ld bc,-7 ;c=-7, b=0
Nope ... ld bc,-7 gives c=-7,b=255 (FFF9h)
Ah dang it haha yer right
To be frank, a better -readable- solution would be
LD BC,7
SUB A,C
#cleancode
LoL
Ld bc,f9h
Add a,c
#obscurecode
ld bc, +((-7 << 8) and $ff00) +(0 and $00ff) add c
#middlegroundcode 
I see no flickering. So you fixed it?
Yes, it's fixed. I change the tile layout in memory so I could copy them in a single operation (like you suggested) to this:
The green tiles at the beginning is where I copy the other tiles from RAM into VRAM. In groups of three per frame.
I also added halt just before update_tile() to smooth things out a bit (thanks, geijoenr). Most of the game loop is still in C so I am happy with the results.
#include
#include
extern const uint8_t map_data[MAP_WIDTH*MAP_HEIGHT];
uint8_t *map_data_p = map_data;
void run_loop() {
int8_t frame = -1;
bool game_running = true;
while (game_running) {
frame++;
__asm halt __endasm; // wait for vsync
update_tiles(); // move the maze up pixel by pixel by changing the pattern table
if (frame == 7) {
frame = -1; // reset frame counter
map_data_p += 32; // update map pointer by width size (point to the next line)
update_map(); // move the maze up tile by tile by changing the name table
}
// process user input and update sprites
// ...
wait(); // wait the allotted frame time to finish
} Login or register to post comments