unsigned long long int x;  __asm__("rdtsc\n\t"          "mov %%edx, %%ecx\n\t"          :"=A" (x));  return x;}#endif/*** The CHECK_FOR_INTERRUPT macro defined here looks to see if the** sqlite_interrupt() routine has been called.  If it has been, then** processing of the VDBE program is interrupted.**** This macro added to every instruction that does a jump in order to** implement a loop.  This test used to be on every single instruction,** but that meant we more testing that we needed.  By only testing the** flag on jump instructions, we get a (small) speed improvement.*/#define CHECK_FOR_INTERRUPT \   if( db->flags & SQLITE_Interrupt ) goto abort_due_to_interrupt;/*** Execute as much of a VDBE program as we can then return.**** sqliteVdbeMakeReady() must be called before this routine in order to** close the program with a final OP_Halt and to set up the callbacks** and the error message pointer.**** Whenever a row or result data is available, this routine will either** invoke the result callback (if there is one) or return with** SQLITE_ROW.**** If an attempt is made to open a locked database, then this routine** will either invoke the busy callback (if there is one) or it will** return SQLITE_BUSY.**** If an error occurs, an error message is written to memory obtained** from sqliteMalloc() and p->zErrMsg is made to point to that memory.** The error code is stored in p->rc and this routine returns SQLITE_ERROR.**** If the callback ever returns non-zero, then the program exits** immediately.  There will be no error message but the p->rc field is** set to SQLITE_ABORT and this routine will return SQLITE_ERROR.**** A memory allocation error causes p->rc to be set to SQLITE_NOMEM and this** routine to return SQLITE_ERROR.**** Other fatal errors return SQLITE_ERROR.**** After this routine has finished, sqliteVdbeFinalize() should be** used to clean up the mess that was left behind.*/int sqliteVdbeExec(  Vdbe *p                    /* The VDBE */){  int pc;                    /* The program counter */  Op *pOp;                   /* Current operation */  int rc = SQLITE_OK;        /* Value to return */  sqlite *db = p->db;        /* The database */  Mem *pTos;                 /* Top entry in the operand stack */  char zBuf[100];            /* Space to sprintf() an integer */#ifdef VDBE_PROFILE  unsigned long long start;  /* CPU clock count at start of opcode */  int origPc;                /* Program counter at start of opcode */#endif#ifndef SQLITE_OMIT_PROGRESS_CALLBACK  int nProgressOps = 0;      /* Opcodes executed since progress callback. */#endif  if( p->magic!=VDBE_MAGIC_RUN ) return SQLITE_MISUSE;  assert( db->magic==SQLITE_MAGIC_BUSY );  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );  p->rc = SQLITE_OK;  assert( p->explain==0 );  if( sqlite_malloc_failed ) goto no_mem;  pTos = p->pTos;  if( p->popStack ){    popStack(&pTos, p->popStack);    p->popStack = 0;  }  CHECK_FOR_INTERRUPT;  for(pc=p->pc; rc==SQLITE_OK; pc++){    assert( pc>=0 && pc<p->nOp );    assert( pTos<=&p->aStack[pc] );#ifdef VDBE_PROFILE    origPc = pc;    start = hwtime();#endif    pOp = &p->aOp[pc];    /* Only allow tracing if NDEBUG is not defined.    */#ifndef NDEBUG    if( p->trace ){      sqliteVdbePrintOp(p->trace, pc, pOp);    }#endif    /* Check to see if we need to simulate an interrupt.  This only happens    ** if we have a special test build.    */#ifdef SQLITE_TEST    if( sqlite_interrupt_count>0 ){      sqlite_interrupt_count--;      if( sqlite_interrupt_count==0 ){        sqlite_interrupt(db);      }    }#endif#ifndef SQLITE_OMIT_PROGRESS_CALLBACK    /* Call the progress callback if it is configured and the required number    ** of VDBE ops have been executed (either since this invocation of    ** sqliteVdbeExec() or since last time the progress callback was called).    ** If the progress callback returns non-zero, exit the virtual machine with    ** a return code SQLITE_ABORT.    */    if( db->xProgress ){      if( db->nProgressOps==nProgressOps ){        if( db->xProgress(db->pProgressArg)!=0 ){          rc = SQLITE_ABORT;          continue; /* skip to the next iteration of the for loop */        }        nProgressOps = 0;      }      nProgressOps++;    }#endif    switch( pOp->opcode ){/******************************************************************************* What follows is a massive switch statement where each case implements a** separate instruction in the virtual machine.  If we follow the usual** indentation conventions, each case should be indented by 6 spaces.  But** that is a lot of wasted space on the left margin.  So the code within** the switch statement will break with convention and be flush-left. Another** big comment (similar to this one) will mark the point in the code where** we transition back to normal indentation.**** The formatting of each case is important.  The makefile for SQLite** generates two C files "opcodes.h" and "opcodes.c" by scanning this** file looking for lines that begin with "case OP_".  The opcodes.h files** will be filled with #defines that give unique integer values to each** opcode and the opcodes.c file is filled with an array of strings where** each string is the symbolic name for the corresponding opcode.**** Documentation about VDBE opcodes is generated by scanning this file** for lines of that contain "Opcode:".  That line and all subsequent** comment lines are used in the generation of the opcode.html documentation** file.**** SUMMARY:****     Formatting is important to scripts that scan this file.**     Do not deviate from the formatting style currently in use.*******************************************************************************//* Opcode:  Goto * P2 ***** An unconditional jump to address P2.** The next instruction executed will be ** the one at index P2 from the beginning of** the program.*/case OP_Goto: {  CHECK_FOR_INTERRUPT;  pc = pOp->p2 - 1;  break;}/* Opcode:  Gosub * P2 ***** Push the current address plus 1 onto the return address stack** and then jump to address P2.**** The return address stack is of limited depth.  If too many** OP_Gosub operations occur without intervening OP_Returns, then** the return address stack will fill up and processing will abort** with a fatal error.*/case OP_Gosub: {  if( p->returnDepth>=sizeof(p->returnStack)/sizeof(p->returnStack[0]) ){    sqliteSetString(&p->zErrMsg, "return address stack overflow", (char*)0);    p->rc = SQLITE_INTERNAL;    return SQLITE_ERROR;  }  p->returnStack[p->returnDepth++] = pc+1;  pc = pOp->p2 - 1;  break;}/* Opcode:  Return * * ***** Jump immediately to the next instruction after the last unreturned** OP_Gosub.  If an OP_Return has occurred for all OP_Gosubs, then** processing aborts with a fatal error.*/case OP_Return: {  if( p->returnDepth<=0 ){    sqliteSetString(&p->zErrMsg, "return address stack underflow", (char*)0);    p->rc = SQLITE_INTERNAL;    return SQLITE_ERROR;  }  p->returnDepth--;  pc = p->returnStack[p->returnDepth] - 1;  break;}/* Opcode:  Halt P1 P2 ***** Exit immediately.  All open cursors, Lists, Sorts, etc are closed** automatically.**** P1 is the result code returned by sqlite_exec().  For a normal** halt, this should be SQLITE_OK (0).  For errors, it can be some** other value.  If P1!=0 then P2 will determine whether or not to** rollback the current transaction.  Do not rollback if P2==OE_Fail.** Do the rollback if P2==OE_Rollback.  If P2==OE_Abort, then back** out all changes that have occurred during this execution of the** VDBE, but do not rollback the transaction. **** There is an implied "Halt 0 0 0" instruction inserted at the very end of** every program.  So a jump past the last instruction of the program** is the same as executing Halt.*/case OP_Halt: {  p->magic = VDBE_MAGIC_HALT;  p->pTos = pTos;  if( pOp->p1!=SQLITE_OK ){    p->rc = pOp->p1;    p->errorAction = pOp->p2;    if( pOp->p3 ){      sqliteSetString(&p->zErrMsg, pOp->p3, (char*)0);    }    return SQLITE_ERROR;  }else{    p->rc = SQLITE_OK;    return SQLITE_DONE;  }}/* Opcode: Integer P1 * P3**** The integer value P1 is pushed onto the stack.  If P3 is not zero** then it is assumed to be a string representation of the same integer.*/case OP_Integer: {  pTos++;  pTos->i = pOp->p1;  pTos->flags = MEM_Int;  if( pOp->p3 ){    pTos->z = pOp->p3;    pTos->flags |= MEM_Str | MEM_Static;    pTos->n = strlen(pOp->p3)+1;  }  break;}/* Opcode: String * * P3**** The string value P3 is pushed onto the stack.  If P3==0 then a** NULL is pushed onto the stack.*/case OP_String: {  char *z = pOp->p3;  pTos++;  if( z==0 ){    pTos->flags = MEM_Null;  }else{    pTos->z = z;    pTos->n = strlen(z) + 1;    pTos->flags = MEM_Str | MEM_Static;  }  break;}/* Opcode: Variable P1 * ***** Push the value of variable P1 onto the stack.  A variable is** an unknown in the original SQL string as handed to sqlite_compile().** Any occurance of the '?' character in the original SQL is considered** a variable.  Variables in the SQL string are number from left to** right beginning with 1.  The values of variables are set using the** sqlite_bind() API.*/case OP_Variable: {  int j = pOp->p1 - 1;  pTos++;  if( j>=0 && j<p->nVar && p->azVar[j]!=0 ){    pTos->z = p->azVar[j];    pTos->n = p->anVar[j];    pTos->flags = MEM_Str | MEM_Static;  }else{    pTos->flags = MEM_Null;  }  break;}/* Opcode: Pop P1 * ***** P1 elements are popped off of the top of stack and discarded.*/case OP_Pop: {  assert( pOp->p1>=0 );  popStack(&pTos, pOp->p1);  assert( pTos>=&p->aStack[-1] );  break;}/* Opcode: Dup P1 P2 ***** A copy of the P1-th element of the stack ** is made and pushed onto the top of the stack.** The top of the stack is element 0.  So the** instruction "Dup 0 0 0" will make a copy of the** top of the stack.**** If the content of the P1-th element is a dynamically** allocated string, then a new copy of that string** is made if P2==0.  If P2!=0, then just a pointer** to the string is copied.**** Also see the Pull instruction.*/case OP_Dup: {  Mem *pFrom = &pTos[-pOp->p1];  assert( pFrom<=pTos && pFrom>=p->aStack );  pTos++;  memcpy(pTos, pFrom, sizeof(*pFrom)-NBFS);  if( pTos->flags & MEM_Str ){    if( pOp->p2 && (pTos->flags & (MEM_Dyn|MEM_Ephem)) ){      pTos->flags &= ~MEM_Dyn;      pTos->flags |= MEM_Ephem;    }else if( pTos->flags & MEM_Short ){      memcpy(pTos->zShort, pFrom->zShort, pTos->n);      pTos->z = pTos->zShort;    }else if( (pTos->flags & MEM_Static)==0 ){      pTos->z = sqliteMallocRaw(pFrom->n);      if( sqlite_malloc_failed ) goto no_mem;      memcpy(pTos->z, pFrom->z, pFrom->n);      pTos->flags &= ~(MEM_Static|MEM_Ephem|MEM_Short);      pTos->flags |= MEM_Dyn;    }  }  break;}/* Opcode: Pull P1 * ***** The P1-th element is removed from its current location on ** the stack and pushed back on top of the stack.  The** top of the stack is element 0, so "Pull 0 0 0" is** a no-op.  "Pull 1 0 0" swaps the top two elements of** the stack.**** See also the Dup instruction.*/case OP_Pull: {  Mem *pFrom = &pTos[-pOp->p1];  int i;  Mem ts;  ts = *pFrom;  Deephemeralize(pTos);  for(i=0; i<pOp->p1; i++, pFrom++){    Deephemeralize(&pFrom[1]);    *pFrom = pFrom[1];    assert( (pFrom->flags & MEM_Ephem)==0 );    if( pFrom->flags & MEM_Short ){      assert( pFrom->flags & MEM_Str );      assert( pFrom->z==pFrom[1].zShort );      pFrom->z = pFrom->zShort;    }  }  *pTos = ts;  if( pTos->flags & MEM_Short ){    assert( pTos->flags & MEM_Str );    assert( pTos->z==pTos[-pOp->p1].zShort );    pTos->z = pTos->zShort;  }  break;}/* Opcode: Push P1 * ***** Overwrite the value of the P1-th element down on the** stack (P1==0 is the top of the stack) with the value** of the top of the stack.  Then pop the top of the stack.*/case OP_Push: {  Mem *pTo = &pTos[-pOp->p1];  assert( pTo>=p->aStack );  Deephemeralize(pTos);  Release(pTo);  *pTo = *pTos;  if( pTo->flags & MEM_Short ){    assert( pTo->z==pTos->zShort );    pTo->z = pTo->zShort;  }  pTos--;  break;}/* Opcode: ColumnName P1 P2 P3**** P3 becomes the P1-th column name (first is 0).  An array of pointers** to all column names is passed as the 4th parameter to the callback.** If P2==1 then this is the last column in the result set and thus the** number of columns in the result set will be P1.  There must be at least** one OP_ColumnName with a P2==1 before invoking OP_Callback and the** number of columns specified in OP_Callback must one more than the P1** value of the OP_ColumnName that has P2==1.*/case OP_ColumnName: {  assert( pOp->p1>=0 && pOp->p1<p->nOp );  p->azColName[pOp->p1] = pOp->p3;  p->nCallback = 0;  if( pOp->p2 ) p->nResColumn = pOp->p1+1;  break;}/* Opcode: Callback P1 * ***** Pop P1 values off the stack and form them into an array.  Then** invoke the callback function using the newly formed array as the** 3rd parameter.