// interpret.cc - Code for the interpreter

/* Copyright (C) 1999  Cygnus Solutions

   This file is part of libgcj.

This software is copyrighted work licensed under the terms of the
Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
details.  */

/* Author: Kresten Krab Thorup <krab@gnu.org>  */

#include <config.h>

#pragma implementation "java-interp.h"

#include <cni.h>
#include <jvm.h>
#include <java-field.h>
#include <java-cpool.h>
#include <java-interp.h>
#include <java/lang/fdlibm.h>
#include <java/lang/System.h>
#include <java/lang/String.h>
#include <java/lang/Integer.h>
#include <java/lang/StringBuffer.h>
#include <java/io/PrintStream.h>
#include <java/lang/Class.h>
#include <java/lang/reflect/Modifier.h>
#include <java/lang/ClassCastException.h>
#include <java/lang/VirtualMachineError.h>
#include <java/lang/InternalError.h>
#include <java/lang/NullPointerException.h>
#include <java/lang/ArithmeticException.h>
#include <java/lang/IncompatibleClassChangeError.h>
#include <java-insns.h>
#include <java-signal.h>

#ifndef INTERPRETER

#include <gnu/gcj/runtime/MethodInvocation.h>

/* This should never happen. */
void 
gnu::gcj::runtime::MethodInvocation::continue1 (gnu::gcj::RawData *,
						gnu::gcj::RawData *)
{
  JvFail ("no interpreter");
}

#else

#define ClassError _CL_Q34java4lang5Error
extern java::lang::Class ClassError;

static const int PUBLIC       = 0x001;
static const int PRIVATE      = 0x002;
static const int PROTECTED    = 0x004;
static const int STATIC       = 0x008;
static const int FINAL        = 0x010;
static const int SYNCHRONIZED = 0x020;
static const int VOLATILE     = 0x040;
static const int TRANSIENT    = 0x080;
static const int NATIVE       = 0x100;
static const int INTERFACE    = 0x200;
static const int ABSTRACT     = 0x400;
static const int ALL_FLAGS    = 0x7FF; 

static _Jv_Utf8Const *init_name = _Jv_makeUtf8Const ("<init>", 6);

static void throw_internal_error (char *msg)
  __attribute__ ((__noreturn__));
static void throw_incompatible_class_change_error (jstring msg)
  __attribute__ ((__noreturn__));
#if !HANDLE_SEGV
static void throw_null_pointer_exception ()
  __attribute__ ((__noreturn__));
#endif
#if !HANDLE_FPE
static void throw_arithmetic_exception ()
  __attribute__ ((__noreturn__));
#endif


static inline void dupx (_Jv_word *sp, int n, int x)
{
  // first "slide" n+x elements n to the right
  int top = n-1;
  for (int i = 0; i < n+x; i++)
    {
      sp[(top-i)] = sp[(top-i)-n];
    }
  
  // next, copy the n top elements, n+x down
  for (int i = 0; i < n; i++)
    {
      sp[top-(n+x)-i] = sp[top-i];
    }
  
};


#define PUSHA(V)  (sp++)->o = (V)
#define PUSHI(V)  (sp++)->i = (V)
#define PUSHF(V)  (sp++)->f = (V)
#define PUSHL(V)  ({ _Jv_word2 w2; w2.l=(V); \
                     (sp++)->ia[0] = w2.ia[0]; \
                     (sp++)->ia[0] = w2.ia[1]; })
#define PUSHD(V)  ({ _Jv_word2 w2; w2.d=(V); \
                     (sp++)->ia[0] = w2.ia[0]; \
                     (sp++)->ia[0] = w2.ia[1]; })

#define POPA()    ((--sp)->o)
#define POPI()    ((jint) (--sp)->i) // cast since it may be promoted
#define POPF()    ((jfloat) (--sp)->f)
#define POPL()    ({ _Jv_word2 w2; \
                     w2.ia[1] = (--sp)->ia[0]; \
                     w2.ia[0] = (--sp)->ia[0]; w2.l; })
#define POPD()    ({ _Jv_word2 w2; \
                     w2.ia[1] = (--sp)->ia[0]; \
                     w2.ia[0] = (--sp)->ia[0]; w2.d; })

#define LOADA(I)  (sp++)->o = locals[I].o
#define LOADI(I)  (sp++)->i = locals[I].i
#define LOADF(I)  (sp++)->f = locals[I].f
#define LOADL(I)  ({ jint __idx = (I); \
    (sp++)->ia[0] = locals[__idx].ia[0]; \
    (sp++)->ia[0] = locals[__idx+1].ia[0]; \
 })
#define LOADD(I)  LOADL(I)


#define STOREA(I) locals[I].o = (--sp)->o
#define STOREI(I) locals[I].i = (--sp)->i
#define STOREF(I) locals[I].f = (--sp)->f
#define STOREL(I) ({ jint __idx = (I); \
    locals[__idx+1].ia[0] = (--sp)->ia[0]; \
    locals[__idx].ia[0] = (--sp)->ia[0]; \
 })
#define STORED(I) STOREL(I)

#define PEEKI(I)  (locals+(I))->i
#define PEEKA(I)  (locals+(I))->o

#define POKEI(I,V)  ((locals+(I))->i = (V))


#define BINOPI(OP) { \
   jint value2 = POPI(); \
   jint value1 = POPI(); \
   PUSHI(value1 OP value2); \
}

#define BINOPF(OP) { \
   jfloat value2 = POPF(); \
   jfloat value1 = POPF(); \
   PUSHF(value1 OP value2); \
}

#define BINOPL(OP) { \
   jlong value2 = POPL(); \
   jlong value1 = POPL(); \
   PUSHL(value1 OP value2); \
}

#define BINOPD(OP) { \
   jdouble value2 = POPD(); \
   jdouble value1 = POPD(); \
   PUSHD(value1 OP value2); \
}

static inline jint get1s(unsigned char* loc) {
  return *(signed char*)loc;
}

static inline jint get1u(unsigned char* loc) {
  return *loc;
}

static inline jint get2s(unsigned char* loc) {
  return (((jint)*(signed char*)loc) << 8) | ((jint)*(loc+1));
}

static inline jint get2u(unsigned char* loc) {
  return (((jint)(*loc)) << 8) | ((jint)*(loc+1));
}

static jint get4(unsigned char* loc) {
  return (((jint)(loc[0])) << 24) 
       | (((jint)(loc[1])) << 16) 
       | (((jint)(loc[2])) << 8) 
       | (((jint)(loc[3])) << 0);
}


#if HANDLE_SEGV
#define NULLCHECK(X) 
#else
#define NULLCHECK(X) \
  do { if ((X)==NULL) throw_null_pointer_exception (); } while (0)
#endif

#if HANDLE_FPE
#define ZEROCHECK(X)
#else
#define ZEROCHECK(X) \
  do { if ((X) == 0) throw_arithmetic_exception (); } while (0)
#endif

// this method starts the actual running of the method.  It is inlined
// in three different variants in the static methods run_normal,
// run_sync_object and run_sync_class (see below).  Those static methods
// are installed directly in the stub for this method (by
// _Jv_InterpMethod::ncode, in resolve.cc).

inline jobject
_Jv_InterpMethod::run (ffi_cif* cif,
		       void *retp,
		       ffi_raw *args,
		       _Jv_InterpMethodInvocation *inv)
{
  inv->running  = this;
  inv->pc       = bytecode ();
  inv->sp       = inv->stack_base ();
  _Jv_word *locals = inv->local_base ();

  /* Go straight at it!  the ffi raw format matches the internal
     stack representation exactly.  At leat, that's the idea.
  */
  memcpy ((void*) locals, (void*) args, args_raw_size);

 next_segment:
  /* this will call the method _Jv_InterpMethod::continue0, see below */
  jobject ex = 
    gnu::gcj::runtime::MethodInvocation::continue0
    ((gnu::gcj::RawData *)this, (gnu::gcj::RawData *)inv);

  if (ex == 0)			// no exception...
    {
      /* define sp locally, so the POP? macros will pick it up */
      _Jv_word *sp = inv->sp;
      int rtype = cif->rtype->type;

      if (rtype == FFI_TYPE_POINTER)
	{
	  jobject r = POPA();
	  *(jobject*) retp = r;
	  return 0;
	}
      else if (rtype == FFI_TYPE_SINT32)
	{
	  jint r = POPI();
	  *(jint*)retp = r;
	  return 0;
	}
      else if (rtype == FFI_TYPE_VOID)
	{
	  return 0;
	}
      else switch (rtype)
	{
	case FFI_TYPE_FLOAT:
	  {
	    jfloat r = POPF();
	    *(jfloat*)retp = r;
	    return 0;
	  }
      
	case FFI_TYPE_DOUBLE:
	  {
	    jdouble r = POPD();
	    *(jdouble*)retp = r;
	    return 0;
	  }

	case FFI_TYPE_UINT8:
	case FFI_TYPE_UINT16:
	case FFI_TYPE_UINT32:
	case FFI_TYPE_SINT8:
	case FFI_TYPE_SINT16:
	  {
	    jint r = POPI();
	    *(jint*)retp = r;
	    return 0;
	  }
      
	case FFI_TYPE_SINT64:
	  {
	    jlong r = POPL();
	    *(jlong*)retp = r;
	    return 0;
	  }
	
	default:
	  throw_internal_error ("unknown return type");
	}

    }

  /** handle an exception */
  if ( find_exception (ex, inv) )
    goto next_segment;

  java::lang::System::out->println 
    (_Jv_NewStringUTF (self->name->data));

  return ex;
}

bool _Jv_InterpMethod::find_exception (jobject ex,
				       _Jv_InterpMethodInvocation *inv)
{
  int logical_pc = inv->pc - bytecode ();
  _Jv_InterpException *exc = exceptions ();
  jclass exc_class = ex->getClass ();

  for (int i = 0; i < exc_count; i++)
    {
      if (exc[i].start_pc <= logical_pc && logical_pc < exc[i].end_pc)
	{	
	  jclass handler;

	  if (exc[i].handler_type != 0)
	    handler = (_Jv_ResolvePoolEntry (defining_class, 
					     exc[i].handler_type)).clazz;
	  else
	    handler = NULL;
	  
	  if (handler==NULL || handler->isAssignableFrom (exc_class))
	    {
	      inv->pc = bytecode () + exc[i].handler_pc;
	      inv->sp = inv->stack_base (); // reset stack
	      (inv->sp++)->o = ex; // push exception
	      return true;
	    }
	}
    }
  return false;
}

void _Jv_InterpMethod::run_normal (ffi_cif* cif,
				   void* ret,
				   ffi_raw * args,
				   void* __this)
{
  _Jv_InterpMethod* _this = (_Jv_InterpMethod*)__this;

  // we do the alloca of the method invocation here, to allow the method
  // "run" ro be inlined.  Otherwise gcc will ignore the inline directive.
  int storage_size = _this->max_stack+_this->max_locals;
  _Jv_InterpMethodInvocation* inv = (_Jv_InterpMethodInvocation*) 
    alloca (sizeof (_Jv_InterpMethodInvocation)
	    + storage_size * sizeof (_Jv_word));

  jobject ex = _this->run (cif, ret, args, inv);
  if (ex != 0) _Jv_Throw (ex);
}

void _Jv_InterpMethod::run_synch_object (ffi_cif* cif,
					 void* ret,
					 ffi_raw * args,
					 void* __this)
{
  _Jv_InterpMethod* _this = (_Jv_InterpMethod*)__this;
  jobject rcv = (jobject)args[0].ptr;

  int storage_size = _this->max_stack+_this->max_locals;
  _Jv_InterpMethodInvocation* inv = (_Jv_InterpMethodInvocation*) 
    alloca (sizeof (_Jv_InterpMethodInvocation)
	    + storage_size * sizeof (_Jv_word));

  _Jv_MonitorEnter (rcv);
  jobject ex = _this->run (cif, ret, args, inv);
  _Jv_MonitorExit (rcv);

  if (ex != 0) _Jv_Throw (ex);
}

void _Jv_InterpMethod::run_synch_class (ffi_cif* cif,
					void* ret,
					ffi_raw * args,
					void* __this)
{
  _Jv_InterpMethod* _this = (_Jv_InterpMethod*)__this;
  jclass  sync = _this->defining_class;

  int storage_size = _this->max_stack+_this->max_locals;
  _Jv_InterpMethodInvocation* inv = (_Jv_InterpMethodInvocation*) 
    alloca (sizeof (_Jv_InterpMethodInvocation)
	    + storage_size * sizeof (_Jv_word));

  _Jv_MonitorEnter (sync);
  jobject ex = _this->run (cif, ret, args, inv);
  _Jv_MonitorExit (sync);

  if (ex != 0) _Jv_Throw (ex);
}

/* this is the exception handler hack, for the interpreter */
void 
gnu::gcj::runtime::MethodInvocation::continue1 (gnu::gcj::RawData *meth,
						gnu::gcj::RawData *inv)
{
  _Jv_InterpMethod           *meth0 = (_Jv_InterpMethod*)meth;
  _Jv_InterpMethodInvocation *inv0  = (_Jv_InterpMethodInvocation*)inv;
  meth0->continue1 (inv0);
}

/*
  This proceeds execution, as designated in "inv".  If an exception
  happens, then it is simply thrown, and handled in Java.  Thus, the pc
  needs to be stored in the inv->pc at all times, so we can figure
  out which handler (if any) to invoke.

  One design issue, which I have not completely considered, is if it
  should be possible to have interpreted classes linked in!  Seldom used
  (or non-critical) classes could reasonably be interpreted.  
*/


#ifdef __i386__
#define PC_REGISTER_ASM  asm("%esi")
#else
#define PC_REGISTER_ASM
#endif

void _Jv_InterpMethod::continue1 (_Jv_InterpMethodInvocation *inv)
{
  register _Jv_word      *sp                  = inv->sp;
  register unsigned char *pc PC_REGISTER_ASM  = inv->pc;
  _Jv_word               *locals              = inv->local_base ();

  _Jv_word *pool_data   = defining_class->constants.data;
  
  /* these two are used in the invokeXXX instructions */
  void (*fun)(...);
  _Jv_ResolvedMethod* rmeth;

#define INSN_LABEL(op) &&insn_##op
#define GOTO_INSN(op) goto *(insn_target[op])

  static const void *const insn_target[] = 
  {
    INSN_LABEL(nop),
    INSN_LABEL(aconst_null),
    INSN_LABEL(iconst_m1),
    INSN_LABEL(iconst_0),
    INSN_LABEL(iconst_1),
    INSN_LABEL(iconst_2),
    INSN_LABEL(iconst_3),
    INSN_LABEL(iconst_4),
    INSN_LABEL(iconst_5),
    INSN_LABEL(lconst_0),
    INSN_LABEL(lconst_1),
    INSN_LABEL(fconst_0),
    INSN_LABEL(fconst_1),
    INSN_LABEL(fconst_2),
    INSN_LABEL(dconst_0),
    INSN_LABEL(dconst_1),
    INSN_LABEL(bipush),
    INSN_LABEL(sipush),
    INSN_LABEL(ldc),
    INSN_LABEL(ldc_w),
    INSN_LABEL(ldc2_w),
    INSN_LABEL(iload),
    INSN_LABEL(lload),
    INSN_LABEL(fload),
    INSN_LABEL(dload),
    INSN_LABEL(aload),
    INSN_LABEL(iload_0),
    INSN_LABEL(iload_1),
    INSN_LABEL(iload_2),
    INSN_LABEL(iload_3),
    INSN_LABEL(lload_0),
    INSN_LABEL(lload_1),
    INSN_LABEL(lload_2),
    INSN_LABEL(lload_3),
    INSN_LABEL(fload_0),
    INSN_LABEL(fload_1),
    INSN_LABEL(fload_2),
    INSN_LABEL(fload_3),
    INSN_LABEL(dload_0),
    INSN_LABEL(dload_1),
    INSN_LABEL(dload_2),
    INSN_LABEL(dload_3),
    INSN_LABEL(aload_0),
    INSN_LABEL(aload_1),
    INSN_LABEL(aload_2),
    INSN_LABEL(aload_3),
    INSN_LABEL(iaload),
    INSN_LABEL(laload),
    INSN_LABEL(faload),
    INSN_LABEL(daload),
    INSN_LABEL(aaload),
    INSN_LABEL(baload),
    INSN_LABEL(caload),
    INSN_LABEL(saload),
    INSN_LABEL(istore),
    INSN_LABEL(lstore),
    INSN_LABEL(fstore),
    INSN_LABEL(dstore),
    INSN_LABEL(astore),
    INSN_LABEL(istore_0),
    INSN_LABEL(istore_1),
    INSN_LABEL(istore_2),
    INSN_LABEL(istore_3),
    INSN_LABEL(lstore_0),
    INSN_LABEL(lstore_1),
    INSN_LABEL(lstore_2),
    INSN_LABEL(lstore_3),
    INSN_LABEL(fstore_0),
    INSN_LABEL(fstore_1),
    INSN_LABEL(fstore_2),
    INSN_LABEL(fstore_3),
    INSN_LABEL(dstore_0),
    INSN_LABEL(dstore_1),
    INSN_LABEL(dstore_2),
    INSN_LABEL(dstore_3),
    INSN_LABEL(astore_0),
    INSN_LABEL(astore_1),
    INSN_LABEL(astore_2),
    INSN_LABEL(astore_3),
    INSN_LABEL(iastore),
    INSN_LABEL(lastore),
    INSN_LABEL(fastore),
    INSN_LABEL(dastore),
    INSN_LABEL(aastore),
    INSN_LABEL(bastore),
    INSN_LABEL(castore),
    INSN_LABEL(sastore),
    INSN_LABEL(pop),
    INSN_LABEL(pop2),
    INSN_LABEL(dup),
    INSN_LABEL(dup_x1),
    INSN_LABEL(dup_x2),
    INSN_LABEL(dup2),
    INSN_LABEL(dup2_x1),
    INSN_LABEL(dup2_x2),
    INSN_LABEL(swap),
    INSN_LABEL(iadd),
    INSN_LABEL(ladd),
    INSN_LABEL(fadd),
    INSN_LABEL(dadd),
    INSN_LABEL(isub),
    INSN_LABEL(lsub),
    INSN_LABEL(fsub),
    INSN_LABEL(dsub),
    INSN_LABEL(imul),
    INSN_LABEL(lmul),
    INSN_LABEL(fmul),
    INSN_LABEL(dmul),
    INSN_LABEL(idiv),
    INSN_LABEL(ldiv),
    INSN_LABEL(fdiv),
    INSN_LABEL(ddiv),
    INSN_LABEL(irem),
    INSN_LABEL(lrem),
    INSN_LABEL(frem),
    INSN_LABEL(drem),
    INSN_LABEL(ineg),
    INSN_LABEL(lneg),
    INSN_LABEL(fneg),
    INSN_LABEL(dneg),
    INSN_LABEL(ishl),
    INSN_LABEL(lshl),
    INSN_LABEL(ishr),
    INSN_LABEL(lshr),
    INSN_LABEL(iushr),
    INSN_LABEL(lushr),
    INSN_LABEL(iand),
    INSN_LABEL(land),
    INSN_LABEL(ior),
    INSN_LABEL(lor),
    INSN_LABEL(ixor),
    INSN_LABEL(lxor),
    INSN_LABEL(iinc),
    INSN_LABEL(i2l),
    INSN_LABEL(i2f),
    INSN_LABEL(i2d),
    INSN_LABEL(l2i),
    INSN_LABEL(l2f),
    INSN_LABEL(l2d),
    INSN_LABEL(f2i),
    INSN_LABEL(f2l),
    INSN_LABEL(f2d),
    INSN_LABEL(d2i),
    INSN_LABEL(d2l),
    INSN_LABEL(d2f),
    INSN_LABEL(i2b),
    INSN_LABEL(i2c),
    INSN_LABEL(i2s),
    INSN_LABEL(lcmp),
    INSN_LABEL(fcmpl),
    INSN_LABEL(fcmpg),
    INSN_LABEL(dcmpl),
    INSN_LABEL(dcmpg),
    INSN_LABEL(ifeq),
    INSN_LABEL(ifne),
    INSN_LABEL(iflt),
    INSN_LABEL(ifge),
    INSN_LABEL(ifgt),
    INSN_LABEL(ifle),
    INSN_LABEL(if_icmpeq),
    INSN_LABEL(if_icmpne),
    INSN_LABEL(if_icmplt),
    INSN_LABEL(if_icmpge),
    INSN_LABEL(if_icmpgt),
    INSN_LABEL(if_icmple),
    INSN_LABEL(if_acmpeq),
    INSN_LABEL(if_acmpne),
    INSN_LABEL(goto), 
    INSN_LABEL(jsr),
    INSN_LABEL(ret),
    INSN_LABEL(tableswitch),
    INSN_LABEL(lookupswitch),
    INSN_LABEL(ireturn),
    INSN_LABEL(lreturn),
    INSN_LABEL(freturn),
    INSN_LABEL(dreturn),
    INSN_LABEL(areturn),
    INSN_LABEL(return),
    INSN_LABEL(getstatic),
    INSN_LABEL(putstatic),
    INSN_LABEL(getfield),
    INSN_LABEL(putfield),
    INSN_LABEL(invokevirtual),
    INSN_LABEL(invokespecial),
    INSN_LABEL(invokestatic),
    INSN_LABEL(invokeinterface),
    0, /* op_xxxunusedxxx1, */
    INSN_LABEL(new),
    INSN_LABEL(newarray),
    INSN_LABEL(anewarray),
    INSN_LABEL(arraylength),
    INSN_LABEL(athrow),
    INSN_LABEL(checkcast),
    INSN_LABEL(instanceof),
    INSN_LABEL(monitorenter),
    INSN_LABEL(monitorexit),
    INSN_LABEL(wide),
    INSN_LABEL(multianewarray),
    INSN_LABEL(ifnull),
    INSN_LABEL(ifnonnull),
    INSN_LABEL(goto_w),
    INSN_LABEL(jsr_w),

    INSN_LABEL(putfield_1),
    INSN_LABEL(putfield_2),
    INSN_LABEL(putfield_4),
    INSN_LABEL(putfield_8),
    INSN_LABEL(putfield_a),

    INSN_LABEL(putstatic_1),
    INSN_LABEL(putstatic_2),
    INSN_LABEL(putstatic_4),
    INSN_LABEL(putstatic_8),
    INSN_LABEL(putstatic_a),

    INSN_LABEL(getfield_1),
    INSN_LABEL(getfield_2s),
    INSN_LABEL(getfield_2u),
    INSN_LABEL(getfield_4),
    INSN_LABEL(getfield_8),
    INSN_LABEL(getfield_a),

    INSN_LABEL(getstatic_1),
    INSN_LABEL(getstatic_2s),
    INSN_LABEL(getstatic_2u),
    INSN_LABEL(getstatic_4),
    INSN_LABEL(getstatic_8),
    INSN_LABEL(getstatic_a),
  };

#define SAVE_PC   inv->pc = pc-1

  /* If the macro INLINE_SWITCH is not defined, then the main loop
     operates as one big (normal) switch statement.  If it is defined,
     then the case selection is performed `inline' in the end of the
     code for each case.  The latter saves a native branch instruction
     for each java-instruction, but expands the code size somewhat.

     NOTE: On i386 defining INLINE_SWITCH improves over all
     performance approximately seven percent, but it may be different
     for other machines.  At some point, this may be made into a proper
     configuration parameter.  */

#define INLINE_SWITCH 

#ifdef  INLINE_SWITCH

#define NEXT_INSN GOTO_INSN(*pc++)
  NEXT_INSN;
#else

#define NEXT_INSN goto next_insn

 next_insn:
  GOTO_INSN (*pc++);

#endif

  /* The first few instructions here are ordered according to their
     frequency, in the hope that this will improve code locality a
     little.  */

     insn_aload_0:		// 0x2a
      LOADA(0);
      NEXT_INSN;

     insn_iload:		// 0x15
      LOADI (get1u (pc++));
      NEXT_INSN;

     insn_getfield_4:		// 0xd8
      SAVE_PC;
      {
	jobject obj   = POPA();
	NULLCHECK(obj);
	jint field_offset = get2u (pc); pc += 2;
	PUSHI (*(jint*) ((char*)obj + field_offset));
      }
      NEXT_INSN;

     insn_iload_1:		// 0x1b
      LOADI (1);
      NEXT_INSN;

     insn_getfield_a:		// 0xda
      SAVE_PC;
      {
	jobject obj   = POPA();
	NULLCHECK(obj);
	jint field_offset = get2u (pc); pc += 2;
	PUSHA(*(jobject*) ((char*)obj + field_offset));
      }
      NEXT_INSN;

     insn_invokevirtual:	// 0xb6
      SAVE_PC;
      {
	int index = get2u (pc); pc += 2;

	/* _Jv_ResolvePoolEntry returns immediately if the value already
	 * is resolved.  If we want to clutter up the code here to gain
	 * a little performance, then we can check the corresponding bit
	 * JV_CONSTANT_ResolvedFlag in the tag directly.  For now, I
	 * don't think it is worth it.  */

	rmeth = (_Jv_ResolvePoolEntry (defining_class, index)).rmethod;

	sp -= rmeth->stack_item_count;
	NULLCHECK(sp[0]);

	if (rmeth->vtable_index == -1)
	  {
	    // final methods do not appear in the vtable,
	    // if it does not appear in the superclass.
	    fun = (void (*) (...)) rmeth->method->ncode;
	  }
	else
	  {
	    jobject rcv = sp[0].o;
	    _Jv_VTable *table = *(_Jv_VTable**)rcv;
	    fun = (void (*) (...))table->method[rmeth->vtable_index];
	  }
      }
      goto perform_invoke;

     perform_invoke:
      {
	/* here goes the magic again... */
	ffi_cif *cif = &rmeth->cif;
	ffi_raw *raw = (ffi_raw*) sp;

	jdouble rvalue;

	ffi_raw_call (cif, fun, (void*)&rvalue, raw);

	int rtype = cif->rtype->type;

	/* the likelyhood of object, int, or void return is very high,
	 * so those are checked before the switch */
	if (rtype == FFI_TYPE_POINTER)
	  {
	    PUSHA (*(jobject*)&rvalue);
	  }
	else if (rtype == FFI_TYPE_SINT32)
	  {
	    PUSHI (*(jint*)&rvalue);
	  }
	else if (rtype == FFI_TYPE_VOID)
	  {
	    /* skip */
	  }
	else switch (rtype) 
	  {
	  case FFI_TYPE_SINT8:
	    {
	      jbyte value = (*(jint*)&rvalue) & 0xff;
	      PUSHI (value);
	    }
	    break;

	  case FFI_TYPE_SINT16:
	    {
	      jshort value = (*(jint*)&rvalue) & 0xffff;
	      PUSHI (value);
	    }
	    break;

	  case FFI_TYPE_UINT16:
	    {
	      jint value = (*(jint*)&rvalue) & 0xffff;
	      PUSHI (value);
	    }
	    break;

	  case FFI_TYPE_FLOAT:
	    PUSHF (*(jfloat*)&rvalue);
	    break;

	  case FFI_TYPE_DOUBLE:
	    PUSHD (rvalue);
	    break;

	  case FFI_TYPE_SINT64:
	    PUSHL (*(jlong*)&rvalue);
	    break;

	  default:
	    throw_internal_error ("unknown return type in invokeXXX");
	  }

      }
      NEXT_INSN;


     insn_nop:
      NEXT_INSN;

     insn_aconst_null:
      PUSHA (NULL);
      NEXT_INSN;

     insn_iconst_m1:
      PUSHI (-1);
      NEXT_INSN;

     insn_iconst_0:
      PUSHI (0);
      NEXT_INSN;

     insn_iconst_1:
      PUSHI (1);
      NEXT_INSN;

     insn_iconst_2:
      PUSHI (2);
      NEXT_INSN;

     insn_iconst_3:
      PUSHI (3);
      NEXT_INSN;

     insn_iconst_4:
      PUSHI (4);
      NEXT_INSN;

     insn_iconst_5:
      PUSHI (5);
      NEXT_INSN;

     insn_lconst_0:
      PUSHL (0);
      NEXT_INSN;

     insn_lconst_1:
      PUSHL (1);
      NEXT_INSN;

     insn_fconst_0:
      PUSHF (0);
      NEXT_INSN;

     insn_fconst_1:
      PUSHF (1);
      NEXT_INSN;

     insn_fconst_2:
      PUSHF (2);
      NEXT_INSN;

     insn_dconst_0:
      PUSHD (0);
      NEXT_INSN;

     insn_dconst_1:
      PUSHD (1);
      NEXT_INSN;

     insn_bipush:
      PUSHI (get1s(pc++));
      NEXT_INSN;

     insn_sipush:
      PUSHI (get2s(pc)); pc += 2;
      NEXT_INSN;

     insn_ldc:
      {
	int index = get1u (pc++);
	PUSHA(pool_data[index].o);
      }
      NEXT_INSN;

     insn_ldc_w:
      {
	int index = get2u (pc); pc += 2;
	PUSHA(pool_data[index].o);
      }
      NEXT_INSN;

     insn_ldc2_w:
      {
	int index = get2u (pc); pc += 2;
	memcpy (sp, &pool_data[index], 2*sizeof (_Jv_word));
	sp += 2;
      }
      NEXT_INSN;

     insn_lload:
      LOADL (get1u (pc++));
      NEXT_INSN;

     insn_fload:
      LOADF (get1u (pc++));
      NEXT_INSN;

     insn_dload:
      LOADD (get1u (pc++));
      NEXT_INSN;

     insn_aload:
      LOADA (get1u (pc++));
      NEXT_INSN;

     insn_iload_0:
      LOADI (0);
      NEXT_INSN;

     insn_iload_2:
      LOADI (2);
      NEXT_INSN;

     insn_iload_3:
      LOADI (3);
      NEXT_INSN;

     insn_lload_0:
      LOADL (0);
      NEXT_INSN;

     insn_lload_1:
      LOADL (1);
      NEXT_INSN;

     insn_lload_2:
      LOADL (2);
      NEXT_INSN;

     insn_lload_3:
      LOADL (3);
      NEXT_INSN;

     insn_fload_0:
      LOADF (0);
      NEXT_INSN;

     insn_fload_1:
      LOADF (1);
      NEXT_INSN;

     insn_fload_2:
      LOADF (2);
      NEXT_INSN;

     insn_fload_3:
      LOADF (3);
      NEXT_INSN;

     insn_dload_0:
      LOADD (0);
      NEXT_INSN;

     insn_dload_1:
      LOADD (1);
      NEXT_INSN;

     insn_dload_2:
      LOADD (2);
      NEXT_INSN;

     insn_dload_3:
      LOADD (3);
      NEXT_INSN;

     insn_aload_1:
      LOADA(1);
      NEXT_INSN;

     insn_aload_2:
      LOADA(2);
      NEXT_INSN;

     insn_aload_3:
      LOADA(3);
      NEXT_INSN;

     insn_iaload:
      SAVE_PC;
      {
	jint index = POPI();
	jintArray arr = (jintArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	PUSHI( elements(arr)[index] );
      }
      NEXT_INSN;

     insn_laload:
      SAVE_PC;
      {
	jint index = POPI();
	jlongArray arr = (jlongArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	PUSHL( elements(arr)[index] );
      }
      NEXT_INSN;

     insn_faload:
      SAVE_PC;
      {
	jint index = POPI();
	jfloatArray arr = (jfloatArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	PUSHF( elements(arr)[index] );
      }
      NEXT_INSN;

     insn_daload:
      SAVE_PC;
      {
	jint index = POPI();
	jdoubleArray arr = (jdoubleArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	PUSHD( elements(arr)[index] );
      }
      NEXT_INSN;

     insn_aaload:
      SAVE_PC;
      {
	jint index = POPI();
	jobjectArray arr = (jobjectArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	PUSHA( elements(arr)[index] );
      }
      NEXT_INSN;

     insn_baload:
      SAVE_PC;
      {
	jint index = POPI();
	jbyteArray arr = (jbyteArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	PUSHI( elements(arr)[index] );
      }
      NEXT_INSN;

     insn_caload:
      SAVE_PC;
      {
	jint index = POPI();
	jcharArray arr = (jcharArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	PUSHI( elements(arr)[index] );
      }
      NEXT_INSN;

     insn_saload:
      SAVE_PC;
      {
	jint index = POPI();
	jshortArray arr = (jshortArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	PUSHI( elements(arr)[index] );
      }
      NEXT_INSN;

     insn_istore:
      STOREI (get1u (pc++));
      NEXT_INSN;

     insn_lstore:
      STOREL (get1u (pc++));
      NEXT_INSN;

     insn_fstore:
      STOREF (get1u (pc++));
      NEXT_INSN;

     insn_dstore:
      STORED (get1u (pc++));
      NEXT_INSN;

     insn_astore:
      STOREI (get1u (pc++));
      NEXT_INSN;

     insn_istore_0:
      STOREI (0);
      NEXT_INSN;

     insn_istore_1:
      STOREI (1);
      NEXT_INSN;

     insn_istore_2:
      STOREI (2);
      NEXT_INSN;

     insn_istore_3:
      STOREI (3);
      NEXT_INSN;

     insn_lstore_0:
      STOREL (0);
      NEXT_INSN;

     insn_lstore_1:
      STOREL (1);
      NEXT_INSN;

     insn_lstore_2:
      STOREL (2);
      NEXT_INSN;

     insn_lstore_3:
      STOREL (3);
      NEXT_INSN;

     insn_fstore_0:
      STOREF (0);
      NEXT_INSN;

     insn_fstore_1:
      STOREF (1);
      NEXT_INSN;

     insn_fstore_2:
      STOREF (2);
      NEXT_INSN;

     insn_fstore_3:
      STOREF (3);
      NEXT_INSN;

     insn_dstore_0:
      STORED (0);
      NEXT_INSN;

     insn_dstore_1:
      STORED (1);
      NEXT_INSN;

     insn_dstore_2:
      STORED (2);
      NEXT_INSN;

     insn_dstore_3:
      STORED (3);
      NEXT_INSN;

     insn_astore_0:
      STOREA(0);
      NEXT_INSN;

     insn_astore_1:
      STOREA(1);
      NEXT_INSN;

     insn_astore_2:
      STOREA(2);
      NEXT_INSN;

     insn_astore_3:
      STOREA(3);
      NEXT_INSN;

     insn_iastore:
      SAVE_PC;
      {
	jint value = POPI();
	jint index  = POPI();
	jintArray arr = (jintArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	elements(arr)[index] = value;
      }
      NEXT_INSN;

     insn_lastore:
      SAVE_PC;
      {
	jlong value = POPL();
	jint index  = POPI();
	jlongArray arr = (jlongArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	elements(arr)[index] = value;
      }
      NEXT_INSN;

     insn_fastore:
      SAVE_PC;
      {
	jfloat value = POPF();
	jint index  = POPI();
	jfloatArray arr = (jfloatArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	elements(arr)[index] = value;
      }
      NEXT_INSN;

     insn_dastore:
      SAVE_PC;
      {
	jdouble value = POPD();
	jint index  = POPI();
	jdoubleArray arr = (jdoubleArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	elements(arr)[index] = value;
      }
      NEXT_INSN;

     insn_aastore:
      SAVE_PC;
      {
	jobject value = POPA();
	jint index  = POPI();
	jobjectArray arr = (jobjectArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	_Jv_CheckArrayStore (arr, value);
	elements(arr)[index] = value;
      }
      NEXT_INSN;

     insn_bastore:
      SAVE_PC;
      {
	jbyte value = (jbyte) POPI();
	jint index  = POPI();
	jbyteArray arr = (jbyteArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	elements(arr)[index] = value;
      }
      NEXT_INSN;

     insn_castore:
      SAVE_PC;
      {
	jchar value = (jchar) POPI();
	jint index  = POPI();
	jcharArray arr = (jcharArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	elements(arr)[index] = value;
      }
      NEXT_INSN;

     insn_sastore:
      SAVE_PC;
      {
	jshort value = (jshort) POPI();
	jint index  = POPI();
	jshortArray arr = (jshortArray) POPA();
	NULLCHECK (arr);
	if (index < 0 || index >= arr->length)
	  {
	    _Jv_ThrowBadArrayIndex (index);
	  }
	elements(arr)[index] = value;
      }
      NEXT_INSN;

     insn_pop:
      sp -= 1;
      NEXT_INSN;

     insn_pop2:
      sp -= 2;
      NEXT_INSN;

     insn_dup:
      sp[0] = sp[-1];
      sp += 1;
      NEXT_INSN;

     insn_dup_x1:
      dupx (sp, 1, 1); sp+=1;
      NEXT_INSN;

     insn_dup_x2:
      dupx (sp, 1, 2); sp+=1;
      NEXT_INSN;

     insn_dup2:
      sp[0] = sp[-2];
      sp[1] = sp[-1];
      sp += 2;
      NEXT_INSN;

     insn_dup2_x1:
      dupx (sp, 2, 1); sp+=2;
      NEXT_INSN;

     insn_dup2_x2:
      dupx (sp, 2, 2); sp+=2;
      NEXT_INSN;

     insn_swap:
      {
	jobject tmp1 = POPA();
	jobject tmp2 = POPA();
	PUSHA (tmp1);
	PUSHA (tmp2);
      }
      NEXT_INSN;

     insn_iadd:
      BINOPI(+);
      NEXT_INSN;

     insn_ladd:
      BINOPL(+);
      NEXT_INSN;

     insn_fadd:
      BINOPF(+);
      NEXT_INSN;

     insn_dadd:
      BINOPD(+);
      NEXT_INSN;

     insn_isub:
      BINOPI(-);
      NEXT_INSN;

     insn_lsub:
      BINOPL(-);
      NEXT_INSN;

     insn_fsub:
      BINOPF(-);
      NEXT_INSN;

     insn_dsub:
      BINOPD(-);
      NEXT_INSN;

     insn_imul:
      BINOPI(*);
      NEXT_INSN;

     insn_lmul:
      BINOPL(*);
      NEXT_INSN;

     insn_fmul:
      BINOPF(*);
      NEXT_INSN;

     insn_dmul:
      BINOPD(*);
      NEXT_INSN;

     insn_idiv:
      SAVE_PC;
      {
	jint value2 = POPI();
	jint value1 = POPI();
	ZEROCHECK (value2);
	jint res = value1 / value2;
	PUSHI (res);
      }
      NEXT_INSN;

     insn_ldiv:
      SAVE_PC;
      {
	jlong value2 = POPL();
	jlong value1 = POPL();
	ZEROCHECK (value2);
	jlong res = value1 / value2;
	PUSHL (res);
      }
      NEXT_INSN;

     insn_fdiv:
      SAVE_PC;
      {
	jfloat value2 = POPF();
	jfloat value1 = POPF();
	ZEROCHECK (value2);
	jfloat res = value1 / value2;
	PUSHF (res);
      }
      NEXT_INSN;

     insn_ddiv:
      SAVE_PC;
      {
	jdouble value2 = POPD();
	jdouble value1 = POPD();
	ZEROCHECK (value2);
	jdouble res = value1 / value2;
	PUSHD (res);
      }
      NEXT_INSN;

     insn_irem:
      SAVE_PC;
      {
	jint value2 = POPI();
	jint value1 = POPI();
	ZEROCHECK (value2);	
	jint res = value1 % value2;
	PUSHI (res);
      }
      NEXT_INSN;

     insn_lrem:
      SAVE_PC;
      {
	jlong value2 = POPL();
	jlong value1 = POPL();
	ZEROCHECK (value2);
	jlong res = value1 % value2;
	PUSHL (res);
      }
      NEXT_INSN;

     insn_frem:
      SAVE_PC;
      {
	jfloat value2 = POPF();
	jfloat value1 = POPF();
	ZEROCHECK (value2);
	jfloat res    = __ieee754_fmod (value1, value2);
	PUSHF (res);
      }
      NEXT_INSN;

     insn_drem:
      SAVE_PC;
      {
	jdouble value2 = POPD();
	jdouble value1 = POPD();
	ZEROCHECK (value2);
	jdouble res    = __ieee754_fmod (value1, value2);
	PUSHD (res);
      }
      NEXT_INSN;

     insn_ineg:
      {
	jint value = POPI();
	PUSHI (value * -1);
      }
      NEXT_INSN;

     insn_lneg:
      {
	jlong value = POPL();
	PUSHL (value * -1);
      }
      NEXT_INSN;

     insn_fneg:
      {
	jfloat value = POPF();
	PUSHF (value * -1);
      }
      NEXT_INSN;

     insn_dneg:
      {
	jdouble value = POPD();
	PUSHD (value * -1);
      }
      NEXT_INSN;

     insn_ishl:
      {
	jint shift = (POPI() & 0x1f);
	jint value = POPI();
	PUSHI (value << shift);
      }
      NEXT_INSN;

     insn_lshl:
      {
	jint shift = (POPI() & 0x3f);
	jlong value = POPL();
	PUSHL (value << shift);
      }
      NEXT_INSN;

     insn_ishr:
      {
	jint shift = (POPI() & 0x1f);
	jint value = POPI();
	PUSHI (value >> shift);
      }
      NEXT_INSN;

     insn_lshr:
      {
	jint shift = (POPI() & 0x3f);
	jlong value = POPL();
	PUSHL (value >> shift);
      }
      NEXT_INSN;

     insn_iushr:
      {
	jint shift = (POPI() & 0x1f);
	unsigned long value = POPI();
	PUSHI ((jint) (value >> shift));
      }
      NEXT_INSN;

     insn_lushr:
      {
	jint shift = (POPI() & 0x3f);
	UINT64 value = (UINT64) POPL();
	PUSHL ((value >> shift));
      }
      NEXT_INSN;

     insn_iand:
      BINOPI (&);
      NEXT_INSN;

     insn_land:
      BINOPL (&);
      NEXT_INSN;

     insn_ior:
      BINOPI (|);
      NEXT_INSN;

     insn_lor:
      BINOPL (|);
      NEXT_INSN;

     insn_ixor:
      BINOPI (^);
      NEXT_INSN;

     insn_lxor:
      BINOPL (^);
      NEXT_INSN;

     insn_iinc:
      {
	jint index  = get1u (pc++);
	jint amount = get1s (pc++);
	locals[index].i += amount;
      }
      NEXT_INSN;

     insn_i2l:
      {jlong value = POPI(); PUSHL (value);}
      NEXT_INSN;

     insn_i2f:
      {jfloat value = POPI(); PUSHF (value);}
      NEXT_INSN;

     insn_i2d:
      {jdouble value = POPI(); PUSHD (value);}
      NEXT_INSN;

     insn_l2i:
      {jint value = POPL(); PUSHI (value);}
      NEXT_INSN;

     insn_l2f:
      {jfloat value = POPL(); PUSHF (value);}
      NEXT_INSN;

     insn_l2d:
      {jdouble value = POPL(); PUSHD (value);}
      NEXT_INSN;

     insn_f2i:
      { jint value = (jint)POPF (); PUSHI(value); }
      NEXT_INSN;

     insn_f2l:
      { jlong value = (jlong)POPF (); PUSHL(value); }
      NEXT_INSN;

     insn_f2d:
      { jdouble value = POPF (); PUSHD(value); }
      NEXT_INSN;

     insn_d2i:
      { jint value = (jint)POPD (); PUSHI(value); }
      NEXT_INSN;

     insn_d2l:
      { jlong value = (jlong)POPD (); PUSHL(value); }
      NEXT_INSN;

     insn_d2f:
      { jfloat value = POPD (); PUSHF(value); }
      NEXT_INSN;

     insn_i2b:
      { jbyte value = POPI (); PUSHI(value); }
      NEXT_INSN;

     insn_i2c:
      { jchar value = POPI (); PUSHI(value); }
      NEXT_INSN;

     insn_i2s:
      { jshort value = POPI (); PUSHI(value); }
      NEXT_INSN;

     insn_lcmp:
      {
	jlong value2 = POPL ();
	jlong value1 = POPL ();
	if (value1 > value2)
	  { PUSHI (1); }
	else if (value1 == value2)
	  { PUSHI (0); }
	else
	  { PUSHI (-1); }
      }
      NEXT_INSN;

     insn_fcmpl:
     insn_fcmpg:
      {
	jfloat value2 = POPF ();
	jfloat value1 = POPF ();
	if (value1 > value2)
	  PUSHI (1);
	else if (value1 == value2)
	  PUSHI (0);
	else if (value1 < value2)
	  PUSHI (-1);
	else if ((*(pc-1)) == op_fcmpg)
	  PUSHI (1);
	else
	  PUSHI (-1);
      }
      NEXT_INSN;

     insn_dcmpl:
     insn_dcmpg:
      {
	jdouble value2 = POPD ();
	jdouble value1 = POPD ();
	if (value1 > value2)
	  PUSHI (1);
	else if (value1 == value2)
	  PUSHI (0);
	else if (value1 < value2)
	  PUSHI (-1);
	else if ((*(pc-1)) == op_dcmpg)
	  PUSHI (1);
	else
	  PUSHI (-1);
      }
      NEXT_INSN;

     insn_ifeq:
      {
	jint offset = get2s (pc); 
	if (POPI() == 0)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_ifne:
      {
	jint offset = get2s (pc); 
	if (POPI() != 0)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_iflt:
      {
	jint offset = get2s (pc); 
	if (POPI() < 0)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_ifge:
      {
	jint offset = get2s (pc); 
	if (POPI() >= 0)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_ifgt:
      {
	jint offset = get2s (pc); 
	if (POPI() > 0)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_ifle:
      {
	jint offset = get2s (pc); 
	if (POPI() <= 0)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_if_icmpeq:
      {
	jint offset = get2s (pc); 
	jint value2 = POPI();
	jint value1 = POPI();
	if (value1 == value2)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_if_icmpne:
      {
	jint offset = get2s (pc); 
	jint value2 = POPI();
	jint value1 = POPI();
	if (value1 != value2)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_if_icmplt:
      {
	jint offset = get2s (pc); 
	jint value2 = POPI();
	jint value1 = POPI();
	if (value1 < value2)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_if_icmpge:
      {
	jint offset = get2s (pc); 
	jint value2 = POPI();
	jint value1 = POPI();
	if (value1 >= value2)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_if_icmpgt:
      {
	jint offset = get2s (pc); 
	jint value2 = POPI();
	jint value1 = POPI();
	if (value1 > value2)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_if_icmple:
      {
	jint offset = get2s (pc); 
	jint value2 = POPI();
	jint value1 = POPI();
	if (value1 <= value2)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_if_acmpeq:
      {
	jint offset = get2s (pc); 
	jobject value2 = POPA();
	jobject value1 = POPA();
	if (value1 == value2)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_if_acmpne:
      {
	jint offset = get2s (pc); 
	jobject value2 = POPA();
	jobject value1 = POPA();
	if (value1 != value2)
	  pc = pc-1+offset;
	else
	  pc = pc+2;
      }
      NEXT_INSN;

     insn_goto: 
      {
	jint offset = get2s (pc);
	pc = pc-1+offset;
      }
      NEXT_INSN;

     insn_jsr:
      {
	unsigned char *base_pc = pc-1;
	jint offset = get2s (pc); pc += 2;
	PUSHA ((jobject)pc);
	pc = base_pc+offset;
      }
      NEXT_INSN;

     insn_ret:
      {
	jint index = get1u (pc);
	pc = (unsigned char*) PEEKA (index);
      }
      NEXT_INSN;

     insn_tableswitch:
      {
	unsigned char *base_pc = pc-1;
	int index = POPI();

	unsigned char* base = bytecode ();
	while ((pc-base) % 4 != 0)
	  pc++;

	jint def     = get4 (pc);
	jint low     = get4 (pc+4);
	jint high    = get4 (pc+8);

	if (index < low || index > high)
	  pc = base_pc + def;    
	else
	  pc = base_pc + get4 (pc+4*(index-low+3));
      }
      NEXT_INSN;

     insn_lookupswitch:
      {
	unsigned char *base_pc = pc-1;
	int index = POPI();

	unsigned char* base = bytecode ();
	while ((pc-base) % 4 != 0)
	  pc++;

	jint def     = get4 (pc);
	jint npairs  = get4 (pc+4);

	int max = npairs-1;
	int min = 0;

	// simple binary search...
	while (min < max)
	  {
	    int half = (min+max)/2;
	    int match = get4 (pc+ 4*(2 + 2*half));

	    if (index == match)
	      min = max = half;

	    else if (index < match)
	      max = half-1;

	    else
	      min = half+1;
	  }

	if (index == get4 (pc+ 4*(2 + 2*min)))
	  pc = base_pc + get4 (pc+ 4*(2 + 2*min + 1));
	else
	  pc = base_pc + def;    
      }
      NEXT_INSN;

      /* on return, just save the sp and return to caller */
     insn_ireturn:
     insn_lreturn:
     insn_freturn:
     insn_dreturn:
     insn_areturn:
     insn_return:
      inv->sp = sp;
      return;

     insn_getstatic:
      SAVE_PC;
      {
	unsigned char *base_pc = pc-1;
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_ResolvePoolEntry (defining_class, fieldref_index);
	_Jv_Field *field = pool_data[fieldref_index].field;

	if ((field->flags & STATIC) == 0)
	  throw_incompatible_class_change_error 
	    (JvNewStringLatin1 ("field no longer static"));

	jclass type = field->type;

	if (type->isPrimitive ())
	  {
	    switch (type->size_in_bytes)
	      {
	      case 1:
		*base_pc = op_getstatic_1;
		break;

	      case 2:
		if (type == JvPrimClass (char))
		  *base_pc = op_getstatic_2u;
		else
		  *base_pc = op_getstatic_2s;
		break;

	      case 4:
		*base_pc = op_getstatic_4;
		break;

	      case 8:
		*base_pc = op_getstatic_8;
		break;
	      }
	  }
	else
	  {
	    *base_pc = op_getstatic_a;
	  }

	pc = base_pc;
      }
      NEXT_INSN;

     insn_getfield:
      SAVE_PC;
      {
	unsigned char *base_pc = pc-1;
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_ResolvePoolEntry (defining_class, fieldref_index);
	_Jv_Field *field = pool_data[fieldref_index].field;

	if ((field->flags & STATIC) != 0)
	  throw_incompatible_class_change_error 
	    (JvNewStringLatin1 ("field is static"));

	jclass type = field->type;

	if (type->isPrimitive ())
	  {
	    switch (type->size_in_bytes)
	      {
	      case 1:
		*base_pc = op_getfield_1;
		break;

	      case 2:
		if (type == JvPrimClass (char))
		  *base_pc = op_getfield_2u;
		else
		  *base_pc = op_getfield_2s;
		break;

	      case 4:
		*base_pc = op_getfield_4;
		break;

	      case 8:
		*base_pc = op_getfield_8;
		break;
	      }
	  }
	else
	  {
	    *base_pc = op_getfield_a;
	  }

	if (field->u.boffset > 0xffff)
	  JvThrow (new java::lang::VirtualMachineError);

	base_pc[1] = (field->u.boffset>>8) & 0xff;
	base_pc[2] = field->u.boffset & 0xff;

	pc = base_pc;
      }
      NEXT_INSN;

     insn_putstatic:
      SAVE_PC;
      {
	unsigned char* base_pc = pc-1;
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_ResolvePoolEntry (defining_class, fieldref_index);
	_Jv_Field *field = pool_data[fieldref_index].field;

	jclass type = field->type;

	// ResolvePoolEntry cannot check this
	if ((field->flags & STATIC) == 0)
	  throw_incompatible_class_change_error 
	    (JvNewStringLatin1 ("field no longer static"));

	/* if this is patented, then maybe we could install
	   a function in the constant pool, to do the right thing */

	if (type->isPrimitive ())
	  {
	    switch (type->size_in_bytes) 
	      {
	      case 1:
		*base_pc = op_putstatic_1;
		break;

	      case 2:
		*base_pc = op_putstatic_2;
		break;

	      case 4:
		*base_pc = op_putstatic_4;
		break;

	      case 8:
		*base_pc = op_putstatic_8;
		break;
	      }
	  }
	else
	  {
	    *base_pc = op_putstatic_a;
	  }

	// do the instruction again!
	pc = base_pc;
      }
      NEXT_INSN;


     insn_putfield:
      SAVE_PC;
      {
	unsigned char* base_pc = pc-1;
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_ResolvePoolEntry (defining_class, fieldref_index);
	_Jv_Field *field = pool_data[fieldref_index].field;

	jclass type = field->type;

	if ((field->flags & STATIC) != 0)
	  throw_incompatible_class_change_error 
	    (JvNewStringLatin1 ("field is static"));

	if (type->isPrimitive ())
	  {
	    switch (type->size_in_bytes) 
	      {
	      case 1:
		*base_pc = op_putfield_1;
		break;

	      case 2:
		*base_pc = op_putfield_2;
		break;

	      case 4:
		*base_pc = op_putfield_4;
		break;

	      case 8:
		*base_pc = op_putfield_8;
		break;
	      }
	  }
	else
	  {
	    *base_pc = op_putfield_a;
	  }

	if (field->u.boffset > 0xffff)
	  JvThrow (new java::lang::VirtualMachineError);

	base_pc[1] = (field->u.boffset>>8) & 0xff;
	base_pc[2] = field->u.boffset & 0xff;

	// do the instruction again!
	pc = base_pc;
      }
      NEXT_INSN;


     insn_getfield_1:
      SAVE_PC;
      {
	jobject obj   = POPA();
	NULLCHECK(obj);
	jint field_offset = get2u (pc); pc += 2;
	PUSHI (*(jbyte*) ((char*)obj + field_offset));
      }
      NEXT_INSN;

     insn_getfield_2s:
      SAVE_PC;
      {
	jobject obj   = POPA();
	NULLCHECK(obj);
	jint field_offset = get2u (pc); pc += 2;
	PUSHI (*(jshort*) ((char*)obj + field_offset));
      }
      NEXT_INSN;

     insn_getfield_2u:
      SAVE_PC;
      {
	jobject obj   = POPA();
	NULLCHECK(obj);
	jint field_offset = get2u (pc); pc += 2;
	PUSHI (*(jchar*) ((char*)obj + field_offset));
      }
      NEXT_INSN;

     insn_getfield_8:
      SAVE_PC;
      {
	jobject obj   = POPA();
	NULLCHECK(obj);
	jint field_offset = get2u (pc); pc += 2;
	PUSHL(*(jlong*) ((char*)obj + field_offset));
      }
      NEXT_INSN;

     insn_getstatic_1:
      {
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_Field *field = pool_data[fieldref_index].field;
	PUSHI (*(jbyte*) (field->u.addr));
      }
      NEXT_INSN;

     insn_getstatic_2s:
      {
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_Field *field = pool_data[fieldref_index].field;
	PUSHI(*(jshort*) (field->u.addr));
      }
      NEXT_INSN;

     insn_getstatic_2u:
      {
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_Field *field = pool_data[fieldref_index].field;
	PUSHI(*(jchar*) (field->u.addr));
      }
      NEXT_INSN;

     insn_getstatic_4:
      {
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_Field *field = pool_data[fieldref_index].field;
	PUSHI(*(jint*) (field->u.addr));
      }
      NEXT_INSN;

     insn_getstatic_8:
      {
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_Field *field = pool_data[fieldref_index].field;
	PUSHL(*(jlong*) (field->u.addr));
      }
      NEXT_INSN;

     insn_getstatic_a:
      {
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_Field *field = pool_data[fieldref_index].field;
	PUSHA(*(jobject*) (field->u.addr));
      }
      NEXT_INSN;

     insn_putfield_1:
      SAVE_PC;
      {
	jint    value = POPI();
	jobject obj   = POPA();
	NULLCHECK(obj);
	jint field_offset = get2u (pc); pc += 2;
	*(jbyte*) ((char*)obj + field_offset) = value;
      }
      NEXT_INSN;

     insn_putfield_2:
      SAVE_PC;
      {
	jint    value = POPI();
	jobject obj   = POPA();
	NULLCHECK(obj);
	jint field_offset = get2u (pc); pc += 2;
	*(jchar*) ((char*)obj + field_offset) = value;
      }
      NEXT_INSN;

     insn_putfield_4:
      SAVE_PC;
      {
	jint    value = POPI();
	jobject obj   = POPA();
	NULLCHECK(obj);
	jint field_offset = get2u (pc); pc += 2;
	*(jint*) ((char*)obj + field_offset) = value;
      }
      NEXT_INSN;

     insn_putfield_8:
      SAVE_PC;
      {
	jlong   value = POPL();
	jobject obj   = POPA();
	NULLCHECK(obj);
	jint field_offset = get2u (pc); pc += 2;
	*(jlong*) ((char*)obj + field_offset) = value;
      }
      NEXT_INSN;

     insn_putfield_a:
      SAVE_PC;
      {
	jobject value = POPA();
	jobject obj   = POPA();
	NULLCHECK(obj);
	jint field_offset = get2u (pc); pc += 2;
	*(jobject*) ((char*)obj + field_offset) = value;
      }
      NEXT_INSN;

     insn_putstatic_1:
      {
	jint    value = POPI();
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_Field *field = pool_data[fieldref_index].field;
	*(jbyte*) (field->u.addr) = value;
      }
      NEXT_INSN;

     insn_putstatic_2:
      {
	jint    value = POPI();
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_Field *field = pool_data[fieldref_index].field;
	*(jchar*) (field->u.addr) = value;
      }
      NEXT_INSN;

     insn_putstatic_4:
      {
	jint    value = POPI();
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_Field *field = pool_data[fieldref_index].field;
	*(jint*) (field->u.addr) = value;
      }
      NEXT_INSN;

     insn_putstatic_8:
      {
	jlong    value = POPL();
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_Field *field = pool_data[fieldref_index].field;
	*(jlong*) (field->u.addr) = value;
      }
      NEXT_INSN;

     insn_putstatic_a:
      {
	jobject value = POPA();
	jint fieldref_index = get2u (pc); pc += 2;
	_Jv_Field *field = pool_data[fieldref_index].field;
	*(jobject*) (field->u.addr) = value;
      }
      NEXT_INSN;

     insn_invokespecial:
      SAVE_PC;
      {
	int index = get2u (pc); pc += 2;

	rmeth = (_Jv_ResolvePoolEntry (defining_class, index)).rmethod;

	sp -= rmeth->stack_item_count;

	NULLCHECK(sp[0]);

	fun = (void (*) (...))rmeth->method->ncode;
      }
      goto perform_invoke;

     insn_invokestatic:
      SAVE_PC;
      {
	int index = get2u (pc); pc += 2;

	rmeth = (_Jv_ResolvePoolEntry (defining_class, index)).rmethod;

	sp -= rmeth->stack_item_count;

	_Jv_InitClass (rmeth->klass);
	fun = (void (*) (...))rmeth->method->ncode;
      }
      goto perform_invoke;

     insn_invokeinterface:
      SAVE_PC;
      {
	int index = get2u (pc); pc += 2;

	// invokeinterface has two unused bytes...
	pc += 2;

	rmeth = (_Jv_ResolvePoolEntry (defining_class, index)).rmethod;

	sp -= rmeth->stack_item_count;
	NULLCHECK(sp[0]);

	jobject rcv = sp[0].o;

	fun = (void (*) (...))
	  _Jv_LookupInterfaceMethod (rcv->getClass (),
				     rmeth->method->name,
				     rmeth->method->signature);
      }
      goto perform_invoke;


     insn_new:
      SAVE_PC;
      {
	int index = get2u (pc); pc += 2;
	jclass klass = (_Jv_ResolvePoolEntry (defining_class, index)).clazz;
	_Jv_InitClass (klass);
	jobject res = _Jv_AllocObject (klass, klass->size_in_bytes);
	PUSHA (res);
      }
      NEXT_INSN;

     insn_newarray:
      SAVE_PC;
      {
	int atype = get1u (pc++);
	int size  = POPI();
	jobject result = _Jv_NewArray (atype, size);
	PUSHA (result);
      }
      NEXT_INSN;

     insn_anewarray:
      SAVE_PC;
      {
	int index = get2u (pc); pc += 2;
	jclass klass = (_Jv_ResolvePoolEntry (defining_class, index)).clazz;
	int size  = POPI();
	_Jv_InitClass (klass);
	jobject result = _Jv_NewObjectArray (size, klass, 0);
	PUSHA (result);
      }
      NEXT_INSN;

     insn_arraylength:
      SAVE_PC;
      {
	__JArray *arr = (__JArray*)POPA();
	PUSHI (arr->length);
      }
      NEXT_INSN;

     insn_athrow:
      SAVE_PC;
      {
	jobject value = POPA();
	JvThrow (value);
      }
      NEXT_INSN;

     insn_checkcast:
      SAVE_PC;
      {
	jobject value = POPA();
	jint index = get2u (pc); pc += 2;
	jclass to = (_Jv_ResolvePoolEntry (defining_class, index)).clazz;

	if (value != NULL && ! to->isInstance (value))
	  {
	    JvThrow (new java::lang::ClassCastException
		     (to->getName()));
	  }

	PUSHA (value);
      }
      NEXT_INSN;

     insn_instanceof:
      SAVE_PC;
      {
	jobject value = POPA();
	jint index = get2u (pc); pc += 2;
	jclass to = (_Jv_ResolvePoolEntry (defining_class, index)).clazz;
	PUSHI (to->isInstance (value));
      }
      NEXT_INSN;

     insn_monitorenter:
      SAVE_PC;
      {
	jobject value = POPA();
	NULLCHECK(value);
	_Jv_MonitorEnter (value);
      }
      NEXT_INSN;

     insn_monitorexit:
      SAVE_PC;
      {
	jobject value = POPA();
	NULLCHECK(value);
	_Jv_MonitorExit (value);
      }
      NEXT_INSN;

     insn_ifnull:
      {
	unsigned char* base_pc = pc-1;
	jint offset = get2s (pc); pc += 2;
	jobject val = POPA();
	if (val == NULL)
	  pc = base_pc+offset;
      }
      NEXT_INSN;

     insn_ifnonnull:
      {
	unsigned char* base_pc = pc-1;
	jint offset = get2s (pc); pc += 2;
	jobject val = POPA();
	if (val != NULL)
	  pc = base_pc+offset;
      }
      NEXT_INSN;

     insn_wide:
      SAVE_PC;
      {
	jint the_mod_op = get1u (pc++);
	jint wide       = get2u (pc); pc += 2;

	switch (the_mod_op)
	  {
	  case op_istore:
	    STOREI (wide);
	    NEXT_INSN;

	  case op_fstore:
	    STOREF (wide);
	    NEXT_INSN;

	  case op_astore:
	    STOREA (wide);
	    NEXT_INSN;

	  case op_lload:
	    LOADL (wide);
	    NEXT_INSN;

	  case op_dload:
	    LOADD (wide);
	    NEXT_INSN;

	  case op_iload:
	    LOADI (wide);
	    NEXT_INSN;

	  case op_aload:
	    LOADA (wide);
	    NEXT_INSN;

	  case op_lstore:
	    STOREL (wide);
	    NEXT_INSN;

	  case op_dstore:
	    STORED (wide);
	    NEXT_INSN;

	  case op_ret:
	    pc = (unsigned char*) PEEKA (wide);
	    NEXT_INSN;

	  case op_iinc:
	    {
	      jint amount = get2s (pc); pc += 2;
	      jint value = PEEKI (wide);
	      POKEI (wide, value+amount);
	    }
	    NEXT_INSN;

	  default:
	    throw_internal_error ("illegal bytecode modified by wide");
	  }

      }

     insn_multianewarray:
      SAVE_PC;
      {
	int kind_index = get2u (pc); pc += 2;
	int dim        = get1u (pc); pc += 1;

	jclass type    
	  = (_Jv_ResolvePoolEntry (defining_class, kind_index)).clazz;
	_Jv_InitClass (type);
	jint *sizes    = (jint*) alloca (sizeof (jint)*dim);

	for (int i = dim - 1; i >= 0; i--)
	  {
	    sizes[i] = POPI ();
	  }

	jobject res    = _Jv_NewMultiArray (type,dim, sizes);

	PUSHA (res);
      }
      NEXT_INSN;

     insn_goto_w:
      {
	unsigned char* base_pc = pc-1;
	int offset = get4 (pc); pc += 4;
	pc = base_pc+offset;
      }
      NEXT_INSN;

     insn_jsr_w:
      {
	unsigned char* base_pc = pc-1;
	int offset = get4 (pc); pc += 4;
	PUSHA((jobject)pc);
	pc = base_pc+offset;
      }
      NEXT_INSN;
}


static void
throw_internal_error (char *msg)
{
  JvThrow (new java::lang::InternalError (JvNewStringLatin1 (msg)));
}

static void 
throw_incompatible_class_change_error (jstring msg)
{
  JvThrow (new java::lang::IncompatibleClassChangeError (msg));
}

#if !HANDLE_SEGV
static java::lang::NullPointerException *null_pointer_exc;
static void 
throw_null_pointer_exception ()
{
  if (null_pointer_exc == NULL)
    null_pointer_exc = new java::lang::NullPointerException;

  JvThrow (null_pointer_exc);
}
#endif

#if !HANDLE_FPE
static java::lang::ArithmeticException *arithmetic_exc;
static void 
throw_arithmetic_exception ()
{
  if (arithmetic_exc == NULL)
    arithmetic_exc = new java::lang::ArithmeticException
      (JvNewStringLatin1 ("/ by zero"));

  JvThrow (arithmetic_exc);
}
#endif


#endif // INTERPRETER