Midway Zeus - Revision history

Aaron at 18:27, 28 December 2007

2007-12-28T18:27:17Z

← Older revision		Revision as of 20:27, 28 December 2007
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	== Midway Zeus Hardware ==		== Midway Zeus Hardware ==
			This topic is primarily focused on the 3D graphics hardware of the Zeus. The Zeus chip is a Midway custom 3D controller that is capable of high polygon rates. Not much is yet known about the chip, but a number of details have been reverse engineered. This page describes what is currently known/understood.

	~~This topic is primarily focused~~ on the ~~3D graphics~~ hardware of the Zeus. The Zeus chip is a Midway custom 3D controller that is capable of high polygon rates. Not much is yet known about the chip, but a number of details have been reverse engineered. This page describes what is currently known/understood.		=== Games ===
			There are two known games running on the Zeus hardware:
			* Mortal Kombat 4
			* Invasion

	=== Main CPU ===		=== Main CPU ===

	The main CPU driving the Zeus is -- at least in the case of Mortal Kombat 4 -- a TMS32C032 DSP running at 60 MHz.		The main CPU driving the Zeus is -- at least in the case of Mortal Kombat 4 -- a TMS32C032 DSP running at 60 MHz.

	=== Zeus 3D Graphics ===		=== Zeus 3D Graphics ===

	The Zeus chip is memory mapped into the main CPU's address space at addresses from $880000-$8803FF. Keep in mind that the TMS32C032 only accesses 32-bit memory, so each of the 1,024 addresses is 32 bits wide (i.e., address $880000 references one 32-bit word, and address $880001 references a completely independent 32-bit word).		The Zeus chip is memory mapped into the main CPU's address space at addresses from $880000-$8803FF. Keep in mind that the TMS32C032 only accesses 32-bit memory, so each of the 1,024 addresses is 32 bits wide (i.e., address $880000 references one 32-bit word, and address $880001 references a completely independent 32-bit word).

Aaron: /* Command $17 */

2007-12-20T02:43:51Z

Command $17

← Older revision		Revision as of 04:43, 20 December 2007
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	Render a model which has been previously configured by the internal data pointers. Invasion uses this; MK4 does not appear to do it this way. It is unknown if anything other than 0 is valid in the low 24 bits of the command word.		Render a model which has been previously configured by the internal data pointers. Invasion uses this; MK4 does not appear to do it this way. It is unknown if anything other than 0 is valid in the low 24 bits of the command word.

	===== Command $17 =====		===== FIFO Command $17 =====
	{\| border="1"		{\| border="1"
	! Bit\|\|31\|\|30\|\|29\|\|28\|\|27\|\|26\|\|25\|\|24\|\|23\|\|22\|\|21\|\|20\|\|19\|\|18\|\|17\|\|16\|\|15\|\|14\|\|13\|\|12\|\|11\|\|10\|\|09\|\|08\|\|07\|\|06\|\|05\|\|04\|\|03\|\|02\|\|01\|\|00		! Bit\|\|31\|\|30\|\|29\|\|28\|\|27\|\|26\|\|25\|\|24\|\|23\|\|22\|\|21\|\|20\|\|19\|\|18\|\|17\|\|16\|\|15\|\|14\|\|13\|\|12\|\|11\|\|10\|\|09\|\|08\|\|07\|\|06\|\|05\|\|04\|\|03\|\|02\|\|01\|\|00

Aaron at 02:43, 20 December 2007

2007-12-20T02:43:25Z

Show changes

Aaron: /* Model Commands */

2007-12-20T02:36:22Z

Model Commands

Show changes

Aaron: /* FIFO Commands */

2007-12-19T15:51:36Z

FIFO Commands

← Older revision		Revision as of 17:51, 19 December 2007
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	This is an extended form of the command which accepts two matrices. The low 16 bits of the command word are set to $7FFF to indicate that we are using the extended form. The two matrices contain 16-bit values in 1.0.15 format, and are multiplied together (''MATRIXB'' x ''MATRIXA''), taking the top 16 bits to give a 1.1.14 value just like the single matrix form. The translation vector is the same format as the regular form.		This is an extended form of the command which accepts two matrices. The low 16 bits of the command word are set to $7FFF to indicate that we are using the extended form. The two matrices contain 16-bit values in 1.0.15 format, and are multiplied together (''MATRIXB'' x ''MATRIXA''), taking the top 16 bits to give a 1.1.14 value just like the single matrix form. The translation vector is the same format as the regular form.

	===== Command $23 =====		===== Command $23/$2E =====
	{\| border="1"		{\| border="1"
	! Bit\|\|31\|\|30\|\|29\|\|28\|\|27\|\|26\|\|25\|\|24\|\|23\|\|22\|\|21\|\|20\|\|19\|\|18\|\|17\|\|16\|\|15\|\|14\|\|13\|\|12\|\|11\|\|10\|\|09\|\|08\|\|07\|\|06\|\|05\|\|04\|\|03\|\|02\|\|01\|\|00		! Bit\|\|31\|\|30\|\|29\|\|28\|\|27\|\|26\|\|25\|\|24\|\|23\|\|22\|\|21\|\|20\|\|19\|\|18\|\|17\|\|16\|\|15\|\|14\|\|13\|\|12\|\|11\|\|10\|\|09\|\|08\|\|07\|\|06\|\|05\|\|04\|\|03\|\|02\|\|01\|\|00
	\|- align="center"		\|- align="center"
	\| '''Word 0'''		\| '''Word 0'''
	\| colspan="8"\| $23		\| colspan="8"\| $23 or $2E
	\| colspan="8"\| 0		\| colspan="8"\| 0
	\| colspan="16"\| XVECTOR		\| colspan="16"\| XVECTOR
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	Some sort of control. Bit 7 of ''VALUE1'' is toggled on each frame. Does this select the page? The other data is completely unknown. It is also strange that MK4 uses $25 and Invasion uses $30, but they both appear to be the same commands. With MK4 the first word is usually $25000000, $25000080, $25008000, or $25800000. The latter two cases expect a total of 10 data words, while the former two expect a total of 4 data words.		Some sort of control. Bit 7 of ''VALUE1'' is toggled on each frame. Does this select the page? The other data is completely unknown. It is also strange that MK4 uses $25 and Invasion uses $30, but they both appear to be the same commands. With MK4 the first word is usually $25000000, $25000080, $25008000, or $25800000. The latter two cases expect a total of 10 data words, while the former two expect a total of 4 data words.

			===== Command $2D/$70 =====
			{\| border="1"
			! Bit\|\|31\|\|30\|\|29\|\|28\|\|27\|\|26\|\|25\|\|24\|\|23\|\|22\|\|21\|\|20\|\|19\|\|18\|\|17\|\|16\|\|15\|\|14\|\|13\|\|12\|\|11\|\|10\|\|09\|\|08\|\|07\|\|06\|\|05\|\|04\|\|03\|\|02\|\|01\|\|00
			\|- align="center"
			\| '''Word 0'''
			\| colspan="8"\| $2D or $70
			\| colspan="24"\| ''UNKNOWN''
			\|}
			This command is rarely used and its purpose is unknown.

			===== Command $67 =====
	{\| border="1"		{\| border="1"
	\|-		! Bit\|\|31\|\|30\|\|29\|\|28\|\|27\|\|26\|\|25\|\|24\|\|23\|\|22\|\|21\|\|20\|\|19\|\|18\|\|17\|\|16\|\|15\|\|14\|\|13\|\|12\|\|11\|\|10\|\|09\|\|08\|\|07\|\|06\|\|05\|\|04\|\|03\|\|02\|\|01\|\|00
	~~!Command~~		\|- align="center"
	~~!Words~~		\| '''Word 0'''
	~~!Format~~		\| colspan="8"\| $25 or $30
	~~!Description~~		\| colspan="8" \| 0
	\|-		\| colspan="16"\| ''UNKNOWN''
	\|~~$23~~		\|- align="center"
	\|2		\| '''Word 1'''
	\|~~<code>~~$~~23aabbbb<br/>~~		\| x\|\|x
	~~$ccccdddd</code>~~		\| colspan="6"\| ''MLENGTH''
	\|~~Specify some other vector (bbbb cccc dddd). It is unknown what this is.~~		\| x
	\|-		\| colspan="11"\| ''MROW''
	\|~~$25/$30~~		\| x\|\|x\|\|x
	\|~~4 or 10~~		\| colspan="9"\| ''MCOLUMN''
	\|~~<code>$25aaaaaa<br/>~~		\|- align="center"
	~~$bbbbbbbb<br/>~~		\| '''Word 2'''
	~~$cccccccc<br/>~~		\| colspan="6"\| ''TEXOFFSHI''
	~~$dddddddd</code>~~		\| colspan="10"\| ''TEXMODE''
	\|		\| colspan="16"\| ''TEXOFFSLO''
	\|-
	\|~~$67~~
	\|3
	\|~~<code>$67aaaaaa<br/>~~
	~~$bbbbbbbb<br/>~~
	~~$cccccccc</code>~~
	\|Render a model stored in Wave RAM. It is unknown if (a) means anything. (b) is a pointer to the model data, with the length of the data in the upper 8 bits and the row/column in the lower 24 bits. (c) specifies information about the texture. The address of the texture in Wave RAM seems to come from bits 0-15 and bits 26-31. The texture mode comes from bits 16~~-25 and controls information such as the texture width and format. Model data is stored in Wave RAM as another sequence of command words that is similar but not identical to the FIFO commands.~~
	\|}		\|}
			Render a model stored in Wave RAM. ''UNKNOWN'' may or may not mean anything. The second word specifies a pointer to model data in wave RAM, using the block form. The texture data is specified in the second word. ''TEXMODE'' describes a texture mode, including information on the texture data width and format. ''TEXOFFSHI'' combines with ''TEXOFFSLO'' to produce the texture row for rendering.

	==== Model Commands ====		==== Model Commands ====

Aaron: /* FIFO Commands */

2007-12-19T15:44:45Z

FIFO Commands

Show changes

Aaron at 15:15, 19 December 2007

2007-12-19T15:15:56Z

Show changes

Aaron: /* Register Map */

2007-12-11T17:53:40Z

← Older revision		Revision as of 19:53, 11 December 2007
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	\|W		\|W
	\|Data FIFO (see FIFO commands, below)		\|Data FIFO (see FIFO commands, below)
			\|-
			\|$0F0
			\|R
			\|Current horizontal video beam position; used by invasn for reading the lightgun (low 11 bits)
	\|-		\|-
	\|$0F2		\|$0F2
	\|R		\|R
	\|~~Looped on until it returns a stable value~~; ~~must change frequently; PRNG? current video line?~~		\|Current vertical video beam position; used by invasn for reading the lightgun (low 10 bits)
	\|-		\|-
	\|$0F4		\|$0F4

Aaron: /* Register Map */

2007-12-11T08:58:23Z

← Older revision		Revision as of 10:58, 11 December 2007
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	\|$004		\|$004
	\|W		\|W
	\|invasn writes via model command $19. Values seen = $00001C00		\|This is a bitmask controlling some texture behaviors:
			:$000000C0 = scale factor for V coordinates (V is specified as V / (1 << ((reg[4] >> 6) & 3)))
			:$00000030 = scale factor for U coordinates (U is specified as U / (1 << ((reg[4] >> 4) & 3)))
			invasn writes via model command $19. Values seen = $00001C00
	\|-		\|-
	\|$006		\|$006

Aaron: /* Model Commands */

2007-12-11T07:12:48Z

Model Commands

← Older revision		Revision as of 09:12, 11 December 2007
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	\|$25/$30		\|$25/$30
	\|7		\|7
	\|<code>$~~30aaaaaa~~ $~~bbbbbbbb~~<br/>		\|<code>$30aabbcc $ddeeffff<br/>
	$~~ccccdddd~~ $~~eeffgggg~~<br/>		$gggghhhh $iijjkkkk<br/>
	$~~hhhhiiii~~ $~~jjkkllll~~<br/>		$llllmmmm $nnoopppp<br/>
	$~~mmmmnnnn~~ $~~ooppqqqq~~<br/>		$qqqqrrrr $ssttuuuu<br/>
	$~~rrrrssss~~ $~~ttuuvvvv~~<br/>		$vvvvwwww $xxyyzzzz<br/>
	$~~wwwwwwww~~ $~~xxxxxxxx~~<br/>		$AAAAAAAA $BBBBBBBB<br/>
	$~~yyyyyyyy~~ $~~zzzzzzzz~~<br/>		$CCCCCCCC $DDDDDDDD<br/>
	</code>		</code>
	\|Specify a quad for rendering. ~~It is unknown what~~ (a) is, but it is ~~sometimes written as $808080, which looks like an RGB scale factor of some sort~~.		\|Specify a quad for rendering. (a b c) is a 1.0.7 unit vector for the polygon normal. Note that in some cases this isn't properly normalized, but I suspect lighting is disabled when this is the case.

	(b) ~~controls~~ texturing. ~~The top byte~~ is usually either $21 or $23; it is unknown what this means. ~~Bit 23~~ is sometimes set to one; its purpose is ~~likewaise~~ unknown. ~~Bit 16~~, when set, means that color 0 in the texture data is transparent. The ~~low~~ 16 bits are a texture V offset. In most quads, the smallest V is normalized to 0 and this is an offset. MK4 uses it as a true offset, specifying a base texture address in the $67 command. Invasion uses this as the full offset, using the $13 command which does not specify a base texture address. In this case, assuming the base == 0 seems to work.		(d) (e) and (f) control texturing. (d) is usually either $21 or $23; it is unknown what this means. The high bit of (e) is sometimes set to one; its purpose is likewise unknown. The low bit of (e), when set, means that color 0 in the texture data is transparent. The 16 bits in (f) are a texture V offset. In most quads, the smallest V is normalized to 0 and this is an offset. MK4 uses it as a true offset, specifying a base texture address in the $67 command. Invasion uses this as the full offset, using the $13 command which does not specify a base texture address. In this case, assuming the base == 0 seems to work.

	(c,d,g) represents the X,Y,Z of the first vertex, in 1.13.2 format. (Note that 1.13.2 × 1.1.14 (matrix value) gives 1.14.16 which can be directly added to the 1.15.16 translation vector.) The texture coordinates of the first vertex are specified by (e,f). This pattern is repeated for the remaining 3 vertices. Vertex 2's X,Y,Z come from (h,i,l), and texture coordinates from (j,k). Vertex 3's X,Y,Z come from (m,n,q) and texture coordinates from (o,p). Vertex 4's X,Y,Z come from (r,s,v) and texture coordinates from (t,u).		(g,h,k) represents the X,Y,Z of the first vertex, in 1.13.2 format. (Note that 1.13.2 × 1.1.14 (matrix value) gives 1.14.16 which can be directly added to the 1.15.16 translation vector.) The texture coordinates of the first vertex are specified by (i,j). This pattern is repeated for the remaining 3 vertices. Vertex 2's X,Y,Z come from (l,m,p), and texture coordinates from (n,o). Vertex 3's X,Y,Z come from (q,r,u) and texture coordinates from (s,t). Vertex 4's X,Y,Z come from (v,w,z) and texture coordinates from (x,y).

	~~It is unknown what w, x, y, and z represent, exactly. Each value corresponds to one of the 4 quad vertices. That is,~~ (w) ~~corresponds to the first vertex~~ (~~c,d,g~~)~~, while~~ (x) ~~corresponds to the second vertex~~ (~~h,i,l~~)~~, etc~~. ~~The values written for billboard~~-~~style quads are generally all equal to $30000000. At other times, the~~ value ~~$300C0300 has been seen, which looks like 3~~ 10-bit values ~~packed together (assuming each is $300 and the~~ top two bits ~~are not used)~~. ~~What could this be for?~~		The final four values (A) (B) (C) and (D) are packed vertex normals for each vertex. Each 32-bit value contains three 10-bit packed values in 1.1.8 format. The top two bits appear to be unused.

	An interesting note here is that this command intersects the FIFO command $25/$30 perfectly. That is, MK4 uses $25 in the FIFO and $25 in the model data. Invasion uses $30 in the FIFO and $30 in the model data. This bolsters the case that the commands are related.		An interesting note here is that this command intersects the FIFO command $25/$30 perfectly. That is, MK4 uses $25 in the FIFO and $25 in the model data. Invasion uses $30 in the FIFO and $30 in the model data. This bolsters the case that the commands are related.