1 files changed, 54 insertions, 3 deletions
diff --git a/kernel/memory/frame.dats b/kernel/memory/frame.dats
index 26ff412..8578e8f 100644
--- a/kernel/memory/frame.dats
+++ b/kernel/memory/frame.dats
@@ -2,6 +2,13 @@
 
 #define ATS_DYNLOADFLAG 0
 
+macdef invalid_area = @{
+  base_addr = the_null_ptr,
+  length = 1,
+  type = 0u,
+  reserved = 0
+}
+
 staload "./frame.sats"
 staload "kernel/bootinfo/multiboot.sats"
 
@@ -12,19 +19,63 @@ implement containing_address(address) : frame_t =
     counter = $UN.cast{size_t}(address) / i2sz(PAGE_SIZE)
   }
 
-fn choose_next_area{l,k : agz}(pf : !frame_allocator_t@l, bf : !boot_info_t @ k | p : ptr l, b : ptr k) : void = let 
+fn containing_area(area : memory_area_t) : frame_t = containing_address(ptr_add<uint8>(area.base_addr,area.length - i2sz(1)))
 
+//FIX: function doesn't handle no frames left
+fn choose_next_area{l,k : agz}(pf : !frame_allocator_t@l, bf : !boot_info_t @ k | p : ptr l, b : ptr k) : void = let 
+  val length = get_memory_mappings_n(bf | b)
+  val next_free_frame = p->next_free_frame
+  fun loop {n,i : nat | i < n} {l : agz} .<n-i>. (bf : !boot_info_t @ l | b : ptr l, i : size_t i, n : size_t n) : memory_area_t = let 
+    val entry = get_memory_mapping(bf | b ,i)
+    val fr = containing_area(entry)
+  in
+    if (entry.type = 1 && fr.num >= next_free_frame.num) then
+      entry
+    else if (i < n-1) then
+      loop (bf | b,succ(i),n)
+    else
+      entry //TODO: fix
+  end
 in 
+  if (length > 0) then //TODO: fix
+    p->current_area := loop(bf | b, i2sz(0), length);
 
+  if (p->current_area.length > 1) then
+    let
+      val start_frame = containing_address(p->current_area.base_addr)
+    in
+      if (p->next_free_frame.num < start_frame.num) then
+        p->next_free_frame := start_frame
+    end
 end 
 
+local
+
+var frame_allocator : frame_allocator_t
+
+in
+
+  implement frame_allocator_init() : allocptr = let
+    extern praxi __assert{l:addr} (ptr: ptr (l)): vtakeout0 (frame_allocator_t@l) // takeout proof  UNSAFE:
+    prval (pf, fpf) = __assert (addr@frame_allocator) 
+    val allocator = @{ 
+      next_free_frame = containing_address(the_null_ptr),
+      current_area = invalid_area
+    }
+  in
+
+    (pf, fpf | addr@frame_allocator)
+  end
+
+end
+
 implement allocate_frame(pf , bf | p,b) : frame_t = 
-  if (p->current_area.length > 1) then  let
+  if (p->current_area.type != 0u) then  let
       val area = p->current_area
       val frame = @{ num = p->next_free_frame.num }
 
       // last frame of current area
-      val last_frame_area = containing_address(ptr_add<uint8>(area.base_addr,area.length - i2sz(1)))
+      val last_frame_area = containing_area(area)
     in
       if (frame.num > last_frame_area.num) then (
         // all frames of current area are used, switch to next area