1 files changed, 52 insertions, 16 deletions

diff --git a/source/state.cpp b/source/state.cpp
index a2f424c..5daa772 100644
--- a/source/state.cpp
+++ b/source/state.cpp
@@ -18,27 +18,63 @@
 #include "core.hpp"
 #include "state.hpp"
 
-//#include <csetjmp>
+#include <csetjmp>
 #include <cstring>
 
-//static std::jmp_buf jmpbuf;
-Cell *SP = DICT.data() + DICT.size() - DS;
-Cell *RP = DICT.data() + DICT.size() - DS - RS;
 FuncList IP = nullptr;
-
 std::array<Cell, DictSize> DICT;
 
 Cell& HERE   = DICT[DIdxHere];
 Cell& LATEST = DICT[DIdxLatest];
 Cell& STATE  = DICT[DIdxState];
 
-void executor(FuncList *list)
+static std::jmp_buf jmpbuf;
+static Cell *SP = DICT.data() + DICT.size() - DS;
+static Cell *RP = DICT.data() + DICT.size() - DS - RS;
+
+void push(Cell value) {
+    if (SP >= DICT.data() + DICT.size())
+        std::longjmp(jmpbuf, static_cast<int>(Error::push));
+
+    *++SP = value;
+}
+
+Cell pop() {
+    if (SP - 1 < DICT.data() + DICT.size() - DS)
+        std::longjmp(jmpbuf, static_cast<int>(Error::pop));
+
+    return *SP--;
+}
+
+Cell *sp() {
+    return SP;
+}
+
+void rpush(Cell value) {
+    if (RP >= DICT.data() + DICT.size() - DS)
+        std::longjmp(jmpbuf, static_cast<int>(Error::rpush));
+
+    *++RP = value;
+}
+
+Cell rpop() {
+    if (RP - 1 < DICT.data() + DICT.size() - DS - RS)
+        std::longjmp(jmpbuf, static_cast<int>(Error::rpop));
+
+    return *RP--;
+}
+
+Cell *rp() {
+    return RP;
+}
+
+Error executor(FuncList *list)
 {
-    // TODO Use setjmp to recover from errors?
-    /*if (setjmp(jmpbuf) == 0)*/ {
+    auto result = static_cast<Error>(setjmp(jmpbuf));
+    FuncList body;
 
-        FuncList body;
-        void (*entry)(FuncList);
+    if (static_cast<int>(result) == 0) {
+        result = Error::none;
 
         // We are given the pointer to a list of function pointers.
         // Dereference once to retrieve the function pointer list.
@@ -65,19 +101,19 @@ entry:
             // their "calls".
             // If the word is pre-defined then the argument will simply be
             // ignored.
-            entry = (void (*)(FuncList))*body;
-            entry(body);
+            auto func = (void (*)(FuncList))*body;
+            func(body);
         }
-
-        //std::longjmp(jmpbuf, 1);
     }
+
+    return result;
 }
 
-void execute1(Word *word)
+Error execute1(Word *word)
 {
     // IP must initially be zero if executing a word at the top level.
     IP = 0;
-    executor(&word->list);
+    return executor(&word->list);
 }
 
 Word *find(const char *s, int len)