Am 22.07.2013 19:27, schrieb Peter Maydell: > On 22 July 2013 17:36, Andreas Färber <afaer...@suse.de> wrote: >> Signed-off-by: Andreas Färber <afaer...@suse.de> >> --- >> HACKING | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/HACKING b/HACKING >> index e73ac79..d9dbb46 100644 >> --- a/HACKING >> +++ b/HACKING >> @@ -42,6 +42,7 @@ ram_addr_t. >> >> Use target_ulong (or abi_ulong) for CPU virtual addresses, however >> devices should not need to use target_ulong. >> +Use vaddr for CPU virtual addresses in target-independent code. > > Here's my suggestion for this paragraph (ie to replace > both the "Use target_ulong..." and "Use vaddr" sentences > above): > > ===begin=== > For CPU virtual addresses there are several possible types. > vaddr is the best type to use to hold a CPU virtual address > in target-independent code, including most devices. It is
Thanks. What reason can you think of for using vaddr in a device? Andreas > guaranteed to be large enough to hold a virtual address for > any target, and it does not change size from target to target. > It is always unsigned. > target_ulong is a type the size of a virtual address on the CPU; > this means it may be 32 or 64 bits depending on which target > is being built. It should therefore be used only in target > specific code, and in some performance-critical built-per-target > core code such as the TLB code. There is also a signed version, > target_long. > abi_ulong is for the *-user targets, and represents a type the > size of 'void *' in that target's ABI. (This may not be the same > as the size of a full CPU virtual address in the case of target > ABIs which use 32 bit pointers on 64 bit CPUs, like sparc32plus.) > Definitions of structures that must match the target's ABI > must use this type for anything that on the target is defined > to be an 'unsigned long' or a pointer type. There is also a > signed version, abi_long. > ===endit=== > > (cc'ing Paolo to check I didn't mangle the abi_ulong/target_ulong > distinction.) > > thanks > -- PMM > -- SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
