Porting GW-BASIC for the MSX

Supporter (2)

30-05-2020, 22:18

Hey --

First post here.

Recently, Microsoft released the source code of GW-BASIC for MS-DOS under a permissive open source license. It's been mechanically translated from 8080/Z80 to 8086, so I'm working on a tool to mechanically convert it back to Z80 with the intention of making it run on the MSX.

So far, I've made good progress, but there's still a lot of work to do.

The source code is available here (https://github.com/lpereira/gw-basic). The ASM files are the original 8086 sources, but most of them can be passed through the conversion tool (conv.py) to generate Z80 source code. The code does not assemble yet, and some of it isn't even valid Z80 (this is my first foray into Z80 programming), but I'm fixing stuff slowly and steadly.

I'm here looking for help from other people that might be interested in having a open source Microsoft BASIC on the MSX. I know the C-BIOS people might be interested in this.

Cheers,
Leandro

By Manuel

Ascended (19465)

31-05-2020, 00:27

Wow, interesting idea to use it as a base for a BASIC for C-BIOS. The problem with GW-BASIC is that it is not aware of any of the MSX hardware though... so I suppose you will have to add a lot of MSX specific stuff, also making use of the MSX-BIOS (or C-BIOS) routines.

By zeilemaker54

Champion (347)

31-05-2020, 00:46

The source code (recreated by disassmbly) of MSX basic is already available, see my msxsysrc project https://sourceforge.net/projects/msxsyssrc/
I did a quick compare on the important parts and they are pretty much the same. It is easy to see that the code is in fact a translation of the original i8080 code.

By lpereira

Supporter (2)

31-05-2020, 01:04

Quote:

The problem with GW-BASIC is that it is not aware of any of the MSX hardware though...

Yes, it's just a starting point to have a BASIC that's somewhat compatible with the MSX BASIC and that is freely usable/distributable without copyright issues. It's going to take a while to support all the hardware, and even then, to achieve good compatibility with the current versions of MSX BASIC in terms of peripheral access.

The code is segregated into generic and platform-specific routines, so it should be possible to write drivers for things like VDP, PSG, and whatnot, and some things should "just work". Others will need some love; even the PSG will, as the PLAY command only supports one channel at the moment.

But one step at a time. I would be happy if I could get it to run a 10 ?"hello": goto 10 kind of program.

Quote:

The source code (recreated by disassmbly) of MSX basic is already available

Also, the fact that the MSX BASIC disassembly is available doesn't mean you can freely use it. The code in msxsyssrc is in a grey area because it's not licensed under any open source license (it's disassembled proprietary code); it can't be used for C-BIOS, for instance.

By Grauw

Ascended (10768)

31-05-2020, 01:29

Super cool project! And I didn’t know GW-BASIC was MIT licensed, that’s mighty nice of Microsoft.

By Louthrax

Prophet (2465)

31-05-2020, 09:53

Interesting indeed. Any different and interesting features in GW BASIC language that we do not have in MSX ?

By Manuel

Ascended (19465)

31-05-2020, 10:00

Doesn't it have WHILE/WEND?

By mars2000you

Enlighted (6481)

31-05-2020, 10:42

Manuel wrote:

Doesn't it have WHILE/WEND?

Yes: http://robhagemans.github.io/pcbasic/doc/1.2/#WHILE or http://robhagemans.github.io/pcbasic/doc/2.0/#WHILE

Check this GW-BASIC emulator http://robhagemans.github.io/pcbasic/index.html

and its detailed doc: http://robhagemans.github.io/pcbasic/doc/1.2/ or http://robhagemans.github.io/pcbasic/doc/2.0/

By zeilemaker54

Champion (347)

31-05-2020, 11:24

Quote:

The source code (recreated by disassmbly) of MSX basic is already available

I think now is the time to ask Microsoft to open source MSX basic. There is no point not to open source it, because it is created from the same source code as GW basic. The code of GW basic has even the i8080/z80 register named in comments. It is the same thing

By lintweaker

Champion (464)

31-05-2020, 12:14

zeilemaker54][quote wrote:

Will / can probably not happen, from the blog:

What about other ports?

Many have asked if we can also open-source implementations for processors other than the 808x. Alas, we’re unable to provide sources for these ports and/or customizations.

By mars2000you

Enlighted (6481)

31-05-2020, 12:33

Easier to read with quote tag:

Quote:

What about other ports?

Many have asked if we can also open-source implementations for processors other than the 808x. Alas, we’re unable to provide sources for these ports and/or customizations.