what is the fastest way to convert signed int16 to 7-segment

40inD · Joined: 30 Jul 2007 Posts: 112 Location: Moscow, Russia

What is the fastest way to convert signed int16 (from -99 to 999) into 3 digit 7-segment appearance (including Minus sign)?

Ttelmah · Joined: 11 Mar 2010 Posts: 19454

Probably nothing too much better than the standard functions.
However it should be fractionally faster, to test for -ve, display the sign, convert to +ve, and handle as unsigned. Then all the divisions can be done with unsigned arithmetic. Then the ldiv function is the most efficient way to handle the /10's, since this gives quotient and remainder directly.
I'd suspect using this approach you could probably beat the standard operation noticeably.

Best Wishes

40inD · Joined: 30 Jul 2007 Posts: 112 Location: Moscow, Russia

Something like this?

Ttelmah · Joined: 11 Mar 2010 Posts: 19454

Nearly.
Remember though you need to test for the value being -ve first, and if it is, display the -, and change the sign of the value.

Try timing it with the stopwatch in MPLAB, and see how it compares with the standard version.

Also, are you happy to have the leading zeros displayed?. If not, you'll need to test for these and blank them. and (of course) you'dd need to make sure the value can't go outside the range.

Best Wishes