Re: [commit] Split d10v-tdep.c into trad-frame.[hc]

[Daniel Jacobowitz <drow at mvista dot com>]

On Sun, Jun 08, 2003 at 01:45:06PM -0400, Andrew Cagney wrote:
> 
> >>+struct trad_frame
> 
> trad_frame_saved_regs?

trad_frame_saved_reg?  Even if you'll only ever use this as an array,
the structure is a singular register.

> >>+{
> >>+  /* If non-zero (and regnum >= 0), the stack address at which the
> >>+     register is saved.  By default, it is assumed that the register
> >>+     was not saved (addr == 0).  Remember, a LONGEST can always fit a
> >>+     CORE_ADDR.  */
> >>+  LONGEST addr;
> >>+  /* else, if regnum >=0 (and addr == 0), the REGNUM that contains
> >>+     this registers value.  By default, it is assumed that the
> >>+     registers are not moved (the register's value is still in that
> >>+     register and regnum == the index).  */
> >>+  int regnum;
> >>+  /* else, if regnum < 0, ADDR is the registers value.  */
> >>+};
> >
> >
> >Gyuh?  I looked at this for a couple of minutes and couldn't make heads
> >or tails of it until I went to look at trad-frame.c: this structure
> >isn't a frame at all, it's a single saved register.  Could you rename
> >it, and update the comments?
> >
> >I'm also not sure I understand all the combinations:
> >  regnum < 0, addr is the register value
> >  regnum >= 0 and addr 0, regnum holds the new register number (in the
> >    next frame?)
> 
> The previous frame's register is found in REGNUM in this frame.  Need to 
> unwind the next frame's REGNUM to get the value of register REGNUM in 
> this frame.

The third REGNUM there means the array index, not the REGNUM member,
right?

> >  regnum >= 0 and addr non-zero, addr is the save address - but what's
> >    regnum mean?  Nothing?
> 
> Nothing.

OK, I see.  I'd appreciate it if you clarified that in the comment.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer