Add original unix v6

sys/ken/malloc.c

@@ -0,0 +1,87 @@
+#
+/*
+ */
+
+/*
+ * Structure of the coremap and swapmap
+ * arrays. Consists of non-zero count
+ * and base address of that many
+ * contiguous units.
+ * (The coremap unit is 64 bytes,
+ * the swapmap unit is 512 bytes)
+ * The addresses are increasing and
+ * the list is terminated with the
+ * first zero count.
+ */
+struct map
+{
+	char *m_size;
+	char *m_addr;
+};
+
+/*
+ * Allocate size units from the given
+ * map. Return the base of the allocated
+ * space.
+ * Algorithm is first fit.
+ */
+malloc(mp, size)
+struct map *mp;
+{
+	register int a;
+	register struct map *bp;
+
+	for (bp = mp; bp->m_size; bp++) {
+		if (bp->m_size >= size) {
+			a = bp->m_addr;
+			bp->m_addr =+ size;
+			if ((bp->m_size =- size) == 0)
+				do {
+					bp++;
+					(bp-1)->m_addr = bp->m_addr;
+				} while ((bp-1)->m_size = bp->m_size);
+			return(a);
+		}
+	}
+	return(0);
+}
+
+/*
+ * Free the previously allocated space aa
+ * of size units into the specified map.
+ * Sort aa into map and combine on
+ * one or both ends if possible.
+ */
+mfree(mp, size, aa)
+struct map *mp;
+{
+	register struct map *bp;
+	register int t;
+	register int a;
+
+	a = aa;
+	for (bp = mp; bp->m_addr<=a && bp->m_size!=0; bp++);
+	if (bp>mp && (bp-1)->m_addr+(bp-1)->m_size == a) {
+		(bp-1)->m_size =+ size;
+		if (a+size == bp->m_addr) {
+			(bp-1)->m_size =+ bp->m_size;
+			while (bp->m_size) {
+				bp++;
+				(bp-1)->m_addr = bp->m_addr;
+				(bp-1)->m_size = bp->m_size;
+			}
+		}
+	} else {
+		if (a+size == bp->m_addr && bp->m_size) {
+			bp->m_addr =- size;
+			bp->m_size =+ size;
+		} else if (size) do {
+			t = bp->m_addr;
+			bp->m_addr = a;
+			a = t;
+			t = bp->m_size;
+			bp->m_size = size;
+			bp++;
+		} while (size = t);
+	}
+}