planckforth: Bootstrapping a Forth interpreter from hand-written tiny ELF binary

Hacker News · Feb 16, 2026 · Collected from RSS

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PlanckForth: Bootstrapping an Interpreter from Handwritten 1KB Binary This project aims to bootstrap a Forth interpreter from hand-written tiny (1KB) ELF binary. This is just for fun. No practical use. How to build Only xxd is needed to build PlanckForth. $ git clone https://github.com/nineties/planckforth.git $ cd planckforth $ make xxd -r -c 8 planck.xxd > planck chmod +x planck Implementations in other languages are in others. Hello World The hello world program at the beginning looks like this. $ ./planck kHtketkltkltkotk tkWtkotkrtkltkdtk!tk:k0-tk0k0-Q After bootstrapping by bootstrap.fs, it looks like this. $ ./planck < bootstrap.fs ." Hello World!" cr bootstrap.fs can also take a file as an input program like this. $ cat example/fib.fs : fib dup 2 < unless 1- dup recurse swap 1- recurse + then ; 20 fib . cr $ ./planck < bootstrap.fs example/fib.fs 6765 Running Tests $ make test Builtin Words code name stack effect semantics Q quit ( n -- ) Exit the process C cell ( -- n ) The size of Cells h &here ( -- a-addr ) The address of 'here' cell l &latest ( -- a-addr ) The address of 'latest' cell k key ( -- c ) Read character t type ( c -- ) Print character j jump ( -- ) Unconditional branch J 0jump ( n -- ) Jump if a == 0 f find ( c -- xt ) Get execution token of c x execute ( xt -- ... ) Run the execution token @ fetch ( a-addr -- w ) Load value from addr ! store ( w a-addr -- ) Store value to addr ? cfetch ( c-addr -- c ) Load byte from addr with sign extension $ cstore ( c c-addr -- ) Store byte to addr d dfetch ( -- a-addr ) Get data stack pointer D dstore ( a-addr -- ) Set data stack pointer r rfetch ( -- a-addr ) Get return stack pointer R rstore ( a-addr -- ) Set return stack pointer i docol ( -- a-addr ) Get the code pointer of interpreter e exit ( -- ) Exit current function L lit ( -- n ) Load immediate S litstring ( -- c-addr ) Load string literal + add ( a b -- c ) c = (a + b) - sub ( a b -- c ) c = (a - b) * mul ( a b -- c ) c = (a * b) / divmod ( a b -- c d ) c = (a mod b), d = (a / b) & and ( a b -- c ) c = (a & b) | or ( a b -- c ) c = (a | b) ^ xor ( a b -- c ) c = (a ^ b) < less ( a b -- c ) c = (a < b) u uless ( a b -- c ) c = (a unsigned< b) = equal ( a b -- c ) c = (a == b) ( shl ( a b -- c ) c = a << b (logical) ) shr ( a b -- c ) c = a >> b (logical) % sar ( a b -- c ) c = a >> b (arithmetic) v argv ( -- a-addr u ) argv and argc V version ( -- c-addr ) Runtime infomation string Binary Layout Implementations Implementation of runtime build test status Handwritten ELF binary for i386-linux make C make c Python 3.x make python Benchmarks See Wiki/Benchmarks