aabmass / very-simple-emulator

An emulator for a very simple CPU with a very simple instruction set. In C++

very-simple-emulator

This emulates a very simple instruction set and can execute a binary rom image directly. Assembler to come.

Building

Make sure you have a C++ compiler and cmake. No other dependencies!

git clone https://github.com/aabmass/very-simple-emulator.git
cd very-simple-emulator
mkdir build
cd build
cmake ..
make

# creates main in build folder

Executing

To run the emulator, write a binary file smileys.bin and pass its path to main. Each opcode is a byte wide (the instruction register gets 8 bits). See the samples in the sample directory, open them in a hex editor or run hexdump etc.

So to run the sample smiley program:

# from the source root with binary built in build directory
./build/main sample-programs/smileys.bin

Output

Currently, main() runs the program passed as its first arg and then prints the state of the virtual machine's registers when it's "done". By done, I mean the pseudo instruction (just for emulation) BRK (opcode 0xFF) is encountered. The sample program smileys.bin prints ten smiley's!

:)
:)
:)
:)
:)
:)
:)
:)
:)
:)

Finished running program! End state of VM:
(PC, IR, A, B, X, Y) = (28, 255, 73, 11, 10, 0)

The values in the registers are in decimal. The outputted smiley's are bytes that std::cout formats as ASCII.