mirror of
https://github.com/hsoft/collapseos.git
synced 2024-12-26 15:28:06 +11:00
60 lines
2.2 KiB
Markdown
60 lines
2.2 KiB
Markdown
# emul
|
|
|
|
This folder contains a couple of tools running under the [libz80][libz80]
|
|
emulator.
|
|
|
|
## Build
|
|
|
|
First, make sure that the `libz80` git submodule is checked out. If not, run
|
|
`git submodule init && git submodule update`.
|
|
|
|
After that, you can run `make` and it builds all tools.
|
|
|
|
## shell
|
|
|
|
Running `shell/shell` runs the shell in an emulated machine. The goal of this
|
|
machine is not to simulate real hardware, but rather to serve as a development
|
|
platform. What we do here is we emulate the z80 part, the 64K memory space and
|
|
then hook some fake I/Os to stdin, stdout and a small storage device that is
|
|
suitable for Collapse OS's filesystem to run on.
|
|
|
|
Through that, it becomes easier to develop userspace applications for Collapse
|
|
OS.
|
|
|
|
We don't try to emulate real hardware to ease the development of device drivers
|
|
because so far, I don't see the advantage of emulation versus running code on
|
|
the real thing.
|
|
|
|
## zasm
|
|
|
|
`zasm/zasm` is `apps/zasm` wrapped in an emulator. It is quite central to the
|
|
Collapse OS project because it's used to assemble everything, including itself!
|
|
|
|
The program takes no parameter. It reads source code from stdin and spits
|
|
binary in stdout. It supports includes and had both `apps/` and `kernel` folder
|
|
packed into a CFS that was statically included in the executable at compile
|
|
time.
|
|
|
|
The file `zasm/zasm.bin` is a compiled binary for `apps/zasm/glue.asm` and
|
|
`zasm/kernel.bin` is a compiled binary for `tools/emul/zasm/glue.asm`. It is
|
|
used to bootstrap the assembling process so that no assembler other than zasm
|
|
is required to build Collapse OS.
|
|
|
|
This binary is fed to libz80 to produce the `zasm/zasm` "modern" binary and
|
|
once you have that, you can recreate `zasm/zasm.bin` and `zasm/kernel.bin`.
|
|
|
|
This is why it's included as a binary in the repo, but yes, it's redundant with
|
|
the source code.
|
|
|
|
Those binaries can be updated with the `make updatebootstrap` command. If they
|
|
are up-to date and that zasm isn't broken, this command should output the same
|
|
binary as before.
|
|
|
|
## runbin
|
|
|
|
This is a very simple tool that reads binary z80 code from stdin, loads it in
|
|
memory starting at address 0 and then run the code until it halts. The exit
|
|
code of the program is the value of `A` when the program halts.
|
|
|
|
This is used for unit tests.
|