pull exit check out of State::execute

4 files changed, 26 insertions, 21 deletions

diff --git a/corewords.cpp b/corewords.cpp
index 6aec5ab..97f53dc 100644
--- a/corewords.cpp
+++ b/corewords.cpp
@@ -168,19 +168,23 @@ execute:
         break;
     case 25: // exit
         state.ip = state.popr();
+        if (state.ip == 0) {
+            std::longjmp(state.jmpbuf,
+                static_cast<int>(State::Error::exit));
+        }
         break;
     case 26: // semic
         state.dict.add(findi("exit"));
         state.compiling(false);
         break;
-    case 27: // _jmp
-        state.ip = state.beyondip() - sizeof(Cell);
-        break;
-    case 28: // _jmp0
-        if (state.pop())
+    case 27: // _jmp0
+        if (state.pop()) {
             state.beyondip();
-        else
-            state.ip = state.beyondip() - sizeof(Cell);
+            break;
+        }
+        [[fallthrough]];
+    case 28: // _jmp
+        state.ip = state.beyondip() - sizeof(Cell);
         break;
     case 29: // depth
         state.push(state.size());
diff --git a/corewords.hpp b/corewords.hpp
index fcb00e8..020694f 100644
--- a/corewords.hpp
+++ b/corewords.hpp
@@ -44,8 +44,8 @@ private:
         "_@\0_!\0>r\0r>\0=\0"
         "<\0&\0|\0^\0"
         "<<\0>>\0:\0'\0execute\0"
-        "exit\0;\1_jmp\0"
-        "_jmp0\0depth\0_rdepth\0key\0";
+        "exit\0;\1_jmp0\0_jmp\0"
+        "depth\0_rdepth\0key\0";
 };
 
 #endif // ALEEFORTH_COREWORDS_HPP
diff --git a/state.cpp b/state.cpp
index 56ad8cd..c27d95b 100644
--- a/state.cpp
+++ b/state.cpp
@@ -35,20 +35,20 @@ State::Error State::execute(Addr addr)
 {
     auto stat = setjmp(jmpbuf);
     if (!stat) {
-        ip = 0;
+        if (addr < CoreWords::WordCount) {
+            CoreWords::run(addr, *this);
+        } else {
+            auto ins = addr;
 
-        auto ins = addr;
-        for (;;) {
-            CoreWords::run(ins, *this);
-
-            if (!ip)
-                break;
-
-            ip += sizeof(Cell);
-            ins = dict.read(ip);
+            for (;;) {
+                CoreWords::run(ins, *this);
+                ip += sizeof(Cell);
+                ins = dict.read(ip);
+            }
         }
     } else {
-        return static_cast<State::Error>(stat);
+        auto err = static_cast<State::Error>(stat);
+        return err == State::Error::exit ? State::Error::none : err;
     }
 
     return State::Error::none;
diff --git a/state.hpp b/state.hpp
index 69db2f6..76b3c67 100644
--- a/state.hpp
+++ b/state.hpp
@@ -37,7 +37,8 @@ struct State
         pushr,
         popr,
         top,
-        pick
+        pick,
+        exit
     };
 
     Addr ip = 0;