BrainFuck Interpreter

version 2.0.0

Overview

Standard Brainfuck

+ increase
- decrease
> move right
< move left
[ loop beginning
] loop end
. output to stdout
, read from stdin

Extension

# make a socket call
% make a syscall
@ call function ( exit while read tape from stdin )
$ Preprocessor

All the number is Big-endian

System call

the pointing cell, called cell 0, and the next 3 cells store the number of the system call. ( as an 32bit Big-endian unsigned integer ) the next cell, cell 4, is the count of arguments. cell 5 ~: arguments result: will fill cell 0, cell 1, ... in the endian depending on your hardware.

There are 3 types of arguments, normal, contents pointer, and pointer to cell.

Functions

• cell 0: number of the function Calling a function won't reset the memory, just like fork The returning value:
• 'cell 0': length of value The returning value will be copy to caller's memory tape from the position it called the function.

Preprocessor

To unify the number of function calls, we introduced a C-like preprocessor. for example, you wrote a function f in header.h, and you want to use it in main.c

/* main.c */
#include "header.h"

as C, we can do same thing in bf

$++++++++++[>++++++++++<-]>[-<+>]<[->+>+>+>+>+>+<<<<<<]>+>--->>+>++++++++++++++>[-<<<<<<+>>>>>>]<<<<<<++++

equal to $header in plain text, to include "header" as a function tape.

The functions' index are count from 1 because function 0 is the tape itself.

SocketCall

Equal to

int syscall( SYS\_socketcall, `Cell 0`, `Cell 1~` );

on some architecture of Linux kernels.

• Cell 0: SocketCall number returning value: Cell 0~

if the argument is a pointer, address of the beginning cell will be passed to and it'll be the last argument. E.g. recv( int, void*, size_t, int ); cells should contain ( int, size_t, int, ... ).

Usage

The source code was written in GNU99 standard

Build

make

or

make all

Install

sudo make install

will be install to /opt/homobf and add 2 files to /etc/profile.d

Use

Interactive interface

./homobf #without installing

homobf #installed

Interpreter

./homobf maintape.bf #without installing

homobf maintape.bf

Reference

• systemf by Yoon