47 lines
1.5 KiB
C
47 lines
1.5 KiB
C
// Driver implementation for Jank's text frame buffer
|
|
|
|
// Buffer can display 80 columns by 25 Rows
|
|
// Start of buffer is at (real)address 0x000B8000
|
|
// Memory at this section is divided into 16-bit cells
|
|
// | 15-8 | 7-4 | 0-3
|
|
// | Asci | FG | BG
|
|
#include "framebuffer.h"
|
|
#include "io.h"
|
|
|
|
static char* Frame_Buffer = (char*)FRAME_BUFFER_ADDR;
|
|
//static char* Frame_Buffer_End = (char*)(FRAME_BUFFER_ADDR + AREA);
|
|
|
|
// Writes character to a given cell in the framebuffer
|
|
// @cell parameter is the logical (linear)index into the buffer
|
|
// _not_ the actual offset from the buffer addr
|
|
// also proper location is caller's responsibility
|
|
void write_cell_fb(unsigned cell, char c, char fg, char bg) {
|
|
Frame_Buffer[cell] = c;
|
|
Frame_Buffer[cell+1] = (fg & 0x0f << 4) | (bg & 0x0f);
|
|
}
|
|
|
|
|
|
void clear_fb() {
|
|
for(unsigned cell=0;cell<AREA; cell+=2) {
|
|
write_cell_fb(cell, ' ', 0x00, 0x00);
|
|
}
|
|
}
|
|
|
|
void fb_move_cursor(unsigned short position) {
|
|
out_buffer(FB_CMD, FB_HIGH_CMD);
|
|
out_buffer(FB_DATA, ((position >> 8) & 0x00ff) );
|
|
out_buffer(FB_CMD, FB_LOW_CMD);
|
|
out_buffer(FB_DATA, position & 0x00ff);
|
|
}
|
|
/* generic test func for this module */
|
|
void test_fb() {
|
|
clear_fb();
|
|
write_cell_fb(FRAME_CELL(0), 'a', Green, White);
|
|
write_cell_fb(FRAME_CELL(1), 'b', Green, White);
|
|
write_cell_fb(FRAME_CELL(2), 'c', Green, White);
|
|
write_cell_fb(FRAME_CELL(3), 'c', Green, White);
|
|
write_cell_fb(FRAME_CELL(4), 'c', Green, White);
|
|
write_cell_fb(FRAME_CELL(5), 'c', Green, White);
|
|
fb_move_cursor(5);
|
|
}
|