Game Boy Classic fully functional FPGA implementation from scratch
###Requirements
sudo apt-get install iverilog gtkwave
##Compiling code
cd sim/
make compile
##Running a simulation
cd sim/
make run
Once the simulation completes, the following ASCII files are generated under the sim/ folder:
- pgb_cpu.log : Z80 macro instructions and their corresponding micro-code flows
- pgb_gpu.log: GPU micro code dump
- generated_frames/*.ppm : PPM representation of the video buffer frames at the time the simulation ended. (Open it with gimp)
- papi_vram_8000_8fff.dump : Memory dump for the Tile set region 0
- papi_vram_9800_9bff.dump : Memory dump for the Tile map region 0
- tb_simple_dzcpu : Simulation testbench executable
Simulations will not automatically generate a VCD dump file. To generate a VCD dump do:
make DUMPTYPE=vcd
##Simulation Options To control additional simulation options, use the SIMFLAGS flag. Valid values are:
-DSTOP_AFTER_FIRST_FRAME: The simulation will stop once the first frame has been generated under the sim/generated_frames/ folder-DENABLE_CPU_LOG: Enables pgb_cpu.log generation (enabled by default)-DENABLE_GPU_LOG: Enables pgb_cpu.log generation (enabled by default)-DCARTRIGDE_DUMP_PATH: When LOAD_CARTRIDGE_FROM_FILE is set, then this flag specifies the path to the dump file-DSKIP_BIOS: Skips the BIOS code, first 256 instructions, effectively jumping directly to 0x100-DDISABLE_CPU: Disables the CPU from running-DVMEM_DUMP_PATH: When LOAD_VMEM_DUMP is set, then this flag specifies the path to the VMEME dump file.-DSIMULATION_TIME_OUT: Specify a simulation timeout in nanoseconds Example:
The following command will stop the simulation after the first frame, will generate GPU log, but will not generate CPU log.
make SIMFLAGS="-DSTOP_AFTER_FIRST_FRAME -DENABLE_GPU_LOG"
The following command will simulate RTL using a cartrigde file:
make SIMFLAGS=" -DCARTRIGDE_DUMP_PATH='\"resources/tetris.dump\"'"
The following command will disable the CPU and load VMEM data from a dump file:
make SIMFLAGS="-DDISABLE_CPU -DVMEM_DUMP_PATH='\"resources/tetris_vmem_8000_9fff.dump\"' -DENABLE_GPU_LOG -DSTOP_AFTER_FIRST_FRAME"
##Looking at simulation results
cd sim/
make view
##Cleaning up simulation files. This also erases the vcd and the log files!
make clean
##Installing a game boy assembly
RGBDS is a great gameboy assembly (https://www.anjbe.name/rgbds/)
To install it do:
git clone https://github.com/bentley/rgbds/
cd rgbds
sudo apt-get install bison flex
make
sudo make install
To compile an assebly program called test_INCr_b.asm do:
rgbasm -o test_INCr_b.obj test_INCr_b.asm
rgblink -m test_INCr_b.map -n test_INCr_b.sym -o test_INCr_b.gb test_INCr_b.obj
The use hexdump to get the ASCII hex dump to load into the RTL simulation:
hexdump -v test_INCr_b.gb > test_INCr_b.hex