Re: [Qemu-devel] [PATCH] sh4: define explicitly that the target CPU is 32 bit

[Carlo Marcelo Arenas Belon <carenas@sajinet.com.pe>]

On Fri, Nov 30, 2007 at 04:28:09PM +0000, Paul Brook wrote:
> On Friday 30 November 2007, Carlo Marcelo Arenas Belon wrote:
> > The following patch enforces that the sh4 target is 32 bit to prevent qemu
> > to expand incorrectly to a 64 bit wide cpu if compiled in a 64 bit host.
> 
> This is wrong. As the comment in cpu-defs.h says, target_phys_addr_t may need 
> to be bigger than the actual target address space.
> 
> What exactly are you trying to fix?

in a generic way, that the CPU width of the host (as defined by the size of
the type that is used to store a target_phys_addr_t) that is used to build 
the emulator affects in any way the size of the emulated target physical 
address size or its representation.

in the sh4 specific case, it doesn't make sense for sh4 to print an access
error to a physical address that is 64 bit long when it is a 32 bit CPU and
that is what would happen unless the patch is applied.

if anything the following definition from cpu-defs.h is invalid for a
representation of a 32 bit physical address :

#define TARGET_FMT_plx "%016" PRIx64

Carlo