Re: [Qemu-devel] [PATCH 1/4] SPARC64: Implement ldfa/lddfa/ldqfa instructions properly

[Artyom Tarasenko]

On Wed, Jul 13, 2011 at 6:27 PM, Blue Swirl <address@hidden> wrote:
> On Wed, Jul 13, 2011 at 6:30 AM, Tsuneo Saito <address@hidden> wrote:
>> This patch implements sparcv9 ldfa/lddfa/ldqfa instructions
>> with non block-load ASIs.
>>
>> Signed-off-by: Tsuneo Saito <address@hidden>
>> ---
>>  target-sparc/op_helper.c |   16 +++++++++++-----
>>  1 files changed, 11 insertions(+), 5 deletions(-)
>>
>> diff --git a/target-sparc/op_helper.c b/target-sparc/op_helper.c
>> index fd0cfbd..a75ac4f 100644
>> --- a/target-sparc/op_helper.c
>> +++ b/target-sparc/op_helper.c
>> @@ -3331,7 +3331,7 @@ void helper_ldda_asi(target_ulong addr, int asi, int 
>> rd)
>>  void helper_ldf_asi(target_ulong addr, int asi, int size, int rd)
>>  {
>>     unsigned int i;
>> -    target_ulong val;
>> +    CPU_DoubleU u;
>>
>>     helper_check_align(addr, 3);
>>     addr = asi_address_mask(env, asi, addr);
>> @@ -3371,17 +3371,23 @@ void helper_ldf_asi(target_ulong addr, int asi, int 
>> size, int rd)
>>         break;
>>     }
>>
>> -    val = helper_ld_asi(addr, asi, size, 0);
>>     switch(size) {
>>     default:
>>     case 4:
>> -        *((uint32_t *)&env->fpr[rd]) = val;
>> +        *((uint32_t *)&env->fpr[rd]) = helper_ld_asi(addr, asi, size, 0);
>>         break;
>>     case 8:
>> -        *((int64_t *)&DT0) = val;
>> +        u.ll = helper_ld_asi(addr, asi, size, 0);
>> +        *((uint32_t *)&env->fpr[rd++]) = u.l.upper;
>> +        *((uint32_t *)&env->fpr[rd++]) = u.l.lower;
>>         break;
>>     case 16:
>> -        // XXX
>> +        u.ll = helper_ld_asi(addr, asi, 8, 0);
>> +        *((uint32_t *)&env->fpr[rd++]) = u.l.upper;
>> +        *((uint32_t *)&env->fpr[rd++]) = u.l.lower;
>> +        u.ll = helper_ld_asi(addr + 8, asi, 8, 0);
>
> In general the patch is an improvement, however the ASIs are passed as
> is to helper_ld_asi() and there the block ASIs would trigger
> unassigned access faults.

You mean the not [yet] implemented block ASIs? The implemented ones
return earlier
and for the not implemented ones unassigned access fault appears to be
a right thing to do.
Do you have an example where we would have an unassigned access fault
for an implemented ASI ?

>So you should perform some arithmetic with
> the ASI numbers to make them match non-block ASIs, for example asi &
> ~0x6. This only works in the specific block ASIs, so I'd move this
> inside the switch block for cases 0x16, 0x17, 0x1e, 0x1f etc. By the
> way, aren't those the ASIs in question? The manual (UltraSPARC
> Architecture 2007) is a bit confusing.
>
>> +        *((uint32_t *)&env->fpr[rd++]) = u.l.upper;
>> +        *((uint32_t *)&env->fpr[rd++]) = u.l.lower;
>>         break;
>>     }
>>  }
>> --
>> 1.7.5.4
>>



-- 
Regards,
Artyom Tarasenko

solaris/sparc under qemu blog: http://tyom.blogspot.com/