 0: Nothing playing over this channel. 1: A high priority sound (a SFX) is over this channel.
    (For DAC): 0: Fade In/Out to the last music is inactive. 1: Fade In/Out to the last music is active (flag E4)
    Bit 3: 0: Modulation inactive. 1: Modulation active
    Bit 4: 0: The Key Off event ocurrs. 1: The Key Off event DOESN'T ocurrs (Key On during the whole note) (flag E7)
    Bit 5: Reduntant/Without usage
    Bit 6: Reduntant/Without usage
    Bit 7: 0: This channel is inactive. 1: This channel is active.

  2. In Topic: SMPS Player with Visuals (Preview)

    27 April 2010 - 03:48 PM

    QUOTE (Andlabs @ Apr 27 2010, 03:15 PM)
    The Z80 driver in Sonic 1 resamples the existing timpani sample if the number is above $87. This is done using special entries in the DAC table. For what it's worth you probably shouldn't be modifying the Sonic 1 DAC driver if you want something truly general purpose. Use jman2050's driver or write a new DAC driver instead.

    Wrong. The "special cases" are handled by the M68K, specifically by the routine loc_71CAC. It looks something like this:
    Syntax Highlighted Code: ASM
    		btst	#3,d0			; it's a special timpani?
    		bne.s	loc_71CAC		; if yes, branch...
    		move.b	d0,($A01FFF).l		; writes the sample's number into the Z80 RAM
     
    locret_71CAA:
    		rts				; leave...
    ; ===========================================================================
     
    loc_71CAC:
    		subi.b	#$88,d0			; adjusts to the correct number
    		move.b	Timpani_Pitches(pc,d0.w),d0 ; loads the modified pitch for the timpani
    		move.b	d0,($A000EA).l		; modifies the pitch
    		move.b	#$83,($A01FFF).l	; plays the normal timpani
    		rts				; leave...
    ; End of function Sound_PlayDAC
     
    ; ===========================================================================
    Timpani_Pitches: dc.b $12, $15, $1C, $1D, $FF, $FF

    In other words, the engine just modifies the current pitch asociated to the (unique) timpani entry in the DAC table in the Z80 code. You only need to cut off the lines above to erase that restriction...

  3. In Topic: SMPS Player with Visuals (Preview)

    22 April 2010 - 07:17 PM

    QUOTE (Andlabs @ Apr 22 2010, 12:05 PM)
    Then it's easy: just find where the effects are handled, set a flag in RAM, then clear it when a new song is played.

    Or even easier, check the location $FFF1F1. If the value is $E0, you have the NOISE. Whatever else (I think it's $C0), it's the PSG 3. Aditionally, the bit 7 at $FFF040 controlls if the DAC channel is activated or not. The same bit at $FFF160 do the same function for the FM6. Understandable?

  4. In Topic: Basic Questions & Answers thread

    17 February 2010 - 10:00 AM

    Exists any information of the music format used in the Sonic Advance series?

  5. In Topic: SMPS PSG Voice envelopes

    04 February 2010 - 06:28 PM

    Both are right. Here is the commented part of SMPS code that manages the atenuation(sub_72926 in whatever disassembly):
    Syntax Highlighted Code: ASM
    DoPSGInstrument:				; XREF: Sound_PlayPSG
    		tst.b	$B(a5)		; is zero the current instrument?
    		beq.w	locret_7298A	; if yes, branch...
     
    DoPSGInstrument_2:				; XREF: Sound_PlayPSG
    		move.b	9(a5),d6	; load the volume
    		moveq	#0,d0
    		move.b	$B(a5),d0	; load the number of instrument 
    		beq.s	PSG_ChgVolume	; is zero (again)?. If yes, branch...
    		movea.l	(Go_PSGIndex).l,a0 ; loads the PSG instruments offset
    		subq.w	#1,d0
    		lsl.w	#2,d0		; get the fixed index
    		movea.l	(a0,d0.w),a0	; load the current offset of the instrument
    		move.b	$C(a5),d0	; load the instrument's counter
    		move.b	(a0,d0.w),d0	; load the modifier byte
    		addq.b	#1,$C(a5)	; augment the counter
    		btst	#7,d0		; is a negative value?
    		beq.s	loc_72960	; if not, branch...
    		cmpi.b	#$80,d0		; is specificly $80?
    		beq.s	LoopPSGInstrument ; if yes branch...
     
    loc_72960:
    		add.w	d0,d6		; modifies the volume
    		cmpi.b	#$10,d6		; is it higher than the maximun (phisically, the lowest) PSG volume?
    		bcs.s	PSG_ChgVolume	; if not, branch...
    		moveq	#$F,d6		; set the maximun (lower) volume
    ; End of function DoPSGInstrument
     
    [...]
     
    LoopPSGInstrument:				; XREF: DoPSGInstrument
    		subq.b	#1,$C(a5)	; decreases the counter (loops it at the last byte)
    		rts

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