[fpc-devel] What is the best match for for -mfpu=fpv4-sp-d16 on fpc-arm?

[Florian Klämpfl]

Am 11.04.20 um 22:13 schrieb Michael Ring via fpc-devel:
> I found this reference manual for floating point instructions:
> 
> https://www.st.com/resource/en/programming_manual/dm00046982-stm32-cortexm4-mcus-and-mpus-programming-manual-stmicroelectronics.pdf
> 
> and this high level overview:
> 
> https://embeddedartistry.com/blog/2017/10/11/demystifying-arm-floating-point-compiler-options/
> 
> What is funny is that I did not find FPV4_S16 in the link above, only 
> *VFPv4-D32,**VFPv4-D16 and ***VFPv4U**

It is probably what Cortex-M4 needs. However, it does not seem to be 
completely correct. I'll add fpv4-sp-d16 (it means: single precision 
only with 32 registers, but for load/store/move they can be considered 
as 16 double registers) and fix everything