This is a project I've been slowly working on for about half a year now. The goal is to try and build a small (and decently reliable) VM from the ground up, learning more and more C as I go.
Right now there are instructions, registers, a stack, data memory, and the most basic of gotos.
makemake install
NOTE: See carp -h for help with command-line options.
- Write a Carp file - see SYNTAX.md. More formal spec coming.
- Run
carp -f your_file.carp.
- Include
carp/carp.hin your program. - Run
gcc program.c /usr/local/lib/libcarp.a -o program.out.
Defined as such: NAME (args): Description
- HALT (code): Halts and attempts to clean up stack, data memory, and label memory before exiting with given exit code.
- NOP (): Does nothing. Seriously.
- LOAD (reg, val): Loads given integer value into given register.
- MOV (dst, src): Copies contents of src register into dst register.
- ADD (): Pops the top two integers from the stack and pushes their sum.
- SUB (): Pops the top two integers from the stack and pushes the difference (lower minus upper).
- MUL (): Pops the top two integers from the stack and pushes their product.
- MOD (rega, regb): Computes rega % regb and stores in ERX.
- REM (reg): Stores ERX in given register.
- NOT (reg): Computes bitwise NOT of reg and stores in reg.
- XOR (rega, regb): Computes rega ^ regb and stores in rega.
- OR (rega, regb): Computes rega | regb and stores in rega.
- AND (rega, regb): Computes rega & regb and stores in rega.
- INCR (reg): Increments value in given register.
- DECR (reg): Decrements value in given register.
- INC (): Increments the value at the top of the stack.
- DEC (): Decrements the value at the top of the stack.
- PUSHR (reg): Pushes value in given register.
- PUSH (val): Pushes given value.
- POP (val): Pops an integer from the stack and dumps it into GBG.
- JZ (addr): Jumps to given absolute address if value in EAX is 0.
- RJZ (diff): Adds differential to current EIP (relative jump) if value in EAX is 0.
- JNZ (addr): Jumps to given absolute address if value in EAX is not 0.
- RJNZ (diff): Adds differential to current EIP (relative jump) if value in EAX is not 0.
- JMP (addr): Jumps to given absolute address.
- RJMP (diff): Adds differential to current EIP (relative jump).
- DBS (key, val): Sets data memory at key (string pointer) to given value.
- DBG (key, reg): Gets value from data memory at key (string pointer) and dumps it into given register.
- CALL (key, nargs): Save state and set EIP to value in data memory at key.
- RET (val): Push return value and load state.
- PREG (reg): Prints contents of given register.
- PTOP (): Peeks top of stack and prints top value.
- REG0 ... REG9: General purpose.
- EAX, EBX, ECX, EDX: Used for cmp, et al.
- ERX: Used for remainder/mod.
- EIP: Instruction pointer. Used for keeping place in code, gotos, calling, etc.
- ESP: Stack pointer. Not currently in use; stack implementation is separate.
- GBG: Garbage register mainly used for popping.
One way:
- Check out the TODO.md file to see if anything needs doing.
- Write some code (following existing implicit style) and submit a pull request.
Another way:
- Write some code for a feauture you want to exist and submit a pull request.
GPLv3. See LICENSE.txt.