sim_bytepointers: initial WIP

erlang/apps/sim/src/sim_bytepointers.erl

@@ -0,0 +1,54 @@
+%%% -*- erlang-indent-level: 2 -*-
+%%%
+%%% simulator for pdp10-elf
+%%% Copyright (C) 2020-2021  Mikael Pettersson
+%%%
+%%% This file is part of pdp10-tools.
+%%%
+%%% pdp10-tools is free software: you can redistribute it and/or modify
+%%% it under the terms of the GNU General Public License as published by
+%%% the Free Software Foundation, either version 3 of the License, or
+%%% (at your option) any later version.
+%%%
+%%% pdp10-tools is distributed in the hope that it will be useful,
+%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
+%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%%% GNU General Public License for more details.
+%%%
+%%% You should have received a copy of the GNU General Public License
+%%% along with pdp10-tools.  If not, see <http://www.gnu.org/licenses/>.
+%%%
+%%%=============================================================================
+%%%
+%%% 2.11 Byte Manipulation
+
+-module(sim_bytepointers).
+
+-export([ handle_IBP/4
+        ]).
+
+-include("sim_core.hrl").
+
+%% 2.11 Byte Manipulation ======================================================
+
+%% IBP   - Increment Byte Pointer (A is zero)
+%% ADJBP - Adjust Byte Pointer (A is non-zero)
+
+-spec handle_IBP(#core{}, sim_mem:mem(), IR :: word(), #ea{})
+      -> {#core{}, sim_mem:mem(), {ok, integer()} | {error, {module(), term()}}}.
+handle_IBP(Core, Mem, IR, EA) ->
+  case sim_core:c(Core, Mem, EA) of
+    {ok, BP} ->
+      case IR band 8#17 of
+        0 -> ibp(Core, Mem, EA, BP);
+        AC -> adjbp(Core, Mem, AC, EA, BP)
+      end;
+    {error, Reason} ->
+      sim_core:page_fault(Core, Mem, EA, read, Reason,
+                          fun(Core1, Mem1) -> ?FUNCTION_NAME(Core1, Mem1, IR, EA) end)
+  end.
+
+%% Miscellaneous ===============================================================
+
+ibp(Core, Mem, EA, BP) ->
+  XXX.