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

[Andrew Cagney <ac131313@redhat.com>]

>> +struct trad_frame

trad_frame_saved_regs?

>> +{
>> +  /* 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.

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

Nothing.

Andrew