BuLWiP - a TI/99 4/A emulator in C w/SDL2

• Features 9918A video and 9919 sound chip emulation.
• Lower memory usage, less lookup tables, keep important data in cache
• Instruction opcode decoding using CLZ instead of a lookup table
• Memory is designated as 16-bit words as seen from the CPU; no need for builtin_bswap16
• Memory accesses use a function pointer per 256 bytes
• Instruction loop is in a single function; keeping PC, WP, (maybe ST) in host CPU registers
• Instruction decoding functions inlined; better branch prediction

Requirements

• GCC or compatible compiler
• SDL2 library and headers
• ROM and GROM files: 994arom.bin, 994agrom.bin.
  • Put these in the same directory as the emulator executable for dynamic loading.
    • (If you want to have a ROM source listing, it should be named 994arom.lst.)
  • Use make cbulwip for a build with the ROMs compiled in.

Building BuLWiP

• Enter the project folder and run make.
• To build a macOS application bundle:
  • Place 994arom.bin and 994agrom.bin in the bulwip source folder.
  • Use make app to build the .icns and executable and bundle them with the ROM files.
  • Use make capp to build the app with the ROMs compiled into the binary.

Keyboard usage

Key(s)	Description
ESC	Load Cartridges/Settings/Quit menu
F11	Toggle full-screen
F12 or Ctrl-Home	Toggle debugger interface
Ctrl-F12	Reset and reload current cartridge/listings
Shift-Insert	Paste from clipboard
Arrow keys and Tab	Mapped to Joystick 1

Loading Cartridges

• Files ending in G.BIN are assumed to be GROM, otherwise ROM.
• ROM files must be non-inverted (first bank is 0) format.
• Listing file is loaded automatically and must be named the same as the ROM with a .LST extension.
• Cartridge files may be loaded by drag-and-drop onto the window.

While debugger is open

Key(s)	Description
F1	Run/Stop
F2	Single instruction step
Ctrl-F2	Single frame step
Up/Down/PgUp/PgDn	move highlighted line in listing
Home/End	Go to start/end of listing
Ctrl-F	Find text string
Ctrl-G	Repeat last find
Shift-Ctrl-G	Repeat last find, reverse direction
B	Toggle breakpoint at current line (red=stop, green=go)
Del	Remove breakpoint at current line
F5	List breakpoints - Enter: Go to selected breakpoint - Space: Toggle selected breakpoint - Del: Remove selected breakpoint
R	Register select, then Enter to jump to address
Z	Reverse instruction step
Shift-Z	Reverse instruction step until PC goes lower (good for rewinding out of a loop)
1/2/3/S	Show character pattern tables, or sprite pattern table

TODO

• Ctrl->B : Go to referenced label
• SAMS banking 1MB

TODO

• F18A support (some bits work)
• FinalGROM99 cartridge emulation (paged 4Krom+4Kram, gram, load, dump)
• Memory view:
  • A: set address
  • M: CPU memory
  • V: VDP memory
  • G: GROM
  • S: SAMS

Android?

• See cnlohr/rawdrawandroid