waterbear

waterbear is an assembler/disassembler for the Dreamcast VMU.

Download

You can download prebuilt binaries from here: waterbear latest release.

Usage

To assemble a file, use the waterbear assemble command:

waterbear assemble example.s -o example.vms

Reference

Info

waterbear aims to be a robust, easy-to-use tool, and meant to make VMU programming bit more approachable.

The error messages are designed to make it easy to find out what went wrong where:

% waterbear assemble example.s -o example.vms
[ERROR] Failed to assemble example.s

✘ Name already exists: my_var

The name found here...
example.s:3:0-12
  my_var = $49
  ^^^^^^^^^^^^ Duplicate

...was already declared here
example.s:2:0-12
  my_var = $48
  ^^^^^^^^^^^^ Original

Additionally, waterbear has a macro system.

%macro  Safe_8bit_Add   %op
  ; Adds an 8bit number to acc and prevents overflow by maxing acc
  ; if detected
  add     %op
  bn      psw, 7, .no_carry%
  mov     #$ff, acc
.no_carry%
%end

The error message will help with macro expansion as well, walking you through which macro expansions occured to generate the invalid code.

% waterbear assemble example.s -o example.vms
[ERROR] Failed to assemble example.s

✘ Wrong arguments for instruction add.

example.s:9:8-22
          add     %op, 7
          ^^^^^^^^^^^^^^
  | 
  | ...expanded from
  | 
  | example.s:16:2-20
  |     Safe_8bit_Add %val
  |     ^^^^^^^^^^^^^^^^^^
  | 
  | ...expanded from
  | 
  | example.s:19:0-14
  |   Foo 100 + 1000
  |   ^^^^^^^^^^^^^^

Allowed forms for instruction add:
  add #i8
  add d9
  add @Ri

In this example, you can see the ...expanded from sections, showing each step of multiple nested macro expansions.

Credits

These are people who have either directly or indirectly helped with the development of waterbear.

Name	Contribution
Falco Girgis	ElysianVMU - VMU Emulator
Kresna Susila	VMU assembly programmer/game developer
Marcus Comstedt	Author of the aslc86k assembler, softvms emulator, hardware documentation, and tetris VMU game
John Maushammer	Author of the lcdis disassembler