17 Dec
2012
17 Dec
'12
4:19 p.m.
On 12/17/2012 2:26 PM, Mouse wrote:
it's not much help, because the code at 3ab7 ends
up
calling through a run-time-set pointer:
I am totally unprepared to help, but when
we had problems like this we
had to code up small runtime routines to scan the memory space for what
were JMP and JMP indirect instructions in our Microdata 1621 object code
to find out who was connected to what.
Maybe if holme had such a routine he could run it and find the runtime
setup ones. Or maybe if one is lucky, the code you have at 0x04c8 is a
table and could just be dumped to continue the hunt.
Also hopefully there are not more layers between the printf and the
output routines. At least once you find the output side and the
registers, you can then possibly scan for the register references if you
are lucky and find the input character or string code.
Did this version of uart possibly have buffering and DMA, or was it
interrupt char / char most likely. Impossibly to know w/o finding it of
course. Now days most serial devices I find even for consoles have DMA
and buffering that makes the deciphering and subsequent coding of quite
difficult. Happily I've not had to do so, and the code is open and
quite available now days.
Jim