meant of string "target sim ..."

[Formaggio Luca]

Hi. When I use the powerpc gdb I type a string
for target setup like this:

target sim -I -i -m 603 -o '/#address-cells 1' -o
'/openprom/init/register/pc 0x100' -o
'/iobus@0xf0000000/reg 0xf0000000 0x01000000' -o
'/iobus/pal@0xf0001000/reg 0xf0001000 32'

This string work very well but what is the meant of
various option of target sim? What is the meant of the
hex addresses?

Thanks
Luca Formaggio