Realization of a RedCore to Bytecode compiler and a Virtual Machine interpreting and executing .cor files (Bytecode)
The Corewar is a project at the end of the first year at Epitech. The project is divided into two parts for a group of 3 to 4 people. Each group in the promotion competes to have the best Corewar.
We have 2 bonuses, the first a viewer of the arena in the VM (interactive), then in the second bonus, a program which makes several champions compete several times in order to create a ranking of the best champions.
In the virtual machine, champions compete in a circular 6144 bytes arena. Each champion's instruction are executed at the end of their cycle. The champions all compete in the same arena and their execution follows a scheduling.
All champions are written in RedCode (.s (Assembly) compiled in Bytecode (.cor) thanks to the ASM part of the project. Only bytecode generated by the ASM part can be executed by the Virtual Machine (VM).
Each process (champions) has :
- a Live : value denoting whether a process is alive or not.
- a PC : Special register which designates the head of the champion and the command to be executed in the next cycle.
- a Carry : A flag indicating whether a command succeeded or not.
- 16 Registers : Each register is 4 bytes.
On initialization, all registers, carry and live are initialized to 0 execpt the first register which is the player number and the PC which is the position of the first instruction of the process in the arena.
- The winner is the last process said to be alive (Live).
- Every CYCLE_TO_DIE, the VM checks that each process is alive (Live). If the Live of a process is 0 (dead), it is destroyed.
- Every NBR_LIVE, the CYCLE_TO_DIE is decremented by CYCLE_DELTA so that the game does not last indefinitely.
| Mnemonic | Description |
|---|---|
| 0x01 (live) | Takes 1 parameter: 4 bytes that represent the player's number. It indicates that the player is alive. |
| 0x02 (ld) | Takes 2 parameters. It loads the value of the first parameter into the second parameter, which must be register (not a PC). This operation modifies the Carry. ld 34,r3 loads the REG_SIZE bytes starting at the address PC + 34 % IDX_MOD into r3. |
| 0x03 (st) | Takes 2 parameters. It stores the first parameter's value (which is a register) into the second (whether a register or a number). st r4,34 stores the content of r4 at the address PC + 34 % IDX_MOD. st r3,r8 copies the content of r3 into r8. |
| 0x04 (add) | Takes 3 parameters. It adds the content of the first two and puts the sum into the third one (which must be a register). This operation modifies the carry. add r2,r3,r5 adds the content of r2 and r3 and puts the result into r5. |
| 0x05 (sub) | Similar to and, but performing a substraction. |
| 0x06 (and) | Takes 3 parameters. It performs a binary AND between the first two parameters and stores the result into the third one (which be a register). This operation modifies the carry. and r2,%0,r3 puts r2 & 0 into r3. |
| 0x07 (or) | Similar to and, but performing a binary OR. |
| 0x08 (xor) | Similar to and, but performing a binary XOR (exclusive OR). |
| 0x09 (zjump) | Takes 1 parameter, which must be index. It jumps to the index if the carry is worth 1. Otherwise, it does nothing but consumes the same time. zjump %23 puts, if carry equals 1, PC + 23 % IDX_MOD into the PC. |
| 0x0a (ldi) | Takes 3 parameters. The first two must be indexes, the third one must be a register. This operation modifies the carry. ldi 3,%4,r1 reads IND_SIZE bytes from the address PC + 3 % IDX_MOD, adds 4 to this value. The sum is named S. REG_SIZE bytes are read from the address PC + S % IDX_MOD and copied into r1. |
| 0x0b (sti) | Takes 3 parameters. The first one must be a register. The other two can be indexes or registers. sti r2,%4,r5 copies the content of r2 into the address PC + (4+5) % IDX_MOD. |
| 0x0c (fork) | Takes 1 parameter, which must be an index. It create a new program that inherits different states from the parent. This program is executed at the address PC + first parameter % IDX_MOD. |
| 0x0d (lld) | Similar to ldi without the % IDX_MOD. This operation modifies the carry. |
| 0x0e (lldi) | Similar to ldi without the % IDX_MOD. This operation modifies the carry. |
| 0x0f (lfork) | Similar to fork without the % IDX_MOD. |
| 0x10 (aff) | Takes 1 parameter, which must be a register. It displays on the standard output the character whose ASCII code is the content of the register (in base 10). A 256 modulo is applied to this ASCII code. aff r3 displays ’*’ if r3 contains 42. |
The ASM part is about compiling redcode files .s into byte code files .cor and verifying if this code is correct.
You can create your own champions and compile them using this part of the project to use them inside the VM part.
Check_error:
The compiler is checked by the moulinette. Here's a proof of quality:
In redcode, there is some cleaning to do before parsing the code.
First, we got rid of the comments. (begin with a #).
Then, each line should be splitted using the following characters : " ", "\t", ",".
Once it's done, the first line should specify the name of the champion :
.name "[NAME]"And the second one should specify the description of the champion :
.comment "[DESCRIPTION]"After that, each line should be formatted the following way:
[label](command)(arguments)A label should be regarded as a checkpoint. It's marking a position in the code of the champion end it's followed by a :.
The label is always optionnal.
Howerver, the command and it's arguments are mandatory. Each command take specific types of arguments has a parameter, everything is specified in the All Instruction section.
If any of this rules is not followed, the program will not compile and will return 84 as an error status.
Usage:
In order to use the asm part, you have to get into the asm folder. From the root of the repository, execute this command:
cd asmIn order to compile a champion (.s)
./asm champion_file[.s]If you need help, just use the -h option:
./asm -hgit clone git@github.com:Just1truc/Corewar-EPITECH-2022.git
cd Corewar-EPITECH-2022
makeFrom the root of the repository:
./asm/asm [file.s]
./corewar/corewar [file.cor] [file.cor] ...| Description | Mark |
|---|---|
| Header | 3/3 |
| Full header | 5/5 |
| Valid bytecode cases | 18/18 |
| Invalid cases | 35/35 |
| Total | 100% |
| Description | Mark |
|---|---|
| Preliminary | 2/2 |
| Assembler | 10/10 |
| Virtual Machine | 10/10 |
| Total | 22/22 |
The first bonus is a Corewar (VM) interactive viewer.
