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Update some comments.

This commit is contained in:
skrll 2008-01-25 12:35:48 +00:00
parent ebb5deb738
commit 572591cbe8
1 changed files with 12 additions and 11 deletions
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23
gnu/dist/gdb6/gdb/i386nbsd-nat.c vendored
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@ -44,22 +44,22 @@ i386nbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
/* The following is true for NetBSD 1.6.2 and after:
The pcb contains %esp and %ebp at the point of the context switch
in cpu_switch(). At that point we have a stack frame as
described by `struct switchframe', which for NetBSD has the
following layout:
in cpu_switch()/cpu_switchto(). At that point we have a stack frame as
described by `struct switchframe', which for NetBSD (2.0 and later) has
the following layout:
interrupt level
%edi
%esi
%ebx
return address
we reconstruct the register state as it would look when we just
returned from cpu_switch().
returned from cpu_switch()/cpu_switchto().
For core dumps the pcb is saved by savectx() and contains the
stack pointer and frame pointer. In this case extract a return
address from the stack. */
For core dumps the pcb is saved by savectx()/dumpsys() and contains the
stack pointer and frame pointer. A new dumpsys() fakes a switchframe
whereas older code isn't reliable so use an iffy heuristic to detect this
and use the frame pointer to recover enough state. */
/* The stack pointer shouldn't be zero. */
if (pcb->pcb_esp == 0)
@ -69,7 +69,8 @@ i386nbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
if ( (unsigned long)sf.sf_eip >= (unsigned long)0xc0100000 )
{
/* Yes, we have a frame that matches cpu_switch(). */
/* Yes, we have a switchframe that matches cpu_switchto() or
the new dumpsys(). */
pcb->pcb_esp += sizeof (struct switchframe);
regcache_raw_supply (regcache, I386_EDI_REGNUM, &sf.sf_edi);
@ -83,8 +84,8 @@ i386nbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
{
CORE_ADDR pc, fp;
/* No, the pcb must have been last updated by savectx() in
dumpsys. Use the frame pointer to recover enough state. */
/* No, the pcb must have been last updated by savectx() in old
dumpsys(). Use the frame pointer to recover enough state. */
read_memory (pcb->pcb_ebp, (gdb_byte *) &fp, sizeof(fp));
read_memory (pcb->pcb_ebp + 4, (gdb_byte *) &pc, sizeof(pc));