Re: [RFA] Functionalize registers[] and register_valid[]

[Eli Zaretskii <eliz at delorie dot com>]

> Date: Wed, 3 Jan 2001 15:42:32 -0500
> From: Nicholas Duffek <nsd@redhat.com>
> 
> This patch is in preparation for the new register definition interface
> patch following this message.  It applies over the regno/regnum regcache.c
> patch I posted earlier.
> 
> The patch replaces certain constructs with function calls, as follows:
> 
>   1. "register_valid[regnum]" becomes "register_cached (regnum)" or
>      "set_register_cached (regnum)".
> 
>   2. "registers[regnum]" becomes "register_buffer (regnum)".
> 
>   3. "registers" becomes "register_buffer (-1)".
> 
>   4. "regnum < NUM_REGS" becomes "real_register (regnum)".
> 
>   5. The sequence:
> 
>        if (real_register (regnum))
>          target_fetch_registers (regnum);
>        else if (pseudo_register (regnum))
>          FETCH_PSEUDO_REGISTER (regnum);
> 
>      becomes "fetch_register (regnum)".  This fixes a bug where
>      read_signed_register() would fail given a pseudo-register.
> 
>   6. The sequence:
> 
>        if (real_register (regnum))
>          target_store_registers (regnum);
>        else if (pseudo_register (regnum))
>          STORE_PSEUDO_REGISTER (regnum);
> 
>      becomes "store_register (regnum)".
> 
> The next patch will modify the new functions to call into the new register
> definition interface if it's active.

Is this change guaranteed to be 100% backward-compatible?  That is,
will the old code still work?  (From a quick look at the diffs, it
seems so, but I'm not sure I didn't miss something.)

If not, it will need to be accompanied by approriate changes to all
the application-level and target-specific code which currently uses
the old interface, or else that code will break.