>>195 こんなカンジ?

#define CHIP_SIZE_X 32
#define CHIP_SIZE_Y 32
#define MAP_SIZE_X 20
#define MAP_SIZE_Y 15
#define SCREEN_SIZE_X 640

int MapData[MAP_SIZE_Y][MAP_SIZE_X];

void DrawMap(int offset_x)
{
  int x1, x2, y;

  x1 = (offset_x/CHIP_SIZE_X)%MAP_SIZE_X;
  x2 = -(offset_x%CHIP_SIZE_X);
  while (x2 < SCREEN_SIZE_X) {
    for (y = 0;y < MAP_SIZE_Y;++y) {
      DrawMapChip(x2, y*CHIP_SIZE_Y, MapData[y][x]);
    }
    x2 += CHIP_SIZE_X;
    x1 = (x1+1)%MAP_SIZE_X;
  }
}