[Oberon] Re (2): Other CONST.

[peter at easthope.ca]

From:	Paul Reed <paulreed at paddedcell.com>
Date:	Sun, 6 Jan 2019 23:16:39 +0000
> ... since -24 and -20 (0FFFFFFE8H and FFFFFFECH) are defined by the
> emulator presumably for virtual machine to host clipboard purposes, you
> don't see those particular addresses in Prof. Wirth's document.

Thanks Paul.  To understand, I need to study SDL and Peter's C 
sources.  sdl-clipboard.c and sdl-clipboard.h at least.

Incidentally, during the last year or more, some or much discussion 
has involved the 1 MB memory of the FPGA machine.  Peter has this 
remark at the top of risc.c.

// The FPGA uses a 20-bit address bus and thus ignores the top 12 bits. 
// We use all 32 bits. This allows us to have more than 1 megabyte of 
// RAM.

Meaning that in principle the emulator is no more constrained than a 
32 bit PC.  (?)  Nevertheless, Peter continues,

// We add an extra half megabyte.

He declined to give it enough memory for S3 or V4;  but possible 
... for someone who knows what he's doing; which I don't.

Regards,                         ... Lyall E.

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