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/* LCD controller driver for 680 project.
*
* Copyright 2010, Duncan Smith
* GPL
*/
#include <graph.h>
#define VIDEO_ROWMODE 0x01
#define VIDEO_COLMODE 0x00
char video_row;
#define VIDEO_AUTOINC 0x02
#define VIDEO_AUTODEC 0x00
char video_increment;
#define VIDEO_ENABLED 0x00
#define VIDEO_DISABLED 0x20
char video_enabled;
#define VIDEO_6BIT 0x00
#define VIDEO_8BIT 0x40
char video_6bit;
char video_busy; // Always 0
char video_cur_row;
char video_cur_col;
void video_write(char);
char video_read(void);
void *video_compute_address(void);
int video_compute_shift(void);
void video_write(char data)
{
int shift = video_compute_shift();
short int data_mask = ~(0xff00 >> shift);
short int data_dat = data >> (shift-8);
void *addr = video_compute_address();
*((short int *)addr) &= data_mask;
*((short int *)addr) |= data_dat;
return;
}
char video_read(void)
{
int shift = video_compute_shift();
void *addr = video_compute_address();
short int data = *((short int *)addr);
data <<= (shift-8);
data &= 0xff;
return;
}
void *video_compute_address()
{
void *addr;
int off;
addr = LCD_MEM;
addr += (video_cur_row) * (240 / 8);
if (video_6bit == VIDEO_6BIT)
off = video_cur_col * 6 / 8;
else
off = video_cur_col;
return addr + off;
}
int video_compute_shift()
{
if (video_6bit == VIDEO_8BIT)
return 0;
return (video_cur_col * 6) % 8;
}
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