backported fixes from 256boss

[bootcensus] / src / video.c

diff --git a/src/video.c b/src/video.c
index 702273a..ba89bad 100644 (file)
--- a/src/video.c
+++ b/src/video.c
@@ -15,10 +15,29 @@ GNU General Public License for more details.
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
-#include "video.h"
+#include <stdio.h>
 #include <string.h>
+#include "video.h"
+#include "vbe.h"
 #include "int86.h"
 
+#define REALPTR(s, o)  (void*)(((uint32_t)(s) << 4) + (uint32_t)(o))
+#define VBEPTR(x)              REALPTR(((x) & 0xffff0000) >> 16, (x) & 0xffff)
+#define VBEPTR_SEG(x)  (((x) & 0xffff0000) >> 16)
+#define VBEPTR_OFF(x)  ((x) & 0xffff)
+
+
+#define SAME_BPP(a, b) \
+       ((a) == (b) || ((a) == 16 && (b) == 15) || ((a) == 15 && (b) == 16) || \
+        ((a) == 32 && (b) == 24) || ((a) == 24 && (b) == 32))
+
+
+unsigned int color_mask(int nbits, int pos);
+
+static struct vbe_info *vbe_info;
+static uint16_t *modes;
+static int mode_count;
+static struct vbe_mode_info *mode_info;
 
 void set_vga_mode(int mode)
 {
@@ -28,3 +47,165 @@ void set_vga_mode(int mode)
        regs.eax = mode;
        int86(0x10, &regs);
 }
+
+static int init_once(void)
+{
+       int i;
+       static int done_init;
+
+       if(done_init) {
+               return vbe_info && modes ? 0 : -1;
+       }
+       done_init = 1;
+
+       /* check for VBE2 support and output some info */
+       if(!(vbe_info = vbe_get_info())) {
+               printf("VESA BIOS Extensions not available\n");
+               return -1;
+       }
+
+       printf("VBE Version: %x.%x\n", vbe_info->version >> 8, vbe_info->version & 0xff);
+       if(vbe_info->version < 0x200) {
+               printf("VBE >=2.0 not available. VBE 1.x support not implemented yet.");
+               return -1;
+       }
+
+       printf("Graphics adapter: %s, %s (%s)\n", (char*)VBEPTR(vbe_info->oem_vendor_name_ptr),
+                       (char*)VBEPTR(vbe_info->oem_product_name_ptr), (char*)VBEPTR(vbe_info->oem_product_rev_ptr));
+       printf("Video memory: %dkb\n", vbe_info->total_mem << 6);
+
+       modes = VBEPTR(vbe_info->vid_mode_ptr);
+
+       mode_count = 0;
+       for(i=0; i<1024; i++) { /* impose an upper limit to avoid inf-loops */
+               if(modes[i] == 0xffff) {
+                       break;  /* reached the end */
+               }
+               mode_count++;
+       }
+       return 0;
+}
+
+void *set_video_mode(int mode)
+{
+       if(init_once() == -1) return 0;
+       if(mode < 0) return 0;
+
+       if(!(mode_info = vbe_get_mode_info(mode))) {
+               return 0;
+       }
+
+       if(vbe_set_mode(mode | VBE_MODE_LFB) == -1) {
+               printf("Failed to set video mode %dx%d %dbpp\n", mode_info->xres, mode_info->yres, mode_info->bpp);
+               return 0;
+       }
+
+       return (void*)mode_info->fb_addr;
+}
+
+int find_video_mode_idx(int xsz, int ysz, int bpp)
+{
+       int i, best = -1, best_bpp = 0;
+       struct vbe_mode_info *inf;
+
+       if(init_once() == -1) return -1;
+
+       for(i=0; i<mode_count; i++) {
+               inf = vbe_get_mode_info(modes[i] | VBE_MODE_LFB);
+               if(!inf || inf->xres != xsz || inf->yres != ysz) {
+                       continue;
+               }
+               if((bpp <= 0 && inf->bpp > best_bpp) || SAME_BPP(inf->bpp, bpp)) {
+                       best = i;
+                       best_bpp = inf->bpp;
+               }
+       }
+
+       if(best == -1) {
+               printf("Requested video mode (%dx%d %dbpp) is unavailable\n", xsz, ysz, bpp);
+               return -1;
+       }
+       return best;
+}
+
+int video_mode_count(void)
+{
+       if(init_once() == -1) return 0;
+       return mode_count;
+}
+
+int video_mode_info(int n, struct video_mode *vid)
+{
+       struct vbe_mode_info *inf;
+
+       if(init_once() == -1) return -1;
+
+       if(!(inf = vbe_get_mode_info(modes[n] | VBE_MODE_LFB))) {
+               return -1;
+       }
+       vid->mode = modes[n];
+       vid->width = inf->xres;
+       vid->height = inf->yres;
+       vid->bpp = inf->bpp;
+       vid->rbits = inf->rmask_size;
+       vid->gbits = inf->gmask_size;
+       vid->bbits = inf->bmask_size;
+       vid->rshift = inf->rpos;
+       vid->gshift = inf->gpos;
+       vid->bshift = inf->bpos;
+       vid->rmask = color_mask(inf->rmask_size, inf->rpos);
+       vid->gmask = color_mask(inf->gmask_size, inf->gpos);
+       vid->bmask = color_mask(inf->bmask_size, inf->bpos);
+       return 0;
+}
+
+int get_color_bits(int *rbits, int *gbits, int *bbits)
+{
+       if(!mode_info) {
+               return -1;
+       }
+       *rbits = mode_info->rmask_size;
+       *gbits = mode_info->gmask_size;
+       *bbits = mode_info->bmask_size;
+       return 0;
+}
+
+int get_color_mask(unsigned int *rmask, unsigned int *gmask, unsigned int *bmask)
+{
+       if(!mode_info) {
+               return -1;
+       }
+       *rmask = color_mask(mode_info->rmask_size, mode_info->rpos);
+       *gmask = color_mask(mode_info->gmask_size, mode_info->gpos);
+       *bmask = color_mask(mode_info->bmask_size, mode_info->bpos);
+       return 0;
+}
+
+int get_color_shift(int *rshift, int *gshift, int *bshift)
+{
+       if(!mode_info) {
+               return -1;
+       }
+       *rshift = mode_info->rpos;
+       *gshift = mode_info->gpos;
+       *bshift = mode_info->bpos;
+       return 0;
+}
+
+unsigned int color_mask(int nbits, int pos)
+{
+       static unsigned int maskbits[] = {0, 1, 3, 7, 0xf, 0x1f, 0x3f, 0x7f, 0xff};
+       return maskbits[nbits] << pos;
+}
+
+const char *get_video_vendor(void)
+{
+       if(init_once() == -1) return 0;
+       return (char*)VBEPTR(vbe_info->oem_vendor_name_ptr);
+}
+
+int get_video_mem_size(void)
+{
+       if(init_once() == -1) return 0;
+       return vbe_info->total_mem << 6;
+}