1 files changed, 51 insertions, 0 deletions
diff --git a/kbd.c b/kbd.c
new file mode 100644
index 0000000..a4dd381
--- /dev/null
+++ b/kbd.c
@@ -0,0 +1,51 @@
+#include "types.h"
+#include "x86.h"
+#include "defs.h"
+#include "kbd.h"
+
+int
+kbd_getc(void)
+{
+  static uint shift;
+  static uchar *charcode[4] = {
+    normalmap, shiftmap, ctlmap, ctlmap
+  };
+  uint st, data, c;
+
+  st = inb(KBSTATP);
+  if((st & KBS_DIB) == 0)
+    return -1;
+  data = inb(KBDATAP);
+
+  if(data == 0xE0) {
+    shift |= E0ESC;
+    return 0;
+  } else if(data & 0x80) {
+    // Key released
+    data = (shift & E0ESC ? data : data & 0x7F);
+    shift &= ~(shiftcode[data] | E0ESC);
+    return 0;
+  } else if(shift & E0ESC) {
+    // Last character was an E0 escape; or with 0x80
+    data |= 0x80;
+    shift &= ~E0ESC;
+  }
+
+  shift |= shiftcode[data];
+  shift ^= togglecode[data];
+  c = charcode[shift & (CTL | SHIFT)][data];
+  if(shift & CAPSLOCK) {
+    if('a' <= c && c <= 'z')
+      c += 'A' - 'a';
+    else if('A' <= c && c <= 'Z')
+      c += 'a' - 'A';
+  }
+  return c;
+}
+
+void
+kbd_intr(void)
+{
+  console_intr(kbd_getc);
+}
+