Porting Atom under Risc OS

discussion of games, software, hardware & emulators relating to the Acorn Atom
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Porting Atom under Risc OS

Postby gob33 » Sat Dec 09, 2017 1:44 pm

I got an idea.

It seems to me when reading the forum that it becomes difficult to make evolving the Atom because of the limitations of the 6502,.. and old electronic components disponibility. In addition, everyone does not have the skills in soldering iron, schematics and oscilloscope.

I propose to drop the construction of any specific hardware for the benefit of the [Raspberry Pi + Risc OS] platform.

There is already in Risc OS an ARM port of BBC Basic (ARM BASIC or BBC BASIC VI) made by Sophie Wilson: it can be run in a window or in command mode where the GUI is suspended.


arm bbc basic.jpg


Why not do the same with the Atom interpreter ?

It would be enough to transform atom Interpreter into C code from assembly code 6502 (decompiler) or the BNF grammar, before recompilation under ARM to make like an intern Risc OS emulator.

As Atom Basic is less evolved than the BBC Basic, another option would be keep ARM BBC Basic and turn all programs in the Atom repository into ARM BBC code. There is already a 6502 patch for ARM BBC Basic by John Kortink to include a 6502 assembler.

On Atom, I am fed up with the 32x16 display, poor set of colors and graphic modes, 64K memory limitation, floating point, ...
Need something new, powerfull and easy as the original.

What do you think of ?
Last edited by gob33 on Sat Dec 30, 2017 5:05 pm, edited 4 times in total.

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Re: Porting Atom under Risc OS

Postby roland » Sat Dec 09, 2017 10:24 pm

Isn't it possible ro port Atomulator to RiscOS?
Btw ... Nice hat. I'll port it to my Atom :wink:
256K + 6502 Inside
MAN WOMAN :shock:

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Re: Porting Atom under Risc OS

Postby oss003 » Sun Dec 10, 2017 11:00 am

It should be possible but Atom Basic is not as structured as BBC Basic.

In the Basic #Cxxx ROM, there's one read at #B001 for reading the status of the ESCAPE key which is hardware depending and should be rewritten.
Also not all Basic commands are in the Basic #Cxxx ROM, the commands PLOT, DRAW, MOVE, CLEAR, DIM, OLD and WAIT are in the MOS #Fxxx ROM.
You still be missing the Floating Point #Dxxx functions, so to use them you also have to port the Floating Point ROM.


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Re: Porting Atom under Risc OS

Postby gob33 » Sun Dec 10, 2017 2:07 pm

I was thinking of something more integrated inside RiscOS like having access to the host file system; but an Atom emulator (Atomulateur) should be possible at first step by recompiling with GCC and UnixLib.
Also BeedIt, a Risc OS BBC emulator, could be usefull as a starting point.

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Re: Porting Atom under Risc OS

Postby gob33 » Tue Dec 26, 2017 1:52 pm

I recommend using an Aluminium Case for cooling the Pi 3 like this one (25 EUR) which gives full access to the GPIO port for mounting hats, not like the FLIRC case, the Mechatronics case has a pins extension in option:


Last edited by gob33 on Sun Jan 14, 2018 5:20 pm, edited 2 times in total.

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Re: Porting Atom under Risc OS

Postby crj » Tue Dec 26, 2017 11:40 pm

Presumably an aluminium case makes the WiFi+BT models sad, though?

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Re: Porting Atom under Risc OS

Postby gob33 » Wed Dec 27, 2017 12:16 am

No because there is a smoked acrylic plate on the front that allows the transmission of WIFI and Bluetooth waves and the reading of the two control LEDs.

And on the FLIRC with full alu case, the wifi attenuation is something small if i remember.

I am wondering if an Atom Emulator / Simulator could be written in ARM Basic (BBC Basic VI) itself: It is fast, has more instructions as its ancestor ATOM BASIC, has floating point arithmetics conform to IEEE standard 754, has VDU calls passed to Risc OS.
Need a 6502 asm on ARM asm.
Like an AtomBox program for Risc OS capable of running all atom software libray.

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