Cordic trig assembly code for PIC18f

[Darrel Taylor]

Oh! It wasn't as hard as I thought it would be.

And yup, it's trying to pull the parameters off the stack, and would be overwriting the variables with random values from RAM.
I assume you've set those variables before calling the routine.

Commenting these should help...

  ; Set up the stack
;  movff FSR2L, POSTINC1
;  movff FSR1L, FSR2L


  ; Initialize _ang to passed parameter
;  movlw 0xfd
;  movff PLUSW2, _ang
;  movlw 0xfe
;  movff PLUSW2, _ang+1<hr>; Calculates the magnitude and direction of the given ordered pair
atan2_sqrt:

  ; Set up the stack
;  movff FSR2L, POSTINC1
;  movff FSR1L, FSR2L

  ; Initialize _x to passed parameter
;  movlw 0xfb
;  movff PLUSW2, _x
;  movlw 0xfc
;  movff PLUSW2, _x+1
;  movff POSTINC2, _x
;  movff POSTDEC2, _x+1

  ; Initialize _y to passed parameter
;  movlw 0xfd
;  movff PLUSW2, _y
;  movlw 0xfe
;  movff PLUSW2, _y+1
;  movlw 0x03
;  movff PLUSW2, _y+1
;  movlw 0x02
;  movff PLUSW2, _y

ADDED: OOPs, missed a couple ...

  ; Restore the stack to its previous state
;  movf POSTDEC1
;  movff INDF1, FSR2L

and there's another banksel atans in the as_loop_start: part.