Seingier François-Xavier wrote:

hello, I'm trying to understand how the initial stack works on a ppc4xx. According to start.S this is how the layout looks to me: ___________ | | | | | | | gd_t | |___________| | 0 | |___________| | 0 | |___________|<-+ | reset_vec | | SP ->|___________| | | |--+ |___________|<-+ | | | |___________| | | |--+ |___________| | ... |

I can't figure out precisely how the last stack frame works:

• /* clear final stack frame so that */

/* stack backtraces terminate cleanly */ I'm not sure to understand the "terminate cleanly".

Some debug tool that get confused ??

• why will the reset_vec be used in case of a stack underflow?

I tried to find an answer in the "PowerPC compiler writer's guide" about the ABI, but I am not even sure gcc uses an AIX or System V implementation...

You can not return from the first function but for some unknown reason you do that what should happen ?? a reboot is probably as good as anything.

The ABI for u-boot is eabi ftp://ftp.funet.fi/pub/mirrors/sourceware.cygnus.com/pub/binutils/ppc-docs/