maybe a config issue , there is not much i can see that would not work in the asm stuff unless the 8x8 mult works differently


you could try this , clutching at straws
the code just assumes bank0

Code:
atan2_sqrt:
  banksel 0
  ; Initialize _ang to 0
  clrf _ang
  clrf _ang+1
.......

Code:
sin_cos:
 banksel 0
  ; Initialize _x to 18218
  movlw 0x2a
  movwf _x
  movlw 0x47
  movwf _x+1
...............