Re: [Qemu-devel] [PATCH v1] s390x/tcg: Don't model FP registers as globals

[David Hildenbrand <david@redhat.com>]

On 04.02.19 14:27, Richard Henderson wrote:
> On 1/31/19 2:37 PM, David Hildenbrand wrote:
>> As floating point registers overlay some vector registers and we want
>> to make use of the general tcg_gvec infrastructure that assumes vectors
>> are not stored in globals but in memory, don't model flaoting point
>> registers as globals anymore. This is than similar to how arm handles
>> it.
>>
>> Reading/writing a floating point register means reading/writing memory now.
>>
>> Break up ugly in2_x2() handling that modifies both, in1 and in2 into
>> in1_x2l and in2_x2h. This makes things more readable. Also, in1_x1() is
>> ugly as it touches out/out2, get rid of that and use prep_x1() instead.
>>
>> As we are no longer able to use the original global variables for
>> out/out2, we have to use new temporary variables and write from them to
>> the target registers using wout_ helpers.
>>
>> E.g. an instruction that reads and writes x1 will use
>> - prep_x1 to get the values into out/out2
>> - wout_x1 to write the values from out/out2
>> This special handling is needed for x1 as it is often used along with
>> other inputs, so in1/in2 is already used.
>>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
>> ---
>>  target/s390x/insn-data.def | 150 ++++++++++++++++++-------------------
>>  target/s390x/translate.c   | 133 +++++++++++++++++++-------------
>>  2 files changed, 158 insertions(+), 125 deletions(-)
> 
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

Thanks!

I'll probably switch naming of in1_x2l and in2_x2h to

in1_x2h and in2_x2l (will double check, but I guess this is the right
thing to do - high double word always comes first, e.g. in memory).

> 
> 
> r~
> 


-- 

Thanks,

David / dhildenb