SH2 Assembly programming for the Saturn

The Saturn was the successor to the 32X/Genesis

Performance wise it's comparable to the Playstation, While it has some limited 3D capabilities (where it lagged behind the playstation) , it's real strength is 2D games, where it can create arcade quality performance

Cpu	Dual SH2 (28mhz)
Ram	4MB Ram
Video	Dual VDP
Resolution	320x224 / 704/224

Saturn Memory Map

All these can also be accessed through Cache Through addresses at $20000000

Address	Purpose	Details
0x00000000	Boot ROM	Repeats every 512 kb
0x00100000	SMPC registers
0x00180000	Backup RAM
0x00200000	Work RAM Low
0x00300000	Random data	Random on every read (mostly 0x00)
0x00400000	Zero	Always returns 0x0000
0x00800000	Unknown	Always returns 0x00000001000200030004000500060007
0x01000000	Master Init (MINIT)	Data written goes to Master SH-2 Free Running Timer. Section is Write Only.
0x01800000	Slave Init (SINIT)	Data written goes to Slave SH-2 Free Running Timer. Section is Write Only.
0x02000000	CS0	Cartridge 0
0x04000000	CS1	Cartridge 1
0x05000000	Dummy
0x05800000	CD-ROM registers (CS2)	Repeats every 64 Bytes
0x05900000	Unknown	It will lockup the saturn when read
0x05A00000	68000 Audio Work RAM	Stores audio data that will be played
0x05B00000	SCSP registers
0x05C00000	VDP1 VRAM	Video RAM for the 3D/Sprite VDP1
0x05C80000	VDP1 Framebuffer	Current Image Buffer for the VDP1 to render to
0x05D00000	VDP1 Registers	VDP1 variables that change the functionality of how the VDP1 operates
0x05D80000	Lockup when read
0x05E00000	VDP2 VRAM	Video Display Processor 2 (Background) Video RAM - Repeats every 512 kb
0x05F00000	VDP2 CRAM	VDP2 Color RAM - Basically the background Palette - Repeats every 4kb
0x05F80000	VDP2 registers	VDP2 variables that change the functionality of how the VDP2 operates - Repeats every 512 bytes
0x05FC0000	Unknown	Always returns 0x000E0000
0x05FE0000	SCU registers	Repeats every 256 bytes
0x05FF0000	Unknown registers	Repeats every 256 bytes
0x06000000	Work RAM High

VDP1

Name	Address	Purpose	Bits	Details
TVHR	$25D00000	TV mode selection (W)	%------------VTTT	V=Vblank erase / T=Tv mode
FBCR	$25D00002	Frame buffer change mode (W)	%-----------EddFf
PTMR	$25D00004	Draw trigger (W)	%--------------PP	Plot trigger (0/1/2=Idle/Start/StartOnFrameChange)
EWDR	$25D00006	Erase/write data (W)	%EEEEEEEEeeeeeeee
EWLR	$25D00008	Erase/write upper-left coordinate (W)	%-XXXXXXYYYYYYYYY
EWRR	$25D0000A	Erase/write lower-right coordinate (W)	%XXXXXXXYYYYYYYYY
ENDR	$25D0000C	Draw forced termination (W)	%----------------
EDSR	$25D00010	Transfer end status (R)	%--------------CB	C=1=Fetched an ended / B=1=Fetched before end
LOPR	$25D00012	Last operation command address (R)	%AAAAAAAAAAAAAA00	Address / 8h
COPR	$25D00014	Current operation command address (R)	%AAAAAAAAAAAAAA00	Address / 8h
MODR	$25D00016	Mode status (R)	%VVVV---PEDdFvTTT	V=Version / P=plot trigger E=even coord / D=double interlace enable/ d=double interlace draw / F=Frame buffer change mode / v=vblank erase/write enable / T=tvmode selection

VDP2

Name	Address	Purpose	Bits	Details
TVMD	$25F80000	TV Screen Mode (Read Allowed)	%D------BLLVV-HHH	D=1=Screen on B=1=Blackout L=interlace H=Hres V=Vres
EXTERN	$25F80002	External Signal Enable Register	%------LS------sG
TV STAT	$25F80004	Screen Status (Read Only)	%------LS----VHOP
VRSIZE	$25F80006	VRAM size (Read Allowed)	%V-----------vvvv
HCNT	$25F80008	H-Counter (Read Only)	%------HHHHHHHHHH
VCNT	$25F8000A	V-Counter (Read Only)	%------VVVVVVVVVV
	$25F8000C	Reserved
RAMCTL	$25F8000E	Ram Control (Read Allowed)	%C-cc--VVRRRRRRRR	C=CRKTE c=CRMD V=VRBMD R=RDBS
CLCA0L	$25F80010	Vram Cycle Pattern (Bank A0)	%VVVVVVVVVVVVVVVV
CYCA0U	$25F80012	Vram Cycle Pattern (Bank A0)	%VVVVVVVVVVVVVVVV
CLCA1L	$25F80014	Vram Cycle Pattern (Bank A1)	%VVVVVVVVVVVVVVVV
CYCA1U	$25F80016	Vram Cycle Pattern (Bank A1)	%VVVVVVVVVVVVVVVV
CLCB0L	$25F80018	Vram Cycle Pattern (Bank B0)	%VVVVVVVVVVVVVVVV
CYCB0U	$25F8001A	Vram Cycle Pattern (Bank B0)	%VVVVVVVVVVVVVVVV
CLCB1L	$25F8001C	Vram Cycle Pattern (Bank B1)	%VVVVVVVVVVVVVVVV
CYCB1U	$25F8001E	Vram Cycle Pattern (Bank B1)	%VVVVVVVVVVVVVVVV
BGON	$25F80020	Screen Display Enable	%---RNNNN--rrnnnn	RN=Transparency / rn=enabled
MZCTL	$25F80022	Mosaic Control	%MMMMMMMM---RNNNN
SFSEL	$25F80024	Special Function Code Select	%-----------RNNNN
SFCODE	$25F80026	Special Function Code	%SSSSSSSSSSSSSSSS
CHCTLA	$25F80028	Character Control (NBG0, NBG1)	%--CCNNES-cccnnes	c=colors (16/256/2k/32k/16m) e=1=bmp format nn=bmp size (512x256/512x512/ 1024x256/1024x512)
CHCTLB	$25F8002A	Character Control (NBG2, NBG3,RBG0)	%-RRR-rrr--NN--nn
BMPNA	$25F8002C	Bitmap Palette Number (NBG0, NBG1)	%--NN-nnn--NN--nn
BMPNB	$25F8002E	Bitmap Palette Number (RGB0)	%----------NN--nn
PNCN0	$25F80030	Pattern Name Control (NBG0)	%NN----NNNNNNNNNN
PNCN1	$25F80032	Pattern Name Control (NBG1)	%NN----NNNNNNNNNN
PNCN2	$25F80034	Pattern Name Control (NBG2)	%NN----NNNNNNNNNN
PNCN3	$25F80036	Pattern Name Control (NBG3)	%NN----NNNNNNNNNN
PNCR	$25F80038	Pattern Name Control (RBG0)	%NN----NNNNNNNNNN
PLSZ	$25F8003A	Plane Size	%RRRRRRRRNNNNNNNN
MPOFN	$25F8003C	Map Offset (NBG0-NBG3)	%-NNN-nnn-NNN-nnn
MPOFR	$25F8003E	Map Offset (Rotation Parameter A,B)	%---------BBB-AAA
MPABN0	$25F80040	MAP (NBG0 Plane A,B)	%--NNNNNN--nnnnnn
MPCDN0	$25F80042	MAP (NBG0 Plane C,D)	%--NNNNNN--nnnnnn
MPABN1	$25F80044	MAP (NBG1 Plane A,B)	%--NNNNNN--nnnnnn
MPCDN1	$25F80046	MAP (NBG1 Plane C,D)	%--NNNNNN--nnnnnn
MPABN2	$25F80048	MAP (NBG2 Plane A,B)	%--NNNNNN--nnnnnn
MPCDN2	$25F8004A	MAP (NBG2 Plane C,D)	%--NNNNNN--nnnnnn
MPABN3	$25F8004C	MAP (NBG3 Plane A,B)	%--NNNNNN--nnnnnn
MPCDN3	$25F8004E	MAP (NBG3 Plane C,D)	%--NNNNNN--nnnnnn
MPABRA	$25F80050	MAP (Rotation Parameter A Plane A,B)	%--RRRRRR--rrrrrr
MPCDRA	$25F80052	MAP (Rotation Parameter A Plane C,D)	%--RRRRRR--rrrrrr
MPEFRA	$25F80054	MAP (Rotation Parameter A Plane E,F)	%--RRRRRR--rrrrrr
MPGHRA	$25F80056	MAP (Rotation Parameter A Plane G,H)	%--RRRRRR--rrrrrr
MPIJRA	$25F80058	MAP (Rotation Parameter A Plane I,J)	%--RRRRRR--rrrrrr
MPKLRA	$25F8005A	MAP (Rotation Parameter A Plane K,L)	%--RRRRRR--rrrrrr
MPMNRA	$25F8005C	MAP (Rotation Parameter A Plane M,N)	%--RRRRRR--rrrrrr
MPOPRA	$25F8005E	MAP (Rotation Parameter A Plane O,P)	%--RRRRRR--rrrrrr
MPABRB	$25F80060	MAP (Rotation Parameter B Plane A,B)	%--RRRRRR--rrrrrr
MPCDRB	$25F80062	MAP (Rotation Parameter B Plane C,D)	%--RRRRRR--rrrrrr
MPEFRB	$25F80064	MAP (Rotation Parameter B Plane E,F)	%--RRRRRR--rrrrrr
MPGHRB	$25F80066	MAP (Rotation Parameter B Plane G,H)	%--RRRRRR--rrrrrr
MPIJRB	$25F80068	MAP (Rotation Parameter B Plane I,J)	%--RRRRRR--rrrrrr
MPKLRB	$25F8006A	MAP (Rotation Parameter B Plane K,L)	%--RRRRRR--rrrrrr
MPMNRB	$25F8006C	MAP (Rotation Parameter B Plane M,N)	%--RRRRRR--rrrrrr
MPOPRB	$25F8006E	MAP (Rotation Parameter B Plane O,P)	%--RRRRRR--rrrrrr
SCXIN0	$25F80070	Screen Scroll Value (NBG0, Horizontal Integer Part)	%-----NNNNNNNNNNN
SCXDN0	$25F80072	Screen Scroll Value (NBG0, Horizontal Fractional Part)	%NNNNNNNN--------
SCYIN0	$25F80074	Screen Scroll Value (NBG0, Vertical Integer Part)	%-----NNNNNNNNNNN
SCYDN0	$25F80076	Screen Scroll Value (NBG0, Vertical Fractional Part)	%NNNNNNNN--------
ZMXIN0	$25F80078	Coordinate Increment (NBG0, Horizontal Integer Part)	%-------------NNN
ZMXDN0	$25F8007A	Coordinate Increment (NBG0, Horizontal Fractional Part)	%NNNNNNNN--------
ZMYIN0	$25F8007C	Coordinate Increment (NBG0, Vertical Integer Part)	%-------------NNN
ZMYDN0	$25F8007E	Coordinate Increment (NBG0, Vertical Fractional Part)	%NNNNNNNN--------
SCXIN1	$25F80080	Screen Scroll Value (NBG1, Horizontal Integer Part)	%-----NNNNNNNNNNN
SCXDN1	$25F80082	Screen Scroll Value (NBG1, Horizontal Fractional Part)	%NNNNNNNN--------
SCYIN1	$25F80084	Screen Scroll Value (NBG1, Vertical Integer Part)	%-----NNNNNNNNNNN
SCYDN1	$25F80086	Screen Scroll Value (NBG1, Vertical Fractional Part)	%NNNNNNNN--------
ZMXIN1	$25F80088	Coordinate Increment (NBG1, Horizontal Integer Part)	%-------------NNN
ZMXDN1	$25F8008A	Coordinate Increment (NBG1, Horizontal Fractional Part)	%NNNNNNNN--------
ZMYIN1	$25F8008C	Coordinate Increment (NBG1, Vertical Integer Part)	%-------------NNN
ZMYDN1	$25F8008E	Coordinate Increment (NBG1, Vertical Fractional Part)	%NNNNNNNN--------
SCXN2	$25F80090	Screen Scroll Value (NBG2, Horizontal)	%-----NNNNNNNNNNN
SCYN2	$25F80092	Screen Scroll Value (NBG2, Vertical	%-----NNNNNNNNNNN
SCXN3	$25F80094	Screen Scroll Value (NBG3, Horizontal)	%-----NNNNNNNNNNN
SCYN3	$25F80096	Screen Scroll Value (NBG3, Vertical	%-----NNNNNNNNNNN
ZNCTL	$25F80098	reduction enable register	%------NN------nn
SCRCTL	$25F8009A	Line and Vertical Cell Scroll Control (NBG0,NBG1)	%--NNNNNN--nnnnnn
VCSTAU	$25F8009C	Vertical Cell Scroll Table Address (NBG0,NBG1)	%-------------VVV
VCSTAL	$25F8009E	Vertical Cell Scroll Table Address (NBG0,NBG1)	%VVVVVVVVVVVVVVV-
LSTA0U	$25F800A0	Line Scroll Table Address (NBG0)	%-------------NNN
LSTA0L	$25F800A2	Line Scroll Table Address (NBG0)	%NNNNNNNNNNNNNNN-
LSTA1U	$25F800A4	Line Scroll Table Address (NBG1)	%-------------NNN
LSTA1L	$25F800A6	Line Scroll Table Address (NBG1)	%NNNNNNNNNNNNNNN-
LCTAU	$25F800A8	Line Color Screen Table Address	%-------------VVV
LCTAL	$25F800AA	Line Color Screen Table Address	%VVVVVVVVVVVVVVV-
BKTAU	$25F800AC	Back Screen Table Address	^B------------bbb
BKTAL	$25F800AE	Back Screen Table Address	%BBBBBBBBBBBBBBBB
RPMD	$25F800B0	Rotation Parameter Mode	%--------------RR
RPRCTL	$25F800B2	Rotation Parameter Read Control	%-----RRR-----rrr
KTCTL	$25F800B4	Coefficient Table Control	%---RRRRR---rrrrr
KTAOF	$25F800B6	Coefficient Table Address Offset (Rotation Parameter A,B)	%-----RRR-----rrr
OVPNRA	$25F800B8	Screen Over Pattern Name (Rotation Parameter A)	%RRRRRRRRRRRRRRRR
OVPNRB	$25F800BA	Screen Over Pattern Name (Rotation Parameter B)	%RRRRRRRRRRRRRRRR
RPTAU	$25F800BC	Rotation Parameter Table Address (Rotation Parameter A,B)	%-------------RRR
RPTAL	$25F800BE	Rotation Parameter Table Address (Rotation Parameter A,B)	%RRRRRRRRRRRRRRR-
WPSX0	$25F800C0	Windows Position (W0, Horizontal Start Point)	%------WWWWWWWWWW
WPSY0	$25F800C2	Windows Position (W0, Vertical Start Point)	%-------WWWWWWWWW
WPEX0	$25F800C4	Windows Position (W0, Horizontal End Point)	%------WWWWWWWWWW
WPEY0	$25F800C6	Windows Position (W0, Vertical End Point)	%-------WWWWWWWWW
WPSX1	$25F800C8	Windows Position (W1, Horizontal Start Point)	%------WWWWWWWWWW
WPSY1	$25F800CA	Windows Position (W1, Vertical Start Point)	%-------WWWWWWWWW
WPEX1	$25F800CC	Windows Position (W1, Horizontal End Point)	%------WWWWWWWWWW
WPEY1	$25F800CE	Windows Position (W1, Vertical End Point)	%-------WWWWWWWWW
WCTLA	$25F800D0	Window Control (NBG0, NBG1)	%N-nnnnnnN-nnnnnn
WCTLB	$25F800D2	Window Control (NBG2, NBG3)	%N-nnnnnnN-nnnnnn
WCTLC	$25F800D4	Window Control (RGB0, Sprite)	%S-ssssssR-rrrrrr
WCTLD	$25F800D6	Window Control (Parameter Window, Color Calc. Window)	%C-ccccccR---rrrr
LWTA0U	$25F800D8	Line Window Table Address (W0)	%W------------www
LWTA0L	$25F800DA	Line Window Table Address (W0)	%WWWWWWWWWWWWWWW-
LWTA1U	$25F800DC	Line Window Table Address (W1)	%W------------www
LWTA1L	$25F800DE	Line Window Table Address (W0)	%WWWWWWWWWWWWWWW-
SPCTL	$25F800E0	Sprite Control	%--ss-SSS--ssssss
SDCTL	$25F800E2	Shadow Control	%-------T--BRNNNN
CRAOFA	$25F800E4	Color Ram Address offset (NBG0-NBG3)	%-nnn-NNN-nnn-NNN
CRAOFB	$25F800E6	Color Ram Address offset (RBG0, Sprite)	%---------SSS-RRR
LNCLEN	$25F800E8	Line Color Screen Enable	%----------SRNNNN
SFPRMD	$25F800EA	Special Priority Mode	%------RRNNNNNNNN
CCCTL	$25F800EC	Color Calculation Control	%BBBB-ECC-SLRNNNN
SFCCMD	$25F800EE	Special Color Calculation Mode	%------RRNNNNNNNN
PRISA	$25F800F0	Priority Number (Sprite 0,1)	%-----sss-----SSS
PRISB	$25F800F2	Priority Number (Sprite 2,3)	%-----sss-----SSS
PRISC	$25F800F4	Priority Number (Sprite 4,5)	%-----sss-----SSS
PRISD	$25F800F6	Priority Number (Sprite 6,7)	%-----sss-----SSS
PRINA	$25F800F8	Priority Number (NBG0,NBG1)	%-----NNN-----nnn
PRINB	$25F800FA	Priority Number (NBG2,NBG3)	%-----NNN-----nnn
PRIR	$25F800FC	Priority Number (RBG0)	%-------------nnn
	$25F800FE	Reserved
CCRSA	$25F80100	Color Calculation Ration (Sprite 0,1)	%---sssss---SSSSS
CCRSB	$25F80102	Color Calculation Ration (Sprite 2,3)	%---sssss---SSSSS
CCRSC	$25F80104	Color Calculation Ration (Sprite 4,5)	%---sssss---SSSSS
CCRSD	$25F80106	Color Calculation Ration (Sprite 6,7)	%---sssss---SSSSS
CCRNA	$25F80108	Color Calculation Ration (NBG0,NBG1)	%---NNNNN---nnnnn
CCRNB	$25F8010A	Color Calculation Ration (NBG2,NBG3)	%---NNNNN---nnnnn
CCRR	$25F8010C	Color Calculation Ration (TBG0)	%-----------RRRRR
CCRLB	$25F8010E	Color Calculation Ration (Line Color Screen, Back Screen)	%---BBBBB---LLLLL
CLOFEN	$25F80110	Color Offset Enable	%---------SBRNNNN
CLOFSL	$25F80112	Color Offset Select	%---------SBRNNNN
COAR	$25F80114	Color Offset A (Red)	%-------CCCCCCCCC
COAG	$25F80116	Color Offset A (Green)	%-------CCCCCCCCC
COAB	$25F80118	Color Offset A (Blue)	%-------CCCCCCCCC
COBR	$25F8011A	Color Offset B (Red)	%-------CCCCCCCCC
COBG	$25F8011C	Color Offset B (Green)	%-------CCCCCCCCC
COBB	$25F8011E	Color Offset B (Blue)	%-------CCCCCCCCC

SMPC System Manager & Peripheral control

See: ST-169-R1-072694 System Manager & Peripheral control PG 21+

Name	Address	Purpose
IREG0	$20100001	Input Register
IREG1	$20100003	Input Register
IREG2	$20100005	Input Register
IREG3	$20100007	Input Register
IREG4	$20100009	Input Register
IREG5	$2010000B	Input Register
IREG6	$2010000D	Input Register
COMREG	$2010001F	Command Register
OREG0	$20100021	Output Register
OREG1	$20100023	Output Register
OREG2	$20100025	Output Register
OREG3	$20100027	Output Register
OREG4	$20100029	Output Register
OREG5	$2010002B	Output Register
OREG6	$2010002D	Output Register
OREG7	$2010002F	Output Register
OREG8	$20100031	Output Register
OREG9	$20100033	Output Register
OREG10	$20100035	Output Register
OREG11	$20100037	Output Register
OREG12	$20100039	Output Register
OREG13	$2010003B	Output Register
OREG14	$2010003D	Output Register
OREG15	$2010003F	Output Register
OREG16	$20100041	Output Register
OREG17	$20100043	Output Register
OREG18	$20100045	Output Register
OREG19	$20100047	Output Register
OREG20	$20100049	Output Register
OREG21	$2010004B	Output Register
OREG22	$2010004D	Output Register
OREG23	$2010004F	Output Register
OREG24	$20100051	Output Register
OREG25	$20100053	Output Register
OREG26	$20100055	Output Register
OREG27	$20100057	Output Register
OREG28	$20100059	Output Register
OREG29	$2010005B	Output Register
OREG30	$2010005D	Output Register
OREG31	$2010005F	Output Register
SR	$20100061	Status Register
SF	$20100063	Status Flag
PDR1	$20100075	Port Dat register 1
PDR2	$20100077	Port Dat register 2
DDR1	$20100079	Data Direction Register 1
DDR2	$2010007B	Data Direction Register 2
IOSEL	$2010007D	IO Select
EXLE	$2010007F	External Latch Enable