CCIL

The Caul-Chen Interpreted Language (CCIL) is a dynamically-typed, general-purpose programming language with a syntax reminiscent of C or JavaScript.

This project serves as the reference implementation of the language, and consists of a bytecode compiler, bytecode assembler/disassembler, REPL, and Virtual Machine.

All code is copyright (c) 2025-26 The CCIL Developers and is licensed under GPL-3.0.

Running

All tools (ccil, ccila, ccilb) can be run with the --help option for a full list of options. Below is an incomplete list of useful commands.

Assemble and run CCIL assembly file:

cargo run --bin ccila bytecode_assembly/test.ccila

Assemble CCIL assembly file to binary:

cargo run --bin ccila bytecode_assembly/test.ccila -o bytecode/test.ccilb

Disassemble CCIL binary to assembly:

cargo run --bin ccild bytecode/test.ccilb

Disassemble CCIL binary to assembly file:

cargo run --bin ccild bytecode/test.ccilb -o test_disasm.ccila

Language

Assembly

A CCIL assembly program consists of a newline-separated sequence of operations. Each operation is a symbol followed by zero or more more numerical arguments. The number and bounds of arguments depends on the operation. For example:

nop
const 2
const 3
add
pop

Bytecode

A CCIL binary program, or a chunk of bytecode in the CCIL virtual machine, consists of a 16-byte header followed by a list of operations.

The header consists of magic number 0xCC17, three one-byte version numbers (major, minor, patch), a byte used for metadata flags (such as whether the program was compiled from source or from assembly), the 32-bit UTC Unix timestamp in seconds (little-endian), and padding to 16 bytes.

Each operation consists of a one-byte opcode followed by zero or more four-byte little-endian arguments. The number and bounds of arguments depends on the operation. For example,

nop
const 2
pop

compiled from assembly by CCIL v1.2.3 at 9:11:53 AM UTC on January 26, 2026 is encoded as

CC17 0102 0301 D72F 7769 0000 0000 0000 0001 0200 0000 02

breakdown:

.================ HEADER ================.
CC 17                        -- magic num
01 02 03                     -- v1.2.3
01                           -- bitflags
D7 2F 77 69                  -- timestamp
00 00 00 00 00 00            -- padding
'========================================'
.================ PROGRAM ===============.
00                           -- nop
01 02000000                  -- const 2
02                           -- pop
'========================================'