This intro shows simplified CORDIC algorithm
intended for computing size of two-dimensed vector.
It is based on 8 byte routine from CORDIC demo 8
but the addtional preface is added to serve
the case of X < Y.
In this case, X and Y are swapped :)
Source code:
Input: C = coordinate X
B = coordinate Y
Output: C = result = SQR(X^2+Y^2)
ld a,c
cp b
jr nc,L1
ld c,b
ld b,a
ld a,c
L1: sub b
jr nc,L2
inc c
add c
L2: djnz L1
Now whole routine takes 14 bytes length.
The condition X >= Y disappeared, but all next conditions are still valid:
(X^2+Y^2) < 65536 ... Since result is 8 bit only, we must make sure to not produce overflow
X > 0 ........\____ Any coordinate can be zero (then result is directly another coordinate)
Y > 0 ......../ but due to using DJNZ, zero means 256 iterations and it is still not good.
