Assembler and disassembler designed specifically for Game Boy Advance homebrew.
The assembler works for ARM and Thumb code, and has features like conditional compilation, defined constants and functions, struct layout, compile-time scripts, literal pools, and incremental builds.
The disassembler is experimental, and includes a partially implemented ARM emulator.
You'll need to install deno on your operating system.
Then run:
# install the latest release of deno
deno upgrade
# install the latest release of gvasm
deno install -g --allow-read --allow-write --allow-run -f -r \
https://raw.githubusercontent.com/velipso/gvasm/main/gvasm.tsIf this is your first time running deno install, you will need to add the deno binary directory to
your path. See the page on deno install
for more information.
In order to upgrade, simply run the above command again -- it will redownload the latest version and install it.
You can verify everything installed correctly by running the internal test suite:
gvasm itestEvery test should pass!
Read the assembler manual.
Start by initializing a new file:
gvasm init MyGame.gvasmThis will create MyGame.gvasm in your current directory with a small example program.
You can build this file via:
gvasm make MyGame.gvasmThis will output MyGame.gba, which can be ran inside emulators. The example program just sets the
background color to green.
If you want to play with the disassembler, you can try:
gvasm dis gba_bios.binThe emulator can run code, which is useful for quickly debugging a section of code. For example, this works:
// test.gvasm
.thumb
ldr r0, =300
again:
_log "r0 = %d", r0
subs r0, #1
cmp r0, #250
bne again
_log "done"
_exit
.pool
Then:
gvasm run test.gvasmThis will execute the code, along with debug statements like _log and _exit, producing the
output:
r0 = 300
r0 = 299
...
r0 = 251
done
If your project uses the older gvasm v1, you can still install the latest release prior to v2 by
using the v1.9.4 tag:
deno install --allow-read --allow-write -f -r \
https://raw.githubusercontent.com/velipso/gvasm/v1.9.4/gvasm.ts- ARM7TDMI Tech Spec (mirror)
- ARM7TDMI Data Sheet (mirror)
- ARM7TDMI Instruction Set (mirror)
- Error on PDF page 18 (labeled "Page 16"), it gives the incorrect encoding for CMN instruction
- CowBite Hardware Spec (mirror)
- GBATEK No$GBA (mirror)