VirtualMachine: Add support for non-atomic scripts

Author: adazem009

src/engine/virtualmachine.cpp

@@ -2,6 +2,7 @@
 
 #include "virtualmachine.h"
 #include "../scratch/list.h"
+#include "../engine/engine.h"
 #include <iostream>
 
 #define MAX_REG_COUNT 1024
@@ -93,10 +94,10 @@ void VirtualMachine::setBytecode(const std::vector<unsigned int> &code)
 /*! Runs the script. */
 unsigned int *VirtualMachine::run()
 {
-    m_atEnd = false;
     return run(m_bytecode);
 }
 
+/*! Continues running the script from the given position (the first instruction is skipped). */
 unsigned int *VirtualMachine::run(unsigned int *pos)
 {
     static const void *dispatch_table[] = {
@@ -157,11 +158,14 @@ unsigned int *VirtualMachine::run(unsigned int *pos)
         &&do_init_procedure,
         &&do_call_procedure,
         &&do_add_arg,
-        &&do_read_arg
+        &&do_read_arg,
+        &&do_break_atomic
     };
     unsigned int *loopStart;
     unsigned int *loopEnd;
     size_t loopCount;
+    m_atEnd = false;
+    m_atomic = true;
     DISPATCH();
 
 do_halt:
@@ -257,8 +261,16 @@ do_loop_end : {
             pos = l.start;
         else
             m_loops.pop_back();
+        if (!m_atomic) {
+            m_engine->breakFrame();
+            return pos;
+        }
         DISPATCH();
     } else {
+        if (!m_atomic) {
+            m_engine->breakFrame();
+            return pos - 1;
+        }
         loopStart = run(l.start);
         if (!READ_LAST_REG()->toBool())
             pos = loopStart;
@@ -626,4 +638,8 @@ do_list_get_item : {
 do_read_arg:
     ADD_RET_VALUE(m_procedureArgs->operator[](*++pos));
     DISPATCH();
+
+do_break_atomic:
+    m_atomic = false;
+    DISPATCH();
 }

src/engine/virtualmachine.h

@@ -72,7 +72,8 @@ enum Opcode
     OP_INIT_PROCEDURE, /*!< Initializes the list of procedure (custom block) arguments. */
     OP_CALL_PROCEDURE, /*! Calls the procedure (custom block) with the index in the argument. */
     OP_ADD_ARG,        /*!< Adds a procedure (custom block) argument with the value from the last register. */
-    OP_READ_ARG        /*!< Reads the procedure (custom block) argument with the index in the argument and stores the value in the last register. */
+    OP_READ_ARG,       /*!< Reads the procedure (custom block) argument with the index in the argument and stores the value in the last register. */
+    OP_BREAK_ATOMIC    /*!< Breaks current frame at the end of the loop. */
 };
 
 }
@@ -108,15 +109,14 @@ class LIBSCRATCHCPP_EXPORT VirtualMachine
         void replaceReturnValue(const Value &v, unsigned int offset) { *m_regs[m_regCount - offset] = v; };
 
         unsigned int *run();
+        unsigned int *run(unsigned int *pos);
 
         /*! Returns true if the VM has reached the vm::OP_HALT instruction. */
         bool atEnd() const { return m_atEnd; };
 
     private:
-        unsigned int *run(unsigned int *pos);
-
         static inline const unsigned int instruction_arg_count[] = {
-            0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0
+            0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0
         };
 
         typedef struct
@@ -137,6 +137,7 @@ class LIBSCRATCHCPP_EXPORT VirtualMachine
         std::vector<std::vector<Value>> m_procedureArgTree;
         std::vector<Value> *m_procedureArgs = nullptr;
         std::vector<Value> *m_nextProcedureArgs = nullptr;
+        bool m_atomic;
 
         unsigned int **m_procedures = nullptr;
         std::vector<unsigned int *> m_proceduresVector;