math.h, how fast or slow?

[Nikki]

I'm using an 18F452.

Can it be right for math.h to take 11078 instructions to calculate cosine?

Inside "float cos(float x)", the line below costs just 1780 instructions.

quad = (int)(x / PI_DIV_BY_TWO); // quadrant

Is this expected?

It seems to be calculating correct values as I'm using these functions in graphics routines, but it's so sloooww.

Nikki
___________________________
This message was ported from CCS's old forum
Original Post ID: 144515490

[Haplo]

One way to work around the slowness of the Cos function is to set up a Cosine table in your program and then simply perform a table look-up whenever you need a Cos value.

Ali
___________________________
This message was ported from CCS's old forum
Original Post ID: 144515493

[Nikki]

:=One way to work around the slowness of the Cos function is to set up a Cosine table in your program and then simply perform a table look-up whenever you need a Cos value.

Thanks, I'm having a look at the CORDIC algorithm at the moment, though I'll probably go with a table.

Nikki
___________________________
This message was ported from CCS's old forum
Original Post ID: 144515497