36 lines
797 B
C
36 lines
797 B
C
#include <screen.h>
|
|
|
|
/*
|
|
screen_display()
|
|
|
|
Displays the given vram on the screen. Only bytes can be transferred
|
|
through the screen registers, which is unfortunate because most of the
|
|
vram-related operations use longword-base operations.
|
|
*/
|
|
void screen_display(const void *ptr)
|
|
{
|
|
const char *vram = (const char *)ptr;
|
|
volatile char *selector = (char *)0xb4000000;
|
|
volatile char *data = (char *)0xb4010000;
|
|
int line, bytes;
|
|
|
|
for(line = 0; line < 64; line++)
|
|
{
|
|
// Setting the x-address register.
|
|
*selector = 4;
|
|
*data = line + 0xc0;
|
|
|
|
// Setting Y-Up mode.
|
|
*selector = 1;
|
|
*data = 1;
|
|
|
|
// Setting y-address.
|
|
*selector = 4;
|
|
*data = 0;
|
|
|
|
// Selecting data write register 7 and sending a line's bytes.
|
|
*selector = 7;
|
|
for(bytes = 0; bytes < 16; bytes++) *data = *vram++;
|
|
}
|
|
}
|