🚀 go-pugleaf

I am engaged in porting gdb to the Ncube series of processors.  So far,
everything is generally going well.  Here is a probable bug I believe I have
discovered in the portable code.

On Ncube, all registers are 64 bits.  The machine uses BYTES_BIG_ENDIAN and
WORDS_LITTLE_ENDIAN.  The bug arises when I ask gdb to print an "int" automatic
variable which just happens to be in a register.  value_from_regiser() offsets
incorrectly into the virtual_buffer holding the register bytes .

Note the bug would not surface if the machine were WORDS_BIG_ENDIAN which is
why it does not happen on the convex port.  Incidentally, gcc defines convex
to be WORDS_LITTLE_ENDIAN which is inconsistent from the way gdb defines
things.  I do not know who is right.

thanks
--bill

===================================================================
RCS file: /rcs/cvs/gnu/gdb/findvar.c,v
retrieving revision 1.1.1.1
diff -c -r1.1.1.1 findvar.c
*** /tmp/,RCSt1a00174   Tue Jun  5 14:41:45 1990
--- findvar.c   Tue Jun  5 14:22:03 1990
***************
*** 484,495 ****
        /* Raw and virtual formats are the same for this register.  */

  #ifdef BYTES_BIG_ENDIAN
        if (len < REGISTER_RAW_SIZE (regnum))
        {
          /* Big-endian, and we want less than full size.  */
          VALUE_OFFSET (v) = REGISTER_RAW_SIZE (regnum) - len;
        }
! #endif

        bcopy (virtual_buffer + VALUE_OFFSET (v),
             VALUE_CONTENTS (v), len);
--- 484,503 ----
        /* Raw and virtual formats are the same for this register.  */

  #ifdef BYTES_BIG_ENDIAN
+ #  ifdef WORDS_BIG_ENDIAN
        if (len < REGISTER_RAW_SIZE (regnum))
        {
          /* Big-endian, and we want less than full size.  */
          VALUE_OFFSET (v) = REGISTER_RAW_SIZE (regnum) - len;
        }
! #  else
!       if (len < REGISTER_RAW_SIZE (regnum) && len < sizeof (long))
!       {
!         /* Big-endian, and we want less than full size.  */
!         VALUE_OFFSET (v) = sizeof (long) - len;
!       }
! #  endif /* WORDS_BIG_ENDIAN */
! #endif /* BYTES_BIG_ENDIAN */

        bcopy (virtual_buffer + VALUE_OFFSET (v),
             VALUE_CONTENTS (v), len);