initial hasty attempt at porting over my VBE code

[bootcensus] / src / video.c

diff --git a/src/video.c b/src/video.c
index 702273a..277dcbd 100644 (file)
--- a/src/video.c
+++ b/src/video.c
@@ -15,10 +15,26 @@ 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))
+
+
+
+static struct vbe_info *vbe_info;
+static struct vbe_mode_info *mode_info;
 
 void set_vga_mode(int mode)
 {
@@ -28,3 +44,93 @@ void set_vga_mode(int mode)
        regs.eax = mode;
        int86(0x10, &regs);
 }
+
+void *set_video_mode(int xsz, int ysz, int bpp)
+{
+       int i;
+       static uint16_t *modes;
+       uint16_t best = 0;
+
+       /* check for VBE2 support and output some info */
+       if(!vbe_info) {
+               if(!(vbe_info = vbe_get_info())) {
+                       printf("VESA BIOS Extensions not available\n");
+                       return 0;
+               }
+
+               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 0;
+               }
+
+               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);
+       }
+
+       for(i=0; i<1024; i++) { /* impose an upper limit to avoid inf-loops */
+               if(modes[i] == 0xffff) {
+                       break;  /* reached the end */
+               }
+
+               mode_info = vbe_get_mode_info(modes[i] | VBE_MODE_LFB);
+               if(!mode_info || mode_info->xres != xsz || mode_info->yres != ysz) {
+                       continue;
+               }
+               if(SAME_BPP(mode_info->bpp, bpp)) {
+                       best = modes[i];
+               }
+       }
+
+       if(best) {
+               mode_info = vbe_get_mode_info(best);
+       } else {
+               printf("Requested video mode (%dx%d %dbpp) is unavailable\n", xsz, ysz, bpp);
+               return 0;
+       }
+
+       if(vbe_set_mode(best | 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 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)
+{
+       static unsigned int maskbits[] = {0, 1, 3, 7, 0xf, 0x1f, 0x3f, 0x7f, 0xff};
+       if(!mode_info) {
+               return -1;
+       }
+       *rmask = maskbits[mode_info->rmask_size] << mode_info->rpos;
+       *gmask = maskbits[mode_info->gmask_size] << mode_info->gpos;
+       *bmask = maskbits[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;
+}
+