Re: RFA: addresses and pointers may be different sizes while printing

[David Taylor <taylor at candd dot org>]

    From: Jim Blandy <jimb@zwingli.cygnus.com>
    To: gdb-patches@sources.redhat.com
    Date: Thu, 28 Jun 2001 17:35:46 -0500 (EST)

    This is a preparatory patch for removing the D10V dependencies that
    have crept into the core of GDB (for example: value_at in valops.c).

    The D10V uses 16-bit pointers to index 256k code space.  Since all
    D10V instructions are 32 bits long, and naturally aligned, the PC is
    really 18 bits long, and the bottom two bits are always zero.  Within
    GDB, we model this by using 32-bit *addresses*, and converting
    *pointers* (which are 16 bits long) to *addresses* at the appropriate
    points.

    Without this conversion (which is necessary for some other
    architectures as well), the alternative is for GDB to think that
    pointers are 32 bits long, while the program being debugged thinks
    they're 16 bits long.  As you'd expect, chaos results.

    In any case, print_scalar_formatted assumes that pointers and the
    addresses they represent are the same length.  This isn't true for the
    D10V, so we need to remove that assumption.  That's what this patch is
    supposed to do.

    There are probably similar problems elsewhere, but we can fix them as
    we find them.  I found this one, so I'm fixing it.

    2001-06-28  Jim Blandy  <jimb@redhat.com>

	    * printcmd.c (print_scalar_formatted): If we are printing an
	    address, remember that TARGET_ADDR_BIT is not always equal to
	    TARGET_PTR_BIT.

Approved.