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 1.6.47)
usage: asm [-o <output>] [-l <list>] <input>
  -C <CPU>    : target CPU
                MC6800 MB8861 MC6801 HD6301 MC68HC11 MC6805 MC146805
                MC68HC05 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
                TMS9900 TMS9980 TMS9995 TMS99105 Z8001 Z8002 NS32032 MN1610
                MN1613 MN1613A
  -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 lowe 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)
  pc-bits         : program counter width in bit, default 13  (int, 6805)
  setdp           : set direct page register  (int, 6809)
  longa           : enable 16-bit accumulator  (bool, 6502)
  longi           : enable 16-bit index registers  (bool, 6502)
  reg-alias       : emit register alias regarding setrp value  (bool, Z8)
  setrp           : set register pointer  (int, Z8)
  setrp0          : set register pointer 0  (int, Z8)
  setrp1          : set register pointer 1  (int, Z8)
  optimize-index  : optimize zero index  (bool, Z8)
  use-register    : enable register name Rn  (bool, 1802)
  optimize-segment: enable optimizing segment override  (bool, 8086)
  short-direct    : enable optimizing direct addressing  (bool, Z8001)
  pmmu            : memory management unit  (text, 32032)

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 1.6.47)
usage: dis -C <CPU> [-o <output>] [-l <list>] <input>
  -C <CPU>    : target CPU
                MC6800 MB8861 MC6801 HD6301 MC68HC11 MC6805 MC146805
                MC68HC05 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
                TMS9900 TMS9980 TMS9995 TMS99105 Z8001 Z8002 NS32032 MN1610
                MN1613 MN1613A
  -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>])
  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)
  pc-bits         : program counter width in bit (default 13)  (int, 6805)
  longa           : enable 16-bit accumulator  (bool, 6502)
  longi           : enable 16-bit index registers  (bool, 6502)
  indirect-long   : [] for indirect long operand  (bool, 6502)
  work-register   : prefer work register name than alias address  (bool, Z8)
  use-sharp       : use # (default =) for immediate  (bool, 8070)
  use-register    : use register name Rn  (bool, 1802)
  ignore-literal  : Ignore literal constant  (bool, 6100)
  segment-insn    : segment override as instruction  (bool, 8086)
  string-insn     : string instruction as repeat operand  (bool, 8086)
  use-absolute    : zero register indexing as absolute addressing  (bool, 8096)
  short-direct    : use |addr| for short direct notation  (bool, Z8001)
  segmented-addr  : use <<segment>> notation  (bool, Z8001)
  ioaddr-prefix   : I/O address prefix # (default none)  (bool, Z8001)
  pcrel-paren     : addr(pc) as program counter relative  (bool, 32032)
  external-paren  : disp2(disp(ext)) as external addressing  (bool, 32032)
  stropt-bracket  : string instruction operand in []  (bool, 32032)
  float-prefix    : float prefix 0F/0L (default none)  (bool, 32032)

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