8d1879fe97
- clear_fb() fully working - trying to add positional buffer writes for fancy output - POSITION macro only seems to work for (0,0) coords for now haven't tested other edge cases yet
45 lines
1.4 KiB
C
45 lines
1.4 KiB
C
// Driver implementation for Jank's text frame buffer
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// Buffer can display 80 columns by 25 Rows
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// Start of buffer is at (real)address 0x000B8000
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// Memory at this section is divided into 16-bit cells
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// | 15-8 | 7-4 | 0-3
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// | Asci | FG | BG
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#include "framebuffer.h"
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static char* Frame_Buffer = (char*)FRAME_BUFFER_ADDR;
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static char* Frame_Buffer_End = (char*)(FRAME_BUFFER_ADDR + AREA);
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// Writes character to a given cell in the framebuffer
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// @cell parameter is the logical (linear)index into the buffer
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// _not_ the actual offset from the buffer addr
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// also proper location is caller's responsibility
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void write_cell_fb(unsigned cell, char c, char fg, char bg) {
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Frame_Buffer[cell] = c;
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Frame_Buffer[cell+1] = (fg & 0x0f << 4) | (bg & 0x0f);
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}
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/* this probably doesn't belong here */
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void print_fb(char* str, unsigned row, unsigned col) {
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// now we can write things to our buffer
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for(unsigned i =POSITION(row,col);i<strlen(str);i++) {
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write_cell_fb(FRAME_CELL(i), str[i], Green, White);
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}
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}
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void clear_fb() {
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char* cell;
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unsigned idx = Frame_Buffer_End - Frame_Buffer;
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for(cell=Frame_Buffer;cell != Frame_Buffer_End; cell+=2) {
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idx = Frame_Buffer_End - cell;
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write_cell_fb(idx, ' ', 0x00, 0x00);
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}
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}
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/* generic test func for this module */
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void test_fb() {
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clear_fb();
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//print_fb("Helo from the frame buffer", 0, 0);
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print_fb("adsf", 2, 2);
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}
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