14 Aug
2002
14 Aug
'02
5:25 p.m.
On Thu, 15 Aug 2002, Tony Duell wrote:
Our firmware is in assembler, the problem is what version of the
assembler, since the CPU may change daily... I do pretty well know the opcodes
in hex, ( I deliberately made add = AXXXXh, NOP = 0000h) but whenever I change
some bit field definition I forget what the machine code looks like anymore...
My CPU sort of looks like a pipelined 16 bit PIC so architecture wise
it dates from an on-topic time...
I used to remember most of the TMS9900 machine language (My first
Micro was a Technico 9900 based system, bought in 1976) because at first I
didnt have anything but a hex monitor to input programs with. Just found a
TI99/4 at the flea market for $2.00 so maybe I'll mess around a little with
9900 assembler again...
soorry for the ramble, past my bedtime.....
Actually it
can get worse... because you may well have your own (maybe buggy
and always changing) software tools for creating or debugging the firmware...
Well, I guess I'm way behind the times, as usual, but I still create my
microcontroller firmware in assembly language. And I _alway_ read the hex
file produced by the assembler and check that it really is a correct
assembly of the source code (I particularly check that labels have been
correctly interpretted, etc).
Sure it takes a bit of time to do that (but not as much as you might
think), but it does remove one possible source of problems.
-tony
Peter Wallace