04-11-2019, 10:10 AM
Hi all!
I like to build small RPN calculators (ScArY, SCOTT, ARC) with AVR microcontrollers (which are easy to program).
Unfortunately these microcontrollers support float numbers with 4 byte single precision (due IEEE-754) only. That means they support a precision of 6 to 7 decimal digits.
Now I would like to improve this precision to at least 9 decimal digits. The only idea I have is to define a new number format (struct) to separate mantissa and exponent:
But now I have to "reinvent" every mathematical operation like adding two numbers (the following code works, but is far from beeing efficient):
Looking forward to transzendent functions or complex numbers I feel overstrained.
Do you have any other idea how to raise the precision with less effort?
Thanks for any idea.
deetee
I like to build small RPN calculators (ScArY, SCOTT, ARC) with AVR microcontrollers (which are easy to program).
Unfortunately these microcontrollers support float numbers with 4 byte single precision (due IEEE-754) only. That means they support a precision of 6 to 7 decimal digits.
Now I would like to improve this precision to at least 9 decimal digits. The only idea I have is to define a new number format (struct) to separate mantissa and exponent:
Code:
struct real {
long m;
int8_t e;
};
But now I have to "reinvent" every mathematical operation like adding two numbers (the following code works, but is far from beeing efficient):
Code:
void realadd(real * res, real a, real b) {
if (a.e >= b.e) {
b.m /= _pow10(a.e-b.e);
res->m = a.m + b.m;
res->e = a.e;
}
else {
a.m /= _pow10(b.e-a.e);
res->m = a.m + b.m;
res->e = b.e;
}
}
Looking forward to transzendent functions or complex numbers I feel overstrained.
Do you have any other idea how to raise the precision with less effort?
Thanks for any idea.
deetee