Add a first cut at text.

[netwatch.git] / video / text.c

diff --git a/video/text.c b/video/text.c
new file mode 100644 (file)
index 0000000..c9068b9
--- /dev/null
+++ b/video/text.c
@@ -0,0 +1,95 @@
+#include <io.h>
+#include <text.h>
+#include <paging.h>
+#include <minilib.h>
+#include <stdint.h>
+
+static unsigned char _font[256 * 32];
+
+/* Must be called from a firstrun context, where we don't care about saving
+ * 0x3CE state. */
+void text_init()
+{
+       unsigned char oldread;
+       outb(0x3CE, 0x05 /* Mode register */);
+       outb(0x3CF, inb(0x3CF) & ~(0x10 /* Odd/even */));
+       outb(0x3CE, 0x04 /* Read register */);
+       oldread = inb(0x3CF);
+       outb(0x3CF, 0x02 /* Font plane */);
+       memcpy(_font, p2v(0xB8000), sizeof(_font));
+       outb(0x3CF, oldread);
+}
+
+void text_render(unsigned char *buf, unsigned int x, unsigned int y, unsigned int w, unsigned int h)
+{
+       unsigned char *video = p2v(0xB8000);
+       unsigned int textx = x / 9;
+       unsigned int texty = y / 14;
+       unsigned int cx, cy;
+       unsigned char ch, at, font;
+       
+       for (cy = y; cy < (y + h); cy++)
+       {
+               texty = cy / 14;
+               textx = cx / 9;
+               ch = video[texty * 50 + textx * 2];
+               at = video[texty * 50 + textx * 2 + 1];
+               font = _font[ch * 32 + cy % 14];
+               for (cx = x; cx < (x + w); cx++)
+               {
+                       unsigned int pos = cx % 9;
+                       if (pos == 0)
+                       {
+                               textx = cx / 9;
+                               ch = video[texty * 50 + textx * 2];
+                               at = video[texty * 50 + textx * 2 + 1];
+                               font = _font[ch * 32 + cy % 14];
+                       }
+                       /* XXX always BGR888 */
+                       if (pos == 8)   /* 9th pixel is cloned */
+                               pos = 7;
+                       if ((font >> (7 - pos)) & 1)
+                       {
+                               *(buf++) = (at & 0x01) ? 0xFF : 0x00;
+                               *(buf++) = (at & 0x02) ? 0xFF : 0x00;
+                               *(buf++) = (at & 0x04) ? 0xFF : 0x00;
+                       } else {
+                               *(buf++) = (at & 0x10) ? 0xFF : 0x00;
+                               *(buf++) = (at & 0x20) ? 0xFF : 0x00;
+                               *(buf++) = (at & 0x40) ? 0xFF : 0x00;
+                       }
+               }
+       }
+}
+
+uint32_t text_checksum(int x, int y, int w, int h)
+{
+       unsigned char *video = p2v(0xB8000);
+       unsigned int textx = x / 9;
+       unsigned int texty = y / 14;
+       int cx, cy;
+       unsigned char ch, at;
+       uint32_t cksm = 0;
+       
+       for (cy = y; cy < (y + h); cy++)
+       {
+               texty = cy / 14;
+               textx = cx / 9;
+               ch = video[texty * 50 + textx * 2];
+               at = video[texty * 50 + textx * 2 + 1];
+               for (cx = x; cx < (x + w); cx++)
+               {
+                       unsigned int pos = cx % 9;
+                       if (pos == 0)
+                       {
+                               textx = cx / 9;
+                               ch = video[texty * 50 + textx * 2];
+                               at = video[texty * 50 + textx * 2 + 1];
+                       }
+                       
+                       cksm += ch + (at << 16);
+               }
+       }
+       
+       return cksm;
+}