Simplify (M - (n % M)) % M to M - (n % M), for n < 0.
#define XYOFFSET(x, y) (((y) * WORLD_X + (x)) / 2)
#define XNORM(x) \
- (((x) < 0) ? ((WORLD_X - (-(x) % WORLD_X)) % WORLD_X) : ((x) % WORLD_X))
+ (((x) < 0) ? (WORLD_X - (-(x) % WORLD_X)) : ((x) % WORLD_X))
#define YNORM(y) \
- (((y) < 0) ? ((WORLD_Y - (-(y) % WORLD_Y)) % WORLD_Y) : ((y) % WORLD_Y))
+ (((y) < 0) ? (WORLD_Y - (-(y) % WORLD_Y)) : ((y) % WORLD_Y))
struct range {
coord lx; /* low-range x,y */