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gol: Use memory-mapped IO
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apio 2023-08-03 09:26:35 +02:00
parent b5d146b492
commit bfcca3a220
Signed by: apio
GPG Key ID: B8A7D06E42258954
1 changed files with 24 additions and 11 deletions
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35
apps/gol.cpp
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@ -6,6 +6,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <time.h>
#include <unistd.h>
@ -24,6 +25,7 @@ static int g_fb_height;
static int g_fd;
static Cell* g_cells;
static char* g_fb;
static Result<void> fill_cells()
{
@ -47,27 +49,29 @@ static Cell& find_cell(int row, int column)
static constexpr int BYTES_PER_PIXEL = 4;
static char* g_buf;
static void draw_cells()
{
lseek(g_fd, 0, SEEK_SET);
const int CELL_WIDTH = g_fb_width / g_num_columns;
const int CELL_HEIGHT = g_fb_height / g_num_rows;
for (int i = 0; i < g_num_rows; i++)
{
memset(g_buf, 0, g_fb_width * BYTES_PER_PIXEL);
for (int j = 0; j < g_num_columns; j++)
{
auto& cell = find_cell(i, j);
if (cell.state) memset(g_buf + (j * CELL_WIDTH * BYTES_PER_PIXEL), 0xff, CELL_WIDTH * BYTES_PER_PIXEL);
}
char* buf = g_fb + (i * g_fb_width * CELL_HEIGHT * BYTES_PER_PIXEL);
for (int j = 0; j < CELL_HEIGHT; j++) { write(g_fd, g_buf, g_fb_width * BYTES_PER_PIXEL); }
auto& cell = find_cell(i, j);
u8 color = cell.state ? 0xff : 0x00;
for (int k = 0; k < CELL_HEIGHT; k++)
{
memset(buf + (j * CELL_WIDTH * BYTES_PER_PIXEL), color, CELL_WIDTH * BYTES_PER_PIXEL);
buf += g_fb_width * BYTES_PER_PIXEL;
}
}
}
msync(g_fb, g_fb_height * g_fb_width * BYTES_PER_PIXEL, MS_SYNC);
}
static int find_neighbors(int row, int column)
@ -137,7 +141,7 @@ Result<int> luna_main(int argc, char** argv)
else
srand((unsigned)time(NULL));
g_fd = open("/dev/fb0", O_WRONLY);
g_fd = open("/dev/fb0", O_RDWR);
if (g_fd < 0)
{
perror("gol: cannot open framebuffer for writing");
@ -149,7 +153,13 @@ Result<int> luna_main(int argc, char** argv)
TRY(fill_cells());
g_buf = (char*)TRY(calloc_impl(g_fb_width, BYTES_PER_PIXEL));
g_fb =
(char*)mmap(nullptr, g_fb_height * g_fb_width * BYTES_PER_PIXEL, PROT_READ | PROT_WRITE, MAP_SHARED, g_fd, 0);
if (g_fb == MAP_FAILED)
{
perror("gol: cannot map framebuffer into memory");
return 1;
}
draw_cells();
@ -162,5 +172,8 @@ Result<int> luna_main(int argc, char** argv)
usleep(delay_at_end * 1000);
munmap(g_fb, g_fb_height * g_fb_width * BYTES_PER_PIXEL);
free(g_cells);
return 0;
}