改善FIFO缓冲区

07_day/bootpack.c

@@ -29,13 +29,14 @@ void HariMain(void)
 
 	for (;;) {
 		io_cli();
-		if (keybuf.next == 0) {
+		if (keybuf.len == 0) {
 			io_stihlt();
 		} else {
-			i = keybuf.data[0];
-			keybuf.next--;
-			for (j = 0; j < keybuf.next; j++) {
-				keybuf.data[j] = keybuf.data[j + 1];
+			i = keybuf.data[keybuf.next_r];
+			keybuf.len--;
+			keybuf.next_r++;
+			if (keybuf.next_r == 32) {
+				keybuf.next_r = 0;
 			}
 			io_sti();
 			sprintf(s, "%02X", i);

07_day/bootpack.h

@@ -76,7 +76,7 @@ void set_gatedesc(struct GATE_DESCRIPTOR *gd, int offset, int selector, int ar);
 /* int.c */
 struct KEYBUF {
 	unsigned char data[32];
-	int next;
+	int next_r, next_w, len;
 };
 void init_pic(void);
 void inthandler21(int *esp);

07_day/int.c

@@ -35,9 +35,13 @@ void inthandler21(int *esp)
 	unsigned char data, s[4];
 	io_out8(PIC0_OCW2, 0x61);	/* 通知PIC IRQ-01 已经受理完毕 */
 	data = io_in8(PORT_KEYDAT);
-	if (keybuf.next < 32) {
-		keybuf.data[keybuf.next] = data;
-		keybuf.next++;
+	if (keybuf.len < 32) {
+		keybuf.data[keybuf.next_w] = data;
+		keybuf.len++;
+		keybuf.next_w++;
+		if (keybuf.next_w == 32) {
+			keybuf.next_w = 0;
+		}
 	}
 	return;
 }