[fpc-devel] Episode 4. Addressing and it's limits Part Two

[Mark Morgan Lloyd]

Hans-Peter Diettrich wrote:
> Tomas Hajny schrieb:
> 
>> The Intel x86 (and thus also Pentium) opcodes like "AAD" ("ASCII 
>> adjust before division"), etc., suggest some dependency, but I admit 
>> that I didn't try to analyze what results it would have with EBCDIC.
> 
> BCD values are stored as "nibbles" (4 bit binary values), which are 
> independent from character codes. A nibble happens to represent the low 
> 4 bits of the digits, in both ASCII and EBCDIC.

In any event, I'd not expect somebody who'd spent their career focussed 
on mainframes to be sufficiently familiar with x86 assembler to be able 
to make informed criticism at this level of detail. Similarly I'd not 
expect somebody who'd spent their career focussed on PCs to be able to 
make informed criticism of mainframe I/O architecture and the claimed 
throughput levels.

As I've already said, there's a lot of disinformation been disseminated, 
and I think it behooves both sides to admit that both mainframes and PCs 
(and their derivatives, which appear to include everything from large 
servers down to smartphones) have their place and aren't going away.

-- 
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]