BMCPU — C++ Virtual Machine

Forty lines from the archive — the actual main() that instantiates a BMCPU and steps it through a BML application:

{`#define INITGUID
#include <bmvm.h>
#include <stdio.h>
#include <stdlib.h>

DEFINE_GUID( TEST_def,
   0x63CC7777, 0xD99A, 0x11d3, 0xA5, 0x49,
   0x00, 0x10, 0x5A, 0xAB, 0x8B, 0x48 );

void main( void ) {
   BMVM pCPU;
   BMCreateMachine( &pCPU, 0 );
   BMStartApplication( pCPU, &TEST_def );
   BMMachineStep( pCPU, BM_RUN );

   /* Step-into mode with DO/UNDO trace:
   BMTest( pCPU, 1 );
   do {
      UNICHAR szBuffer[1024];
      BMVM_STATE sState;
      sState.dwSize = sizeof( BMVM_STATE );
      BMQueryMachineState( pCPU, &sState );
      PUNICHAR szMode = sState.byMode ? L"UNDO" : L"  DO";
      if( BMQueryInstruction( pCPU, sState.ndxCodeOffset,
                              szBuffer, 1024 ) == BM_SUCCESS ) {
         wprintf( L"%s: %s\\n", szMode, szBuffer );
      }
   } while( BMMachineStep( pCPU, BM_STEP_INTO ) == BM_SUCCESS );
   BMDestroyMachine( pCPU, 0 );
   */
}`}
          

Read this carefully and four design choices appear. Applications are addressed by DEFINE_GUID — COM-addressable, system-registry-discoverable. The public API uses opaque BMVM handles, not C++ inheritance — language-portable. Stepping modes are first-class: BM_RUN for fast execution, BM_STEP_INTO for the debugger trace shown in the comment block. And the commented trace loop reads sState.byMode to print DO or UNDO for every instruction — the speculation phase made visible to the developer.