1 files changed, 128 insertions, 0 deletions
diff --git a/os/boot/mpc/qio.c b/os/boot/mpc/qio.c
new file mode 100644
index 00000000..e014433e
--- /dev/null
+++ b/os/boot/mpc/qio.c
@@ -0,0 +1,128 @@
+#include "u.h"
+#include "lib.h"
+#include "mem.h"
+#include "dat.h"
+#include "fns.h"
+#include "io.h"
+
+struct Queue {
+	Block*	first;
+	Block*	last;
+	void	(*kick)(void*);
+	void*	arg;
+	long	len;
+};
+
+Block *
+iallocb(int n)
+{
+	Block *b;
+
+	b = (Block*)malloc(sizeof(Block)+n);
+	b->data = (uchar*)b + sizeof(Block);
+	b->rp = b->wp = b->data;
+	b->lim = b->data + n;
+	b->next = 0;
+	b->magic = 0xcafebee0;
+	return b;
+}
+
+void
+freeb(Block *b)
+{
+	if(b){
+		if(b->magic != 0xcafebee0)
+			panic("freeb");
+		b->magic = 0;
+		b->next = (Block*)0xdeadbabe;
+		free(b);
+	}
+}
+
+Queue *
+qopen(int limit, int msg, void (*kick)(void*), void *arg)
+{
+	Queue *q;
+
+	USED(limit, msg);
+	q = (Queue*)malloc(sizeof(Queue));
+	q->first = q->last = 0;
+	q->kick = kick;
+	q->arg = arg;
+	q->len = 0;
+	return q;
+}
+
+Block *
+qget(Queue *q)
+{
+	int s;
+	Block *b;
+
+	s = splhi();
+	if((b = q->first) != 0){
+		q->first = b->next;
+		b->next = 0;
+		q->len -= BLEN(b);
+		if(q->len < 0)
+			panic("qget");
+	}
+	splx(s);
+	return b;
+}
+
+void
+qbwrite(Queue *q, Block *b)
+{
+	int s;
+
+	s = splhi();
+	b->next = 0;
+	if(q->first == 0)
+		q->first = b;
+	else
+		q->last->next = b;
+	q->last = b;
+	q->len += BLEN(b);
+	splx(s);
+	if(q->kick)
+		q->kick(q->arg);
+}
+
+long
+qlen(Queue *q)
+{
+	return q->len;
+}
+
+int
+qbgetc(Queue *q)
+{
+	Block *b;
+	int s, c;
+
+	c = -1;
+	s = splhi();
+	while(c < 0 && (b = q->first) != nil){
+		if(b->rp < b->wp){
+			c = *b->rp++;
+			q->len--;
+		}
+		if(b->rp >= b->wp){
+			q->first = b->next;
+			b->next = nil;
+		}
+	}
+	splx(s);
+	return c;
+}
+
+void
+qbputc(Queue *q, int c)
+{
+	Block *b;
+
+	b = iallocb(1);
+	*b->wp++ = c;
+	qbwrite(q, b);
+}