Arduino for STM32

Mispost

fpiSTM wrote: ↑Sun Jan 26, 2020 7:14 pm This is provided by ARM:
https://github.com/ARM-software/CMSIS_5 ... SP/Lib/GCC

Damm ...
".a" files ==> Compiled libraries

No source ..

Well i'd prob not understand the "magic" anyway

/Bingo

I had to .... Built F411 but as a cortex-m7 boards.txt :oops: GenF4.name=Generic STM32F4 series GenF4.build.vid=0x0483 GenF4.build.core=arduino GenF4.build.board=GenF4 GenF4.build.extra_flags=-D{build.product_line} {build.enable_usb} {build.xSerial} {build.bootloader_flags} #GenF4.build.mcu=cortex-m...

fpiSTM wrote: ↑Sun Jan 26, 2020 6:32 pm Maybe the cmsis library helps on this...

You mean this one ??
GenF4.build.cmsis_lib_gcc=arm_cortexM4lf_math

Seems like the F7 uses this one cmsis_lib_gcc=arm_cortexM7lfsp_math
Is the source available for those math libs ??

/Bingo

But according to the ARM or arm-gcc doc it is NOT wrong to specify -march=armv7e-m+fp. -mfloat-abi=hard -mfpu=fpv4-sp-d16 -fsingle-precision-constant We might have to add -mcpu=cortex-m4 to the above , in order confuse arm-gcc (thinking it's a cortex-m7) But unless someone "speculates" in ...

So the only difference between a m4 & a m7 is m4 = 3 stage pipeline & m7 = 6 stage pipeline.
m4 & m7 both can have an optional sp-fpu , and m7 can have an optional/additional dp-fpu.

/Bingo

Hmm, most realistic results are with -Os, imho. With -2, -3, you are getting results which are off my understanding :) https://gcc.gnu.org/onlinedocs/gcc-4.7.3/gcc/Optimize-Options.html -O -O1 Optimize. Optimizing compilation takes somewhat more time, and a lot more memory for a large function. Wit...

I would recommend to stay with -Os, as the higher levels may produce questionable results. Naah ... It's NOT -O2's fault i added -march=armv7e-m+fp . Actually it makes me wonder a bit why -mcpu=cortex-m4 didn't invoke -march=armv7e-m and -mfpu=fpv4-sp-d16 didn't add +fp automaticaly making it -marc...

Pito wrote: ↑Sun Jan 26, 2020 5:36 pm Some reading on D and W
http://users.ece.utexas.edu/~ljohn/teac ... eicker.pdf

So TRIG weights 21.6% , then a 3x would be +2x 21.6% = 43.2% extra
64,952×1,432 = 93,011264 ... And then a bit on the rest ... Would be close to ~ 100

/Bingo

The -mcpu=cortex-m4 -march=armv7e-m+fp Doesn't cut it w. the ST Core & PITO's program. I just did some "Stuff" in the ST Core .... with -mcpu=cortex-m4 -march=armv7e-m+fp -O2 ########################################## Single Precision C Whetstone Benchmark Calibrate 0.10 Seconds 1 Pass...