libasm: cross assemble/disassemble library

The libasm allows assembling and disassembling supported retro CPUs on a small environment (less than 9kB-17kB Flash and 350B RAM on AVR Arduino).

Assembler library interface

Assembling MC68HC11 instruction in string to binary can be done in a minute. You can also add symbol table lookup via SymbolTable interface.

#include <asm_mc6800.h>
libasm::mc6800::AsmMc6800 asm6800;
asm6800.setCpu("68HC11");

const char *text = "SUBD $90";
libasm::Insn insn{0x1000};

asm6800.encode(text, insn);
assert(insn.getError() == OK);
assert(insn.address()  == 0x1000);
assert(insn.length()   == 2);    // direct addressing
assert(insn.bytes()[0] == 0x93); // SUBD
assert(insn.bytes()[1] == 0x90); // $90

Disassembler library interface

To disassemble MC68000 binaries, you need to wrap memory by ArrayMemory or implements your own DisMemory interface to feed binaries. You can also add symbol table lookup via SymbolTable interface.

#include <dis_mc68000.h>
libasm::mc68000::DisMc68000 dis68k;
dis68k.setOption("relative", "true");

const uint16_t words[] = {0047372, 0x1232};
const libasm::ArrayMemory memory{0x1000, words, sizeof(words)};
libasm::DisMemory dismem = memory.iterator();
libasm::Insn insn{dismem.address()};
char opr[80];

dis68k.decode(dismem, insn, opr, sizeof(opr));
assert(insn.getError() == OK);
assert(insn.address()  == 0x1000);
assert(std::string(insn.name()) == "jmp");
assert(std::string(opr) == "(*+$1234,pc)");

Arduino sketch examples

There are assembler and disassembler example sketches you can try to run on actual Arduino board at examples.

Assembler command line interface

On POSIX environment, assembler command line interface is provided. It can generate Intel HEX or Motorola S-Record output.

libasm assembler (version 1.6.51)
usage: asm [-o <output>] [-l <list>] <input>
  -C <CPU>          : target CPU
     MC6800 MB8861 MC6801 HD6301 MC68HC11 MC6805 MC146805 MC68HC05
     MC68HC08 MC6809 HD6309 MOS6502 R65C02 G65SC02 W65C02S W65C816S i8039
     i8048 i80C39 i80C48 MSM80C39 MSM80C48 i8051 i8080 i8085 V30EMU Z80 Z8
     Z86C Z88 TLCS90 INS8060 INS8070 CDP1802 CDP1804 CDP1804A SCN2650
     F3850 IM6100 HD6120 TMS7000 TMS32010 TMS32015 i8086 i80186 V30 i8096
     MC68000 MC68010 TMS9900 TMS9980 TMS9995 TMS99105 TMS99110 Z8001 Z8002
     NS32032 MN1610 MN1613 MN1613A J11 T11
  -o <output>       : output file
  -l <list>         : list file
  -S[<bytes>]       : output Motorola S-Record format
  -H[<bytes>]       : output Intel HEX format
                    : optional <bytes> specifies data record length (max 32)
  -h                : use lower case letter for hexadecimal
  -n                : output line number to list file
  -v                : print progress verbosely
  --<name>=<vale>   : extra options (<type> [, <CPU>])
  --list-radix      : set listing radix (8, 16) (int)
  --smart-branch    : optimize branch instruction (bool)
  --fpu             : floating point co-processor (text: 8086, 68000, 32032)
  --implicit-word   : unknown instruction defines word (bool: 6100, J11)
  --optimize-index  : optimize zero index (bool: Z8)
  --optimize-segment: optimize segment override (bool: 8086)
  --pc-bits         : program counter width in bit, default 13 (int: 6805)
  --pmmu            : memory management unit (text: 32032)
  --reg-alias       : emit register alias regarding setrp value (bool: Z8)
  --short-direct    : optimize direct addressing (bool: Z8001)
  --use-register    : enable register name Rn (bool: 1802)
  --zilog-syntax    : Use Zilog syntax (bool: 8080)

Disassembler command line interface

On POSIX environment, disassembler command line interface is provided. It can read Intel HEX or Motorola S-Record input.

libasm disassembler (version 1.6.51)
usage: dis -C <CPU> [-o <output>] [-l <list>] <input>
  -C <CPU>         : target CPU
     MC6800 MB8861 MC6801 HD6301 MC68HC11 MC6805 MC146805 MC68HC05
     MC68HC08 MC6809 HD6309 MOS6502 R65C02 G65SC02 W65C02S W65C816S i8039
     i8048 i80C39 i80C48 MSM80C39 MSM80C48 i8051 i8080 i8085 V30EMU Z80 Z8
     Z86C Z88 TLCS90 INS8060 INS8070 CDP1802 CDP1804 CDP1804A SCN2650
     F3850 IM6100 HD6120 TMS7000 TMS32010 TMS32015 i8086 i80186 V30 i8096
     MC68000 MC68010 TMS9900 TMS9980 TMS9995 TMS99105 TMS99110 Z8001 Z8002
     NS32032 MN1610 MN1613 MN1613A J11 T11
  -o <output>      : output file
  -l <list>        : list file
  <input>          : file can be Motorola S-Record or Intel HEX format
  -A start[,end]   : disassemble start address and optional end address
  -r               : use program counter relative notation
  -h               : use lower case letter for hexadecimal
  -u               : use upper case letter for output
  -v               : print progress verbosely
  --<name>=<vale>  : extra options (<type> [, <CPU>])
  --upper-hex      : use upper case letter for hexadecimal (bool)
  --upper-case     : use upper case letter for output (bool)
  --list-radix     : set listing radix (8, 16) (int)
  --relative       : program counter relative branch target (bool)
  --c-style        : C language style number constant (bool)
  --intel-hex      : Intel style hexadecimal (bool)
  --origin-char    : letter for origin symbol (char)
  --external-paren : disp2(disp(ext)) as external addressing (bool: 32032)
  --gnu-as         : GNU assembler compatible (bool: 68000, Z8001, 32032)
  --indirect-long  : [] for indirect long operand (bool: 6502)
  --longa          : enable 16-bit accumulator (bool: 6502)
  --longi          : enable 16-bit index registers (bool: 6502)
  --pc-bits        : program counter width in bit (default 13) (int: 6805)
  --segment-insn   : segment override as instruction (bool: 8086)
  --segmented-addr : use <<segment>> notation (bool: Z8001)
  --short-direct   : use |addr| for short direct notation (bool: Z8001)
  --string-insn    : string instruction as repeat operand (bool: 8086)
  --use-absolute   : zero register indexing as absolute addressing (bool: 8096)
  --use-register   : use register name Rn (bool: 1802)
  --use-sharp      : use # (default =) for immediate (bool: 8070)
  --work-register  : prefer work register name than alias address (bool: Z8)
  --zilog-syntax   : Use Zilog syntax (bool: 8080)

Supported host environment

• Arduino (avr, megaavr, samd, teensy)

• PlatformIO (atmelavr, atmelmegaavr, atmelsam, teensy)

• Linux, macOS (C++14)

More information about this library can be found at GitHub