equation optimization help -BPM calculations

[jsolarski 94]

(1000 / milliseconds) * 60 = BPM is the equation

 

 

is there a way to optimize this equation?

speed is not a factor since i have about 250ms to about 1000ms (250bpm to 60bpm) between beats

when i compile my program it adds A lot of code, about 140bytes, and i would like to get this down, because i still have to add display code and a few other calculations ( average time delay for 4 beats, and cycles to ms)

 

currently im just looking for some ideas, while i work on some of the other code

[oPossum 1,083]

BPM = 30000 / (milliseconds >> 1)

[jsolarski 94]

Looks like it save about 28bytes

 

Its a great start Thanks oPossum!!

[oPossum 1,083]

You could also try:

 

BPM = (unsigned)60000L / (unsigned)milliseconds;

 

Not 100% sure that will generate working code. CCS may not have unsigned / unsigned divide.

[gordon 229]

You could also try converting your calculations to use fixed point math, rather than floating (no, I don't actually know how to do that ).

[jsolarski 94]

Not 100% sure that will generate working code. CCS may not have unsigned / unsigned divide.

 

i dont know about ccs either since i use mspgcc, but i will try unsigned as well since i dont need signed integers

 

Edit: unsigned dropped it another 30 bytes or so

 

 

you could also try converting your calculations to use fixed point math

 

Im not using any floating points, like float or double, so it should be all fixed point

[oPossum 1,083]

ditto for MSPGCC and IAR. They may promote unsigned to long int, and make the code larger.

[ike 53]

BPM = 30000 / (milliseconds >> 1)

 

BPM = 15000 / (milliseconds >> 2)

BPM = 7500 / (milliseconds >> 3)

BPM = 3750 / (milliseconds >> 4)

BPM = 1875 / (milliseconds >> 5)

:roll: