RFR: aarch32: Another version of SoftFP implementation

[Edward Nevill]

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
> 
> 
> 
>