parallel port debugging, need cyclic function call

[Torsten Mohr <tmohr at s dot netic dot de>]

Hi,

i made a new version of a parallel port project available at:

http://www.s.netic.de/tmohr/pppcb-0.3.0.tar.gz

With that library you can debug an ARM7TDMI via the
parallel port.  Now also HW breakpoints and single
stepping is supported.

At the moment i try to port its functionality to gdb-5.3.

I've yet added:

pport.h: function prototypes

pport_linux.c:
write data and control register, read status
register, lowlevel intialisation, set device name,
machine-specific delay routines


pport_common.c:
provide setting an "inversion mask" for parallel
ports registers, set/clear/read single pins.
Some examples:
"pport invdata 0x02" inverts D1 of the parallel port.
"pport high 5" sets D5 to high level.
"pport low 3" sets D3 level to low.
"pport read 23" reads the BUSY line of the status register.


ppjtag.c:
provide software JTAG over the parallel ports pins.
What pins have what functionality can be set with
commands like.  The delay can also be set.
Some examples:
"ppjtag tms 3" tells the SW JTAG to use D3 as "Test Mode Set".
"ppjtag delay 3" sets a delay of 3 useconds.


ppja.c: (Parallel Port Jtag Arm, stupid name)
All the functionality to debug an ARM via the parallel port.
Examples:
"ppja info" prints the IDCODE of the attached target.


There isn't yet much working, i'm trying to give gdb
a "struct target_ops *" to tell it how to use the
functionality.

Is there an entry in "struct target_ops" that is called
cyclically?  I need to check from time to time, if the
targets state has changed.  "target.h" is quite useful,
but i didn't find any functionality like that in it.


Is there a way to tell gdb to cyclically call a certain
function?


Best regards,
Torsten.