[Oberon] FPGA Oberon Article in Xilinx Xcell Journal (Issue 91)

[Michael Schierl]

Am 13.05.2015 um 15:15 schrieb Srinivas Nayak:

> Good to see the article.
> Here is the pdf.
> www.xilinx.com/publications/archives/xcell/Xcell91.pdf

Quoted from the article:

"In fact, system integrity can be violated only by the use of operations
in the pseudo-module SYSTEM, namely PUT and COPY"


That's wishful thinking... System integrity can easily be violated by
accessing uninitialized variables on the stack (it is left as an
exercise to the reader to abuse this for implementing SYSTEM.PUT for the
RISC processor in pure Oberon without importing the SYSTEM module). And
there is no easy way of fixing this that does not impact performance
(like initializing all variables on the stack), as the Oberon language
neither has a notion of uninitialized variables, nor of "out" parameters.

I think the bug in System.Clear that sometimes overwrites some random
piece of memory due to accessing an uninitialized pointer has not been
fixed yet in the source published on Project Oberon, either.


But apart from that, I like the article, too :)


Regards,


Michael