[fpc-devel] ARM: problem with uses VFP instructions

Jonas Maebe jonas.maebe at elis.ugent.be
Wed Dec 2 15:41:38 CET 2009

On 02 Dec 2009, at 15:17, Dariusz Mazur wrote:

>   *
>     __VFP_FP__ means that the floating point format in use is that of
>     the ARM VFP unit, which is native-endian IEEE-754.
>   *
>     __MAVERICK__ means that the floating point format is that of the
>     irrus Logic MaverickCrunch
>     <http://wiki.debian.org/MaverickCrunch>, which is also IEEE-754
>     and is always little-endian.
>   *
>     __SOFTFP__ means that instead of floating point instructions,
>     library calls are being generated for floating point math
>     operations so that the code will run on a processor without an  
> FPU.
> __VFP_FP__ and __MAVERICK__ are mutually exclusive. If neither is  
> set, that means the floating point format in use is the old mixed- 
> endian 45670123 format of the FPA unit.
> Note that __VFP_FP__ does /not/ mean that VFP code generation has  
> been selected. It only speaks of the floating point data format in  
> use and is normally set when softfloat has been selected. The  
> correct test for VFP code generation, for example around asm  
> fragments containing VFP instructions, is
> My question is: which variant use FPC

By default, on ARM/EABI FPC uses native-endian IEEE-754, but uses  
library calls (to internal code in the RTL) to emulate the floating  
point operations. So it's a combination of __VFP_FP__ and __SOFTFP__.


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