From a7757eed41f9f005eee2245f13e3a9605f3a45c9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Lindqvist?= <bjourne@gmail.com>
Date: Mon, 3 Aug 2015 23:48:08 +0200
Subject: [PATCH] VM: new method context::address_to_error

---
 vm/contexts.cpp | 17 +++++++++++++++++
 vm/contexts.hpp |  1 +
 vm/errors.cpp   | 18 ++++--------------
 3 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/vm/contexts.cpp b/vm/contexts.cpp
index 88d27fb484..3c657bcb62 100644
--- a/vm/contexts.cpp
+++ b/vm/contexts.cpp
@@ -42,6 +42,23 @@ void context::fill_stack_seg(cell top_ptr, segment* seg, cell pattern) {
 #endif
 }
 
+vm_error_type context::address_to_error(cell addr) {
+  if (datastack_seg->underflow_p(addr))
+    return ERROR_DATASTACK_UNDERFLOW;
+  if (datastack_seg->overflow_p(addr))
+    return ERROR_DATASTACK_OVERFLOW;
+  if (retainstack_seg->underflow_p(addr))
+    return ERROR_RETAINSTACK_UNDERFLOW;
+  if (retainstack_seg->overflow_p(addr))
+    return ERROR_RETAINSTACK_OVERFLOW;
+  /* These are flipped because the callstack grows downwards. */
+  if (callstack_seg->underflow_p(addr))
+    return ERROR_CALLSTACK_OVERFLOW;
+  if (callstack_seg->overflow_p(addr))
+    return ERROR_CALLSTACK_UNDERFLOW;
+  return ERROR_MEMORY;
+}
+
 void context::reset() {
   reset_datastack();
   reset_retainstack();
diff --git a/vm/contexts.hpp b/vm/contexts.hpp
index b9e04fe302..c13f3a0444 100644
--- a/vm/contexts.hpp
+++ b/vm/contexts.hpp
@@ -49,6 +49,7 @@ struct context {
   void reset();
   void fix_stacks();
   void fill_stack_seg(cell top_ptr, segment* seg, cell pattern);
+  vm_error_type address_to_error(cell addr);
 
   cell peek() { return *(cell*)datastack; }
 
diff --git a/vm/errors.cpp b/vm/errors.cpp
index 6586bd4e0b..62e30dbbb6 100644
--- a/vm/errors.cpp
+++ b/vm/errors.cpp
@@ -117,20 +117,10 @@ void factor_vm::verify_memory_protection_error(cell addr) {
 void factor_vm::memory_protection_error(cell pc, cell addr) {
   if (code->safepoint_p(addr))
     safepoint.handle_safepoint(this, pc);
-  else if (ctx->datastack_seg->underflow_p(addr))
-    general_error(ERROR_DATASTACK_UNDERFLOW, false_object, false_object);
-  else if (ctx->datastack_seg->overflow_p(addr))
-    general_error(ERROR_DATASTACK_OVERFLOW, false_object, false_object);
-  else if (ctx->retainstack_seg->underflow_p(addr))
-    general_error(ERROR_RETAINSTACK_UNDERFLOW, false_object, false_object);
-  else if (ctx->retainstack_seg->overflow_p(addr))
-    general_error(ERROR_RETAINSTACK_OVERFLOW, false_object, false_object);
-  else if (ctx->callstack_seg->underflow_p(addr))
-    general_error(ERROR_CALLSTACK_OVERFLOW, false_object, false_object);
-  else if (ctx->callstack_seg->overflow_p(addr))
-    general_error(ERROR_CALLSTACK_UNDERFLOW, false_object, false_object);
-  else
-    general_error(ERROR_MEMORY, from_unsigned_cell(addr), false_object);
+  else {
+    vm_error_type type = ctx->address_to_error(addr);
+    general_error(type, from_unsigned_cell(addr), false_object);
+  }
 }
 
 /* Allocates memory */