- compiler works for basic maths expressions and functions

- basic pointers and reading values from pointers works
- writing to pointers not yet implemented (looks painful so a problem
  for tomorrow)
- updated print library. the compiler has this hardcoded in all programs
  for now

resources/dsa/lib/memory/alloc.dsa

@@ -0,0 +1,37 @@
+dw global_arena_start: 0x30000
+dw global_arena_current: 0x30000
+dw global_arena_end: 0x40000
+
+arena_alloc:
+    // Just like bump allocator
+    push bpr
+    mov spr, bpr
+
+    ldw bpr, rg0, 8           // size argument
+    ldw global_arena_current, rg1
+
+    add rg1, rg0, rg2         // new_current = current + size
+    ldw global_arena_end, rg3
+
+    cmp rg2, rg3
+    jgt out_of_memory
+
+    stw rg2, global_arena_current
+    mov rg1, acc              // return old current
+    stw acc, bpr, 8
+
+    mov bpr, spr
+    pop bpr
+    return
+
+arena_reset:
+    // Reset to start
+    push bpr
+    mov spr, bpr
+
+    ldw global_arena_start, rg0
+    stw rg0, global_arena_current
+
+    mov bpr, spr
+    pop bpr
+    return