Re: [Valgrind-developers] missing DFP guards ?

[Peter B. <be...@vn...>]

On Mon, 2015-09-14 at 09:03 -0700, Carl E. Love wrote:
On Sat, 2015-09-12 at 20:50 +0200, Florian Krohm wrote:
>> while looking at the vbit-test failure on ppc32 I noticed that in
>> guest_ppc_toIR.c all dis_dfp_XYZZY functions are guarded by
>>    if (!allow_DFP) goto decode_noDFP
>> except the two below. An oversight ?
> 
> Yes, this does appear to be an oversight as these instructions use an
> Iop that was created specifically for these instructions.  PPC32 does
> not have DFP support so trying to test the Iop on ppc32 would be an
> issue.

If by PPC32 you mean 32-bit hardware, then yes I know of no 32-bit
hardware that supports DFP.  OTOH, if by PPC32 you mean 32-bit
applications, then PPC32 DOES support DFP is that 32-bit application
is run on a POWER6 or later server hardware.  To really determine
if DFP is supported or not, you really should look at whether the
"dfp" flag is set in the AT_HWCAP.  The same is true of altivec,
vsx, etc.

[bergner@igoo ~]$ LD_SHOW_AUXV=1 /bin/true | grep AT_HWCAP
AT_HWCAP:        vsx arch_2_06 dfp ic_snoop smt mmu fpu altivec ppc64 ppc32


Peter