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CPM OPERATING SYSTEMS/CPM 68K/1.0X SOURCES/v101/test/alloc.c

@@ -0,0 +1,95 @@
+/*
+ * C library -- alloc/free
+ */
+
+#define	logical	char *
+
+struct fb {
+	logical	size;
+	char	*next;
+};
+
+int	_freelist[] {
+	0,
+	-1,
+};
+logical	_slop	4;
+
+char *
+malloc(asize)
+logical asize;
+{
+	register logical rsize;
+	register logical np;
+	register logical cp;
+
+	if ((rsize = asize) == 0)
+		return(-1);
+	rsize += 3;
+	rsize = _andptr(rsize,~01);
+	for (;;) 
+	{
+		for (cp=_freelist; (np= cp->next) != -1; cp=np) 
+		{
+			if (np->size >= rsize) 
+			{
+				if (_addptr(rsize,_slop) >= np->size) 
+				{
+					cp->next = np->next;
+					return(&np->next);
+				}
+				cp = cp->next = _addptr(np , rsize);
+				cp->size = np->size - rsize;
+				cp->next = np->next;
+				np->size = rsize;
+				return(&np->next);
+			}
+		}
+		asize = (rsize < 1024) ? 1024: rsize;
+		if ((cp = sbrk(asize)) == -1) 
+		{
+			return (-1);
+		}
+		cp->size = asize;
+		free(&cp->next);
+	}
+}
+
+free(aptr)
+char *aptr;
+{
+	register logical ptr;
+	register logical cp;
+	register logical np;
+
+	ptr = aptr-4;
+	cp = _freelist;
+	while ((np = cp->next) < ptr)
+		cp = np;
+	if (_addptr(ptr,ptr->size) == np) 
+	{
+		ptr->size = _addptr(ptr->size,np->size);
+		ptr->next = np->next;
+		np = ptr;
+	} 
+	else
+		ptr->next = np;
+
+	if (_addptr(cp,cp->size) == ptr) 
+	{
+		cp->size = _addptr(cp->size,ptr->size);
+		cp->next = ptr->next;
+	} 
+	else
+		cp->next = ptr;
+}
+
+/* Fudge routines */
+_addptr (a,b)
+{
+	return(a+b);
+}
+_andptr (a,b)
+{
+	return(a&b);
+}