Re: hf/sf [Was Re: CVS commit: pkgsrc/misc/raspberrypi-userland]

[mlelstv%serpens.de@localhost (Michael van Elst)]

justin%specialbusservice.com@localhost (Justin Cormack) writes:

>On Mon, Nov 11, 2013 at 10:56 PM, Michael van Elst 
><mlelstv%serpens.de@localhost> wrote:
>> matt%3am-software.com@localhost (Matt Thomas) writes:
>>
>>>Exactly.  with hf, floating point values are passed in floating point
>>>registers.  That can not be hidden via a library (this works on x86
>>>since the stack has all the arguments).
>>
>> It could be hidden by emulating the floating point hardware.

>Thats not sane. The slowdown would be enormous. You are emulating
>registers as well as operations.


The "slowdown" is already enormous due to lack of floating point
hardware. That's why emulating the FP hardware is a very common
way to handle this situation, just look at the other platforms.

The rationale behind this is, that people who use FP operations
in any significant way will use hardware that supports it. And
others will hardly notice the extra slowdown cause by emulation.

The questions are: does ARM support this and is there a usuable
implementation. Linux dropped NWFPE due to licensing issues.