X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=bootcensus;a=blobdiff_plain;f=src%2Fkeyb.c;fp=src%2Fkeyb.c;h=c5a672c840bde879761f38ff589c980b43b36d4b;hp=0000000000000000000000000000000000000000;hb=a2f94f569a4c99204de02814a20098a71527e913;hpb=d1e8a437c1fab4535f82c4c214ec3330ac32e48d

diff --git a/src/keyb.c b/src/keyb.c
new file mode 100644
index 0000000..c5a672c
--- /dev/null
+++ b/src/keyb.c
@@ -0,0 +1,132 @@
+#include "keyb.h"
+#include "intr.h"
+#include "asmops.h"
+
+#define KB_IRQ	1
+#define KB_PORT		0x60
+
+/* table with rough translations from set 1 scancodes to ASCII-ish */
+static int scantbl[] = {
+	0, KB_ESC, '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '-', '=', '\b',		/* 0 - e */
+	'\t', 'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p', '[', ']', '\n',			/* f - 1c */
+	KB_LCTRL, 'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', '\'', '`',				/* 1d - 29 */
+	KB_LSHIFT, '\\', 'z', 'x', 'c', 'v', 'b', 'n', 'm', ',', '.', '/', KB_RSHIFT,			/* 2a - 36 */
+	KB_NUM_MUL, KB_LALT, ' ', KB_CAPSLK, KB_F1, KB_F2, KB_F3, KB_F4, KB_F5, KB_F6, KB_F7, KB_F8, KB_F9, KB_F10,			/* 37 - 44 */
+	KB_NUMLK, KB_SCRLK, KB_NUM_7, KB_NUM_8, KB_NUM_9, KB_NUM_MINUS, KB_NUM_4, KB_NUM_5, KB_NUM_6, KB_NUM_PLUS,	/* 45 - 4e */
+	KB_NUM_1, KB_NUM_2, KB_NUM_3, KB_NUM_0, KB_NUM_DOT, KB_SYSRQ, 0, 0, KB_F11, KB_F12,						/* 4d - 58 */
+	0, 0, 0, 0, 0, 0, 0,															/* 59 - 5f */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,									/* 60 - 6f */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0									/* 70 - 7f */
+};
+
+static void kbintr();
+
+#define BUFSZ	64
+#define ADVANCE(x)	((x) = ((x) + 1) & (BUFSZ - 1))
+
+static int buffer[BUFSZ];
+static int buf_ridx, buf_widx;
+
+static unsigned int num_pressed;
+static unsigned char keystate[256];
+
+void kb_init(void)
+{
+	interrupt(IRQ_TO_INTR(KB_IRQ), kbintr);
+}
+
+int kb_isdown(int key)
+{
+	switch(key) {
+	case KB_ANY:
+		return num_pressed;
+
+	case KB_ALT:
+		return keystate[KB_LALT] + keystate[KB_RALT];
+
+	case KB_CTRL:
+		return keystate[KB_LCTRL] + keystate[KB_RCTRL];
+	}
+	return keystate[key];
+}
+
+void kb_wait(void)
+{
+	int key;
+	while((key = kb_getkey()) == -1) {
+		/* put the processor to sleep while waiting for keypresses, but first
+		 * make sure interrupts are enabled, or we'll sleep forever
+		 */
+		enable_intr();
+		halt_cpu();
+	}
+	kb_putback(key);
+}
+
+int kb_getkey(void)
+{
+	int res;
+
+	if(buf_ridx == buf_widx) {
+		return -1;
+	}
+	res = buffer[buf_ridx];
+	ADVANCE(buf_ridx);
+	return res;
+}
+
+void kb_putback(int key)
+{
+	/* go back a place */
+	if(--buf_ridx < 0) {
+		buf_ridx += BUFSZ;
+	}
+
+	/* if the write end hasn't caught up with us, go back one place
+	 * and put it there, otherwise just overwrite the oldest key which
+	 * is right where we were.
+	 */
+	if(buf_ridx == buf_widx) {
+		ADVANCE(buf_ridx);
+	}
+
+	buffer[buf_ridx] = key;
+}
+
+static void kbintr()
+{
+	unsigned char code;
+	int key, press;
+
+	code = inb(KB_PORT);
+
+	if(code >= 128) {
+		press = 0;
+		code -= 128;
+
+		if(num_pressed > 0) {
+			num_pressed--;
+		}
+	} else {
+		press = 1;
+
+		num_pressed++;
+	}
+
+	key = scantbl[code];
+
+	if(press) {
+		/* append to buffer */
+		buffer[buf_widx] = key;
+		ADVANCE(buf_widx);
+		/* if the write end overtook the read end, advance the read end
+		 * too, to discard the oldest keypress from the buffer
+		 */
+		if(buf_widx == buf_ridx) {
+			ADVANCE(buf_ridx);
+		}
+	}
+
+	/* and update keystate table */
+	keystate[key] = press;
+}