wadimiusz/budivelnyk

assembly language experiments

budivelnyk

Budivelnyk is a compiler from bf to asm. The name comes from Ukrainian будівельник 'builder'.

Supported input

Currently, bf is the only language we support. A cell is one byte large. 255 + 1 = 0 and 0 - 1 = 255. Leaving tape boundaries may or may not cause segmentation fault.

Supported targets

Supported targets currently are:

• Linux on x86_64 (Intel syntax)
• Linux on x86_64 (AT&T syntax)

Usage

Example usage:

from budivelnyk import bf_to_asm, Target

bf_to_asm("input.bf", "output.s", target=X86_64_ATT)

The produced asm code can be manually assembled and linked to a shared library (currently only tested with gcc). You can also use the bf_to_shared helper function to create asm and the shared library directly from bf code:

from budivelnyk import bf_to_shared

bf_to_shared("input.bf", "output.s", "liboutput.so")

Currently, the compiler always generates exactly one function named run that you can use as if its definition were void run(char*). The created library can be used from any language that supports loading a shared library and passing a byte array to a function from that library.

Memory for the tape has to be allocated by the caller. This has the following advantages:

• If you know in advance that your code only requires a few bytes to run, you don't have to allocate a large tape.
• You can pre-fill the tape with input data and inspect the modified tape after the bf program exits, which leads to composable bf programs.

You may also give the program a pointer to the middle of the tape and not the beginning (but this probably has no practical use).

Optimisations

The compiler performs simple optimisations like folding every sequence of the form +++++ or << into one assembly instruction.