Comments | litwr: Emotional stories about processors for first computers: part 9 (Acorn ARM)

litwr

Emotional stories about processors for first computers: part 9 (Acorn ARM)

Oct 06, 2018 22:17

The first ARM processors

The ARM-1 processor was an astonishing development, it continued the 6502 ideology (namely to make a processor that is easier, cheaper and better), and was released by Acorn in 1985. This was at the same time when Intel's technological miracle the 80386 processor appeared. ARM consisted of about ten times less transistors ( Read more... )

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Comments 20

anonymous November 22 2018, 12:15:26 UTC

Meynaf wrote on page 44 ( ... )

anonymous November 25 2018, 15:10:25 UTC

Just to reply about that "page 44" story ( ... )

anonymous November 26 2018, 06:38:21 UTC

ORRing addresses is not crazy on the ARM.
On the Archimedes it is the way you set the DMA addresses ;-)
https://books.google.fr/books?id=RkxnDwAAQBAJ&pg=PT121&lpg=PT121&dq=arm+memc+memory+bus&source=bl&ots=6wrL786biL&sig=3AJDM3K532mxk2qYGYENgUEY2RM&hl=fr&sa=X&ved=2ahUKEwjMiIv7uPHeAhVJXhoKHW5cDy8Q6AEwBXoECAIQAQ#v=onepage&q=arm%20memc%20memory%20bus&f=false

anonymous December 1 2018, 12:06:18 UTC

This is Archimedes/ARM specific. There is nothing like that on 68k machines.
Worse, on a multitasking machine like the Amiga, user program memory addresses change and logic operations are just meaningless (and the hardware does not need anything like that).

However it's true that ARM does not have a complex index addressing mode and this needs to be compensated somehow...

anonymous November 26 2018, 06:46:54 UTC

I couldn't post the link so use google with
arm memc memory bus

ORRing pointers on the ARM does make sense
for the Archimedes and RISC PCs etc ... to set the MEMC DMA values,
and the VIDC registers values too.
;-)

I have answered about ANDing addresses in the previous post,
and the benefits of building addresses for the PC, at will, with no constraint.

Try harder next time to state I don't know what I am talking about,
so far your comments make me burst out laughing.
Reading your BS on eab is like going to the zoo.

Thread 5

anonymous November 26 2018, 06:21:31 UTC

The answer given was very disappointing ( ... )

anonymous December 1 2018, 12:38:13 UTC

Ok, so your IF..OR..THEN is 12 bytes ( ... )