[Oberon] RISC-5 and memory

[Tomas Kral]

On Fri, 6 Oct 2017 20:52:18 +0000
"Skulski, Wojciech" <skulski at pas.rochester.edu> wrote:

> Today the students launched Pepino. 

> Sometimes The System froze, sometimes it threw a bunch of traps, and
> sometimes it behaved gracefully. So there is a bug in Stars.Mod.
> Also, I did not like that the mouse pointer wraps around the screen.

Hi Wojtek,

My experience with mice, there exist three driver types
`MouseX' - for Ceres Mouse, seen on photographs in PO2013
`MouseP' - general for PS/2 style modern mice
`MouseM' - as above supporting Microsoft protocol

I use `MouseP' for Genius scroll mouse, weeller acting as the middle
button. `MouseM' did not work with it well, and indeed caused some
TRAP time to time.  

The first exercise Magnus let me do on my own was to replace `MouseM'
for `MouseP' and do full h/w synthesis in Xilinx ISE :-)

Requires adding/removing relevant mouse source files, plus modifying
top module.

Also make sure you have the latest OB, I usually build a new image
with fresh install of OB plus all PO2013 modules. Then I add over
line my own modules making my development environment.

I could share at git, OB as of 19.4.2017 should you wish to
compare with versions of your install.

Interesting discovery for the students also might be, that system
is non-preemptive, sake of simplicity. You may consider installing
a simple ABORT button as I did initially, see picture, connects to
BTN[3]. (later Magnus added logic to push button, doing also full h/w
reset). This lets the system step out from endless loops without
resetting machine, usually a result of badly formed loop conditions,
that happens to me frequently :-)

Tomas

-- 
Tomas Kral <thomas.kral at email.cz>
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