B.F.G.

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BFG is an optimised Brainfuck interpreter written in Go.

Uses signed ints for data (platform specific 32/64), memory wraps around at 65535, EOF returns -1.

Optionally uses 8 bit data cells.

Buffered output flushes on newline, 200 chars or input.

Optimisations

Operates with a instruction parse then execute pattern.

• loop start/end are calculated up front.
• repeat ++++ or --- are replaced with a single addition/subtraction
• [-] is converted to a blind set 0 command
• addition/subtraction after zero does a blind set.
• repeat >>> or <<< are replaced with a single pointer jump
• [>>>] is merged into a skip instruction.
• [>>+<<-] is merged into a move instruction.
• [<+++++>-] is converted to a multiply instruction.
• [<<+>+>-] is converted to a duplicate instruction.
• and dead code removal.

for performance comparison see no_optimisation branch.

Usage

Usage:
  bfg [option] source.bf [input]

Options:
  -e, --eight	eight bit execution
  -p, --print	pretty print parsed program
  -v, --version	display version

May use - as source to read program from STDIN and output is STDOUT

#!/usr/bin/env bf
+++++++++[>++++++++>++++++++++++>++++>++++++++++++>+++++++++++>+<<<<<<-]>---.>++
.----.+++++.++++++++++.>----.<-----.>>----.+.<<-.>.<<---.>-.>>>--.<.+++++.<<<+++
+.>+++.>>>++.<---.<+.>>>+.