Sparc / Leon, gdb, Oddball Window size, ecos, no backtrace

[John Carter <john dot carter at tait dot co dot nz>]

So we have a "sparc - a - like" leon embedded processor. (An
opensource VHDL sparc softcore)

For reasons of conserving gates on the FPGA, bless their smelly socks,
our custard logic blokes have implemented the sparc register windows
size as 7 instead of the more usual 8.

Now at some points in the code if you ask gdb for a backtrace, or to
go up a frame... gdb gets it's knickers in a knot and says you're at the
top most frame.

I believe it is not coping with the oddball window size.

Question :

1) Is there a gdb setting / work around for this?

2) Is there a gcc compiler optimization -fno-flag that would make
   gdb's life in this regard much easier? (Being an embedded of Very Little Ram, we are
   forced to compile -Os)

3) If I were to hack the gdb source to cope with this oddity... where
   should I start looking?

Thanks for your patience...



John Carter                             Phone : (64)(3) 358 6639
Tait Electronics                        Fax   : (64)(3) 359 4632
PO Box 1645 Christchurch                Email : john.carter@tait.co.nz
New Zealand