+#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;
+}