53 - simplest possible allocator: just one word at a time

But with tests this time.

mu.arc

@@ -18,6 +18,14 @@
   (= function* (table)))
 (enq clear initialization-fns*)
 
+(mac init-fn (name . body)
+  `(enq (fn () (= (function* ',name) ',body))
+        initialization-fns*))
+
+(mac on-init body
+  `(enq (fn () (run ',body))
+        initialization-fns*))
+
 (def add-fns (fns)
   (each (name . body) fns
     (= function*.name body)))

new.arc

@@ -0,0 +1,17 @@
+;; simple slab allocator. Intended only to carve out isolated memory for
+;; different threads/routines as they request.
+
+(on-init
+  ((Root_allocator_pointer location) <- literal 1000)  ; 1-1000 reserved
+)
+
+(init-fn new
+  ((2 integer-address) <- copy (Root_allocator_pointer integer))
+  ((3 integer) <- literal 1)
+  ((Root_allocator_pointer integer) <- add (Root_allocator_pointer integer) (3 integer))
+  (reply (2 integer-address)))
+; tests to express:
+; every call increments the pointer
+; no other function can increment the pointer
+; no later clause can increment the pointer after this base clause
+; multiple threads/routines can't call the allocator at once

new.arc.t

@@ -0,0 +1,19 @@
+(load "mu.arc")
+(load "new.arc")
+
+(reset)
+(add-fns
+  '((main)))
+(run function*!main)
+(if (~iso memory* (obj Root_allocator_pointer 1000))
+  (prn "F - allocator initialized"))
+
+(reset)
+(add-fns
+  '((main
+      ((x integer-address) <- new)
+      ((x integer-address deref) <- literal 34))))
+(run function*!main)
+;? (prn memory*)
+(if (~iso memory*!Root_allocator_pointer 1001)
+  (prn "F - 'new' increments allocator pointer"))

new.mu

@@ -1,14 +0,0 @@
-; memory map: 1-1000 reserved for the (currently non-reentrant) allocator
-(main
-  ((1 integer) <- literal 1000)  ; location 1 contains the high-water mark for the memory allocator
-  ((4 integer-address) <- new)
-  ((5 integer) <- copy (4 integer-address deref))
-)
-
-(new
-  ((2 integer-address) <- copy (1 integer))
-  ((3 integer) <- literal 1)
-  ((1 integer) <- add (1 integer) (3 integer))
-  (reply (2 integer-address)))
-
-;; vim:ft=scheme