RFR: aarch32: Another version of SoftFP implementation

[Sergey Nazarkin]

Hi Ed,

I’ve updated webrev  and introduce UseFPU variable 
http://cr.openjdk.java.net/~snazarki/softfp/src/cpu/aarch32/vm/globals_aarch32.hpp.sdiff.html
http://cr.openjdk.java.net/~snazarki/softfp/src/cpu/aarch32/vm/vm_version_aarch32.hpp.sdiff.html

BTW, RPI2 can be used to check same binary with FPU and FPU-less mode with single kernel substitution. 

Sergey Nazarkin




> On 26 Oct 2016, at 18:36, Edward Nevill <edward.nevill at gmail.com> wrote:
> 
> Hi Sergey,
> 
> I have tested this out on an armv7l platform and it seems to work fine.
> 
> The fact that it tests to see whether FPU is available is nice because
> it means we can build a single softfp image which will work on hardfp
> or softfp with minimal performance loss on hardfp.
> 
> It would be nice to have a -XX:+UseSoftFP for testing purposes as at
> the moment I have to rebuild forcing hasFPU() to false in order to test
> SoftFP (I don't have any non FPU hardware).
> 
> Looks ok to push.
> 
> yangyongyong: Do you have any comments?
> 
> All the best,
> Ed.
> 
> On Mon, 2016-10-24 at 17:12 +0000, Sergey Nazarkin wrote:
>> Hi!
>> 
>> Please review alternative version of SoftFP implementation
>> (Interpreter and C1) with VFP support in the soft-float binary[1]. In
>> contrast to [2] we keep assembler unchanged because we believe this
>> improve code readability. 
>> 
>> Another feature is java calling convention that is defined in runtime
>> and depends  on FPU availability. It may improve performance on
>> FPU/SoftFPABI platforms in comparison with traditional C-calling
>> convention. 
>> 
>> webrev: http://cr.openjdk.java.net/~snazarki/softfp/
>> 
>> [1] http://mail.openjdk.java.net/pipermail/aarch32-port-dev/2016-Octo
>> ber/000554.html
>> [2] http://mail.openjdk.java.net/pipermail/aarch32-port-dev/2016-Octo
>> ber/000546.html
>> 
>> Sergey Nazarkin
>> 
>> 
>> 
>>