about using math

[tinhaode]

hello!
I would like to use some of math related function calls like pow, sin, sqrt...
But it seems math function doesn't work with SDK.
Either #include<math.h> on user_main or -lm on the Linker doesn't work too.
Do you have any idea to work them out?

[AgentSmithers]

That's funny. I was just reading this today.
http://moishelettvin.blogspot.com/2005/ ... posed.html

Indirectly it may relate to your question.

[tinhaode]

sorry I can't open the url. could you copy some word?

[AgentSmithers]

sorry I can't open the url. could you copy some word?

What math functions would you like, How fast do they need to be?

Functions like Sin I think is 1 = x^2 + y^2 so I think if you take an argument you just do 1 - (arg)^2 = Value then SquareRoot that I think. Sorry I took trig like a year ago and it's already gone XD

[Pato]

Hey,

@AgentSmithers: Indeed a kind of last resort solution would be to re-write the math functions (e.g. with Taylors series approximations, it's in the idea of what you proposed )

@tinhaode: did you managed to fin a solution ? I'm also trying to experiment with math functions, but I got linker errors. Maybe try using the limirom.a from the RTOS_SDK, it seemed to work for some folks...
https://bbs.espressif.com/viewtopic.php ... math#p3215
(failed with same error for me. I use a custom toolchain inspired from esp-open-sdk)

[Pato]

It may help, I was able to link against the math lib after some tweaking:

https://bbs.espressif.com/viewtopic.php?f=7&t=9432

[andreysnug]

You could use GetAsyncKeyState from windows.h to detect key presses and program your own macros using SendInput.