Integer Arithmetic Assistance Required

[HenrikOlsson]

Hi,
One possible solution

Dummy VAR WORD

Dummy = Red * Pot4
ScaledRed = DIV32 1024

Dummy = Green * Pot4
ScaledGreen = DIV32 1024

Dummy = Blue * Pot4
ScaledBlue = DIV32 1024

/Henrik.

[Aussie Barry]

Hi Henrik,

I knew there had to be a simple way of doing this, I just couldn't figure it out on my own - thank you!
Will the DIV32 command be affected if I am using DT-Interrupts? What happens is an interrupt occurs between the two arithmetic operations?
Dummy = Red * Pot4
Interrupt occurs here
ScaledRed = DIV32 1024

Cheers
Barry
VK2XBP

[HenrikOlsson]

It shouldn't have any effect. DT-INTS saves the system variables when entering the ISR so even if an interrupt happens in between the multiplication and the division AND the ISR happens to use the same system variables (R0 and R2 IIRC) holding the 32 bit result from the multiplication no harm is done since the content of those variables are restored by DT-INTS when exiting the ISR.

/Henrik.

[Aussie Barry]

Hi Henrik,

The DIV32 approach worked perfectly - thank you.

Cheers
Barry
VK2XBP