#include "devices/kbd.h"
+#include <ctype.h>
#include <debug.h>
#include <stdio.h>
+#include <string.h>
+#include "devices/intq.h"
#include "threads/interrupt.h"
#include "threads/io.h"
+/* Keyboard data register port. */
+#define DATA_REG 0x60
+
+/* Shift state bits. */
+#define LSHIFT 0x01 /* Left Shift. */
+#define RSHIFT 0x02 /* Right Shift. */
+#define LALT 0x04 /* Left Alt. */
+#define RALT 0x08 /* Right Alt. */
+#define LCTRL 0x10 /* Left Ctrl. */
+#define RCTRL 0x20 /* Right Ctrl. */
+#define CAPS 0x40 /* Caps Lock. */
+
+/* Current shift state. */
+static unsigned shift_state;
+
+/* Keyboard buffer. */
+static struct intq buffer;
+
+static intr_handler_func keyboard_interrupt;
+
+/* Initializes the keyboard. */
+void
+kbd_init (void)
+{
+ intq_init (&buffer, "keyboard");
+ intr_register (0x21, 0, INTR_OFF, keyboard_interrupt, "8042 Keyboard");
+}
+
+/* Retrieves a key from the keyboard buffer.
+ If the buffer is empty, waits for a key to be pressed. */
+uint8_t
+kbd_getc (void)
+{
+ uint8_t key;
+
+ intq_lock (&buffer);
+ key = intq_getc (&buffer);
+ intq_unlock (&buffer);
+
+ return key;
+}
+\f
+/* Maps a set of contiguous scancodes into characters. */
+struct keymap
+ {
+ uint8_t first_scancode; /* First scancode. */
+ const char *chars; /* chars[0] has scancode first_scancode,
+ chars[1] has scancode first_scancode + 1,
+ and so on to the end of the string. */
+ };
+
+/* Keys that produce the same characters regardless of whether
+ the Shift keys are down. Case of letters is an exception
+ that we handle elsewhere. */
+static const struct keymap invariant_keymap[] =
+ {
+ {0x01, "\033"},
+ {0x0e, "\b"},
+ {0x0f, "\tQWERTYUIOP"},
+ {0x1c, "\n"},
+ {0x1e, "ASDFGHJKL"},
+ {0x2c, "ZXCVBNM"},
+ {0x37, "*"},
+ {0x39, " "},
+ {0, NULL},
+ };
+
+/* Characters for keys pressed without Shift, for those keys
+ where it matters. */
+static const struct keymap unshifted_keymap[] =
+ {
+ {0x02, "1234567890-="},
+ {0x1a, "[]"},
+ {0x27, ";'`"},
+ {0x2b, "\\"},
+ {0x33, ",./"},
+ {0, NULL},
+ };
+
+/* Characters for keys pressed with Shift, for those keys where
+ it matters. */
+static const struct keymap shifted_keymap[] =
+ {
+ {0x02, "!@#$%^&*()_+"},
+ {0x1a, "{}"},
+ {0x27, ":\"~"},
+ {0x2b, "|"},
+ {0x33, "<>?"},
+ {0, NULL},
+ };
+
+static bool map_key (const struct keymap[], unsigned scancode, uint8_t *);
+
static void
-irq21_keyboard (struct intr_frame *args UNUSED)
+keyboard_interrupt (struct intr_frame *args UNUSED)
{
- printf ("Keyboard!\n");
- inb (0x60);
+ /* Status of shift keys. */
+ bool shift = (shift_state & (LSHIFT | RSHIFT)) != 0;
+ bool alt = (shift_state & (LALT | RALT)) != 0;
+ bool ctrl = (shift_state & (LCTRL | RCTRL)) != 0;
+ bool caps = (shift_state & CAPS) != 0;
+
+ /* Keyboard scancode. */
+ unsigned code;
+
+ /* False if key pressed, true if key released. */
+ bool release;
+
+ /* Character that corresponds to `code'. */
+ uint8_t c;
+
+ /* Read scancode, including second byte if prefix code. */
+ code = inb (DATA_REG);
+ if (code == 0xe0)
+ code = (code << 8) | inb (DATA_REG);
+
+ /* Bit 0x80 distinguishes key press from key release
+ (even if there's a prefix). */
+ release = (code & 0x80) != 0;
+ code &= ~0x80u;
+
+ /* Interpret key. */
+ if (code == 0x3a)
+ {
+ /* Caps Lock. */
+ if (!release)
+ shift_state ^= CAPS;
+ }
+ else if (map_key (invariant_keymap, code, &c)
+ || (!shift && map_key (unshifted_keymap, code, &c))
+ || (shift && map_key (shifted_keymap, code, &c)))
+ {
+ /* Ordinary character. */
+ if (!release)
+ {
+ /* Handle Ctrl, Shift.
+ Note that Ctrl overrides Shift. */
+ if (ctrl && c >= 0x40 && c < 0x60)
+ {
+ /* A is 0x41, Ctrl+A is 0x01, etc. */
+ c -= 0x40;
+ }
+ else if (shift == caps)
+ c = tolower (c);
+
+ /* Handle Alt by setting the high bit.
+ This 0x80 is unrelated to the one used to
+ distinguish key press from key release. */
+ if (alt)
+ c += 0x80;
+
+ /* Append to keyboard buffer. */
+ if (!intq_full (&buffer))
+ intq_putc (&buffer, c);
+ }
+ }
+ else
+ {
+ /* Table of shift keys.
+ Maps a keycode into a shift_state bit. */
+ static const unsigned shift_keys[][2] =
+ {
+ { 0x2a, LSHIFT},
+ { 0x36, RSHIFT},
+ { 0x38, LALT},
+ {0xe038, RALT},
+ { 0x1d, LCTRL},
+ {0xe01d, RCTRL},
+ {0, 0},
+ };
+
+ const unsigned (*key)[2];
+
+ /* Scan the table. */
+ for (key = shift_keys; (*key)[0] != 0; key++)
+ if ((*key)[0] == code)
+ {
+ if (release)
+ shift_state &= ~(*key)[1];
+ else
+ shift_state |= (*key)[1];
+ break;
+ }
+ }
}
-void
-kbd_init (void)
+/* Scans the array of keymaps K for SCANCODE.
+ If found, sets *C to the corresponding character and returns
+ true.
+ If not found, returns false and C is ignored. */
+static bool
+map_key (const struct keymap k[], unsigned scancode, uint8_t *c)
{
- intr_register (0x21, 0, INTR_OFF, irq21_keyboard, "8042 Keyboard");
+ for (; k->first_scancode != 0; k++)
+ if (scancode >= k->first_scancode
+ && scancode < k->first_scancode + strlen (k->chars))
+ {
+ *c = k->chars[scancode - k->first_scancode];
+ return true;
+ }
+
+ return false;
}
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