How to safely and reasonably convert a float or double to string or char array?

Projects Programming
50

@westfw

I have actually looked it up. Please correct me if I am wrong:

printf is basically a call to vfprintf and vfprintf has both assembly and __ftoa_engine usage.
Which means I go back to the same place where I started.

printf: https://sourcecodebrowser.com/avr-libc/1.8.0/group__avr__stdio.html#ga4c04da4953607fa5fa4d3908fecde449

vfprintf: https://sourcecodebrowser.com/avr-libc/1.8.0/group__avr__stdio.html#gaa3b98c0d17b35642c0f3e4649092b9f1

I do not have too much experience with AVR assembly and considering the IDE support for assembly I gave up on that immediately.

I read more about Dragon and Grisu and I think it is a lot more complex than what we need in Arduino. They have actually introduced new data types of up to 35 uint32_t array (for 64 bit float). It is very precious but I do not think we can afford that much processing for dtostrf. The solution in second link is slightly better because it is based on itoa and therefore I have to do less work to come up with a new dtosrf and bigger part of it has been tested.

Honestly deep inside I wish I could use __ftoa_engine(), because then everything would be supper easy. sigh.