4 Oct
2006
4 Oct
'06
12:23 a.m.
hi Brantley,
Now I start to understand what's going on.
But do you mean 0744 by 0743?
0743 mov (sp), r0
0744 mov $_u, r0
And 2230 should be 2229, which is:
2229 sureg();
Thanks &
Regards,
Qinglai
On 10/3/06, Brantley Coile <brantley(a)coraid.com> wrote:
Rp->p_addr is the address of the swappable image in
core. The process
image begins with the user segment for that process. Line 0743 maps
the upage into the current address space (KISA6) and _retu loads
previously saved sp and r5 from there. Notice that on line 2230
Ken reloads the other memory mapping registers.
Read the section `Memory Management' starting on page 2-4 for background
on this.
U.u_rsave is just a constant location in memory. Notice that rp->p_addr
isn't a byte address but a core click address in units of 64 bytes.
Hope that helps.
Brantley
The final question is about how savu/retu work.
savu:
line 0729 and line 0730: r5 and sp are saved to (r0) and (r0)+, which
are the address of u.u_rsav.
retu:
0746 and 0747: sp and r5 are read from (r0) and (r0)+, which is
"rp->p_addr" (see line 2228). It looks weird to me. (Okay...I have to
confess I look stupid here...) When making call to retu, why bother
"retu(rp->p_addr)"? Why not calling with "retu(u.u_rsav)"? Does
it
mean that rp->p_addr == u.u_rsav?