6 Jan
2006
6 Jan
'06
8:20 a.m.
Eric J Korpela wrote:
On 1/3/06, Chuck Guzis <cclist at sydex.com>
wrote:
Instruction set does no longer matter since microcontrollers come with
flash ROMs of 1MB size or larger, and are programmed in C or even BASIC
(with a builtin interpreter or a cross compiler).
I liked the PDP-11 instruction set (as well as 6809/68000 sets) very
much, but they were made mainly for assembler freaks - no worrying about
where to put data or addresses - basically every register worked with
every instruction type or address mode. In contrast, instruction sets
for processors like 8080/Z80/8086, where specialized registers exist
(like HL, or CX, or SI/DI) and special instructions that don't work only
under specific data layout conditions.
These times are gone - assembler is irrelevant for larger projects, and
controller have become large enough to allow wasting space and tolerate
inefficient code.
Some controllers, including the rather lousy 8051 series, still persist,
but mainly because "system designers" have used and understood them for
20 years now and it is too expensive to train them another horse.
Holger
Yet, the reverse has turned out to be true--the
68HC11
seems to be everywhere--and the 6502 has been pretty much relegated to
obscurity after some popularity in the first generation of personal
computers.
Which leads me, in a way, to the conclusion that
maybe instruction sets
don't matter all that much in the real world.
I've been wondering about this as well. I would have assumed that for
microcontrollers that cost would be supreme. Did the 6800 family get
cheaper than the 6502 at some point? After all saving a dollar a unit
on 100K units pays for a programmer.