EightBol - EIGHTBOL Compiler for 8-bit Systems

EightBol is an EIGHTBOL compiler that targets 8-bit microprocessors.

Eight-Bit-Oriented-Language.

There will also be support for some 16-bit CPUs.

Usage

eightbol --version

eightbol --help

eightbol src/my-cool-file.cob -o obj/my-cool-file.s -m 6502 -I lib/

Output stages supported

• 6502 (implemented)
• 65c02 (implemented, derived from 6502)
• 65c816 (implemented, derived from 6502)
• HuC6280 (implemented, derived from 6502)
• RP2A03 (implemented, NES CPU, derived from 6502)
• cp1610 (implemented, Intellivision)
• Z80 (implemented)
• SM83 (implemented, Game Boy)
• m68k (implemented, Motorola 68000)
• i286 (implemented, Intel 80286)
• ARM7 (implemented, ARM7TDMI)

Pipeline

Source/Classes/{ClassName}.cob
  │
  ├─ Lexer (lexer.lisp) — COPY expansion inline at lex time
  │     ↓
  ├─ YACC Parser (parser.lisp) → AST plist
  │     ↓  written to Object/Classes/{ClassName}.eightbol
  │
  └─ Backends — one per CPU
        ↓  written to Source/Generated/Classes/{cpu}/{ClassName}.s

Supported Statements

• MOVE — MOVE source TO destination
• ADD — ADD x TO y; ADD x TO y GIVING z
• SUBTRACT — SUBTRACT x FROM y; SUBTRACT x FROM y GIVING z
• COMPUTE — COMPUTE x = expression
• IF/THEN/ELSE — conditional execution
• PERFORM — PERFORM procedure-name; PERFORM UNTIL/THRU
• INVOKE — INVOKE object method-name (6502 family: INVOKE Self expands to the Phantasia .CallMethod macro, same as INVOKE on a typed object reference; see doc/EIGHTBOL.texi §6502 ABI)
• STRING — STRING source DELIMITED BY SIZE INTO dest (block transfer only); supports reference modification name(start:length)
• SET — SET identifier TO expression (only)
• CALL, CANCEL, GOBACK, EXIT METHOD, LOG FAULT, BREAK

Supported (parser + backends)

• INSPECT — TALLYING, CONVERTING, REPLACING CHARACTERS (all backends)
• EVALUATE — WHEN clauses (all backends)
• Subscripted access — MOVE arr(idx) TO x, MOVE x TO arr(idx), etc.

Unsupported (compile-time error)

• DIVIDE, MULTIPLY
• STRING with character delimiter (use DELIMITED BY SIZE for BLT)
• UNSTRING
• GOTO / GO TO
• SET — UP BY, DOWN BY, TO NULL/NULLS/SELF, TO ADDRESS OF, condition-name TO TRUE

Testing

Run the test suite:

(asdf:test-system :eightbol)

Tests cover:

• Lexer — tokenization, prefixed literals, reference modification, picture-sequence, COPY expansion
• Parser — class structure, methods, statements (MOVE, ADD, SUBTRACT, COMPUTE, SET, IF, INVOKE), subscript
• AST — node structure (move, add, subtract, compute, set, refmod, string-blt), write/read round-trip
• Unsupported statements — DIVIDE, MULTIPLY, UNSTRING, GOTO, SET variants signal compile-time error
• STRING BLT — DELIMITED BY SIZE with reference modification name(start:length)
• Backends — 6502, 65c02, 65c816, cp1610, Z80, m68k, SM83, i286, ARM7; shift/bit ops; subscript

EIGHTBOL Copybooks

Class slot definitions are generated automatically by make-classes-for-oops from Source/Classes/Classes.Defs into Source/Generated/{ClassName}.cpy. These are included into .cob files via COPY ClassName.

COPY is required. If a copybook cannot be found, the compiler signals a fatal error. COPY statements cannot be ignored.

Dependency tracking. The compiler writes Source/Generated/Classes/{ClassName}.d (Makefile dependency format) listing all assembly outputs and their dependencies (the .cob source plus every copybook resolved during lex). Include these in your Makefile for correct rebuilds when copybooks change.

Slot annotations in Classes.Defs:

• .SlotName size — default PIC (1 byte → PIC 99, 2 bytes → PIC 9999, n bytes → OCCURS n)
• .SlotName size @ClassName — OBJECT REFERENCE ClassName pointer
• .SlotName size = PIC-string — verbatim PIC clause
• .SlotName size = VARCHAR(n) DEPENDING ON Field — variable-length string (correct COBOL: PIC X OCCURS 0 TO n TIMES DEPENDING ON Field)

License

MIT License - see LICENSE file for details.