emrsmsrli / gameboiadvance Goto Github PK

Implement a full fledged disassembler.

ARM instructions

• Branch and Branch with Link (B, BL, BX, SWI)
• Data Processing (ALU)
• Multiply and Multiply-Accumulate (MUL, MLA)
• PSR Transfer (MRS, MSR)
• Memory: Single Data Transfer (LDR, STR)
• Memory: Halfword, Doubleword, and Signed Data Transfer
• Memory: Block Data Transfer (LDM, STM)
• Memory: Single Data Swap (SWP)
• Coprocessor (MRC/MCR, LDC/STC, CDP, MCRR/MRRC) -- no need since GBA does not have any coprocessors

Thumb instructions

• Register Operations (ALU, BX)
• Memory Load/Store (LDR/STR)
• Memory Addressing (ADD PC/SP)
• Memory Multiple Load/Store (PUSH/POP and LDM/STM)
• Jumps and Calls

Following format should be fine:
[address] | [instruction_dword] - [disassembly]

Implement these registers:

• WAITCNT, dictates the wait states of gamepak accesses
• POSTFLG
• HALTCNT (W only)
• Internal Memory Control (WONT DO)
• Gamepak prefetch mechanism, triggered by WAITCNT.
  https://problemkaputt.de/gbatek.htm#gbagamepakprefetch

the game has a blending issue with the Maxis logo

Implement input controller as follows:

• KEYINPUT reg, status of keys
• KEYCNT reg, irq control

See this GBATEK section.

Rough TODO list:

• Pull metadata from cartridge header
• Search for backup id string in rom
  • Optionally add some backup type database consisting roms with known save types
• Implement backup types
  • SRAM/FRAM
  • EEPROM
  • Flash ROM
• Implement some GPIO functionality. Maybe only RTC?
• Implement erase, write etc timings

• SIO Normal Mode
• SIO Multi-Player Mode
• SIO UART Mode
• SIO JOY BUS Mode
• SIO General-Purpose Mode
• Implement actual connection using sfml network module

Should show the contents of memory within a certain region.
Included regions taken from GBATEK:

General Internal Memory

00000000-00003FFF BIOS - System ROM
00004000-01FFFFFF Not used
02000000-0203FFFF WRAM - On-board Work RAM
02040000-02FFFFFF Not used
03000000-03007FFF WRAM - On-chip Work RAM
03008000-03FFFFFF Not used
04000000-040003FE I/O Register
04000400-04FFFFFF Not used

Internal Display Memory

05000000-050003FF BG/OBJ Palette RAM
05000400-05FFFFFF Not used
06000000-06017FFF VRAM - Video RAM
06018000-06FFFFFF Not used
07000000-070003FF OAM - OBJ Attributes
07000400-07FFFFFF Not used

External Memory (Game Pak)

08000000-09FFFFFF Game Pak ROM/FlashROM (max 32MB)
0A000000-0BFFFFFF Game Pak ROM/FlashROM (max 32MB)
0C000000-0DFFFFFF Game Pak ROM/FlashROM (max 32MB)
0E000000-0E00FFFF Game Pak SRAM

• ewram
• iwram
• io regs
• palette ram
• vram
• oam
• pak rom
• pak backup memory

Should show gamepak metadata info.

• Pak path
• Title
• Game code
• Maker code
• Checksum
• Backup type string

Optionally show memory views of the Pak and the backup medium. Or alternatively they should be shown in memory debugger mentioned in #4

Mother 3 intro shows washed up colors and "press to start" objs are not being shown

game crashes when first game is picked to play

The game shows 4 empty rectangular shapes instead of SEGA logo on start

The game is hanging because of block transfer

Game reads etc without CMD, something must be broken with RTC impl

A list of TONC demos. Won't try to run them all correctly probably:

• bm_modes
• brin_demo
• bm_modes
• brin_demo
• first
• hello
• key_demo
• m3_demo
• pageflip
• sbb_reg
• second
• bigmap
• m7_demo_mb
• obj_aff
• sbb_aff
• tmr_demo
• txt_obj
• dma_demo
• m7_ex
• obj_demo
• snd1_demo
• txt_se1
• bld_demo
• irq_demo
• mos_demo
• octtest
• swi_demo
• tte_demo
• txt_se2
• cbb_demo
• m7_demo
• oacombo
• prio_demo
• swi_vsync
• txt_bm
• win_demo

Game is crashing because of block data transfer cpsr load

Implement a debugger module which shows the current CPU state

• Registers with all modes
• Pipeline state
• Timers
• DMA states
• Disassembly around PC (?)
• Halt state
• Interrupts
• BIOS latch
• Open bus value
• Breakpoints

Game crashes when "Sleep Mode" is selected in the options

This should be one of the hardest aspects of the emulator. Lots of things to do:

• DISPCNT and GREEN SWAP registers
• DISPSTAT and VCOUNT registers
• BG*CNT registers (1-4)
• bg offset registers
• bg rotate scale registers
• window registers
• mosaic
• special color effect regs (alpha blending etc)
• see TIMINGS (render takes 4 cpu cycle per dot)
• bitmap rendering
• normal bg rendering
• affine bg rendering
• obj rendering
• composition
  • blending
  • windowing
  • obj windowing

• input
• irq enabled keys
• irq master enable
• irq condition

implement a stack based vector (or use PMR) for use in hot loops, where variable size container are needed (i.e block data transfer -> generate rlist)

Uno 52 and Uno Free Fall never transitions into main menu

• EEPROM4 is not being detected
• EEPROM is not really working, games report "cannot save" messages

• Registers
• FIFO representation
• Wave ram memory view
• Wave representations

KEYINPUT should be initialized with 0x03FF rather than 0x003F

Implement DMA mechanism https://problemkaputt.de/gbatek.htm#gbadmatransfers

• Prioritize DMA ticks
• Implement special DMA trigger (DMA0=Prohibited, DMA1/DMA2=Sound FIFO, DMA3=Video Capture)

When 3 channels are running simultaneously, the length field of the last one gets corrupted. this generally happens in the case of dma1(fifo) + dma2(fifo) + dma3(imm).

Take Mother 3 for example, it freezes the emulator on title screen, or shortly after the game begins

This issue tracks ARM7TDMI emulation

• ARM instructions
  • DataProc
  • PSR
  • BX
  • Multiply
  • MulLong
  • Trans
  • Undefined
  • BlockTrans
  • B,BL
  • SWI
• Thumb instructions
  • move_shifted_reg
  • add_subtract
  • mov_cmp_add_sub_imm
  • alu
  • hireg_bx
  • pc_rel_load
  • ld_str_reg
  • ld_str_sign_extended_byte_hword
  • ld_str_imm
  • ld_str_hword
  • ld_str_sp_relative
  • ld_addr
  • add_offset_to_sp
  • push_pop
  • ld_str_multiple
  • branch_cond
  • swi_thumb
  • branch
  • long_branch_link
• Timers
• Interrupt handling
• Interrupt delay
• Halt, stop mode

Tracking

• #20
• #21
• #22
• #24
• #25
• #26
• #28
• #29
• #31
• #32
• #33

• Registers
• BG views
  • BG0
  • BG1
  • BG2 (also bitmap view)
  • BG3
• OAM view
• Tile view
• Palette view
• Screen buffer
• Window buffer

Tracking issues:

• Disassembler: #1
• Memory View: #4
• Gamepak: #5
• ARM #13
• Keypad #16
• PPU #17
• APU #23
• SIO

game sometimes runs too slow. should profile while running it

Mostly same with the GB sound. DMA and timers supply 2 channels, should be tricky to do.

• migrate PSG channels from gameboi
• implement DMA sound channels (Channel A&B)
• implement new registers
  https://problemkaputt.de/gbatek.htm#gbasoundcontroller

game immediately crashes after bios