[U-Boot-Users] how does stack work?
Kenneth Johansson
kenneth.c.johansson at ericsson.com
Tue Jul 27 19:31:46 CEST 2004
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/
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