aboutsummaryrefslogtreecommitdiffstats
path: root/code/qcommon/vm_x86.c
blob: 3dccd3f75ac43c628accdf41e370b89f9b3ef858 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.

This file is part of Quake III Arena source code.

Quake III Arena source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.

Quake III Arena source code is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Quake III Arena source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
// vm_x86.c -- load time compiler and execution environment for x86

#include "vm_local.h"
#ifdef _WIN32
#include <windows.h>
#endif

#ifdef __FreeBSD__
#include <sys/types.h>
#endif

#ifndef _WIN32
#include <sys/mman.h> // for PROT_ stuff
#endif

/* need this on NX enabled systems (i386 with PAE kernel or
 * noexec32=on x86_64) */
#ifdef __linux__
#define VM_X86_MMAP
#endif

static void VM_Destroy_Compiled(vm_t* self);

/*

  eax	scratch
  ebx	scratch
  ecx	scratch (required for shifts)
  edx	scratch (required for divisions)
  esi	program stack
  edi	opstack

*/

static	byte	*buf = NULL;
static	byte	*jused = NULL;
static	int		compiledOfs = 0;
static	byte	*code = NULL;
static	int		pc = 0;

static	int		*instructionPointers = NULL;

#define FTOL_PTR

#ifdef _MSC_VER

#if defined( FTOL_PTR )
int _ftol( float );
static	int		ftolPtr = (int)_ftol;
#endif

#else // _MSC_VER

#if defined( FTOL_PTR )

int qftol( void );
int qftol027F( void );
int qftol037F( void );
int qftol0E7F( void );
int qftol0F7F( void );


static	int		ftolPtr = (int)qftol0F7F;
#endif // FTOL_PTR

#endif

void AsmCall(void);
static void (*const asmCallPtr)(void) = AsmCall;


static	int		callMask = 0;

static	int	instruction, pass;
static	int	lastConst = 0;
static	int	oc0, oc1, pop0, pop1;

typedef enum 
{
	LAST_COMMAND_NONE	= 0,
	LAST_COMMAND_MOV_EDI_EAX,
	LAST_COMMAND_SUB_DI_4,
	LAST_COMMAND_SUB_DI_8,
} ELastCommand;

static	ELastCommand	LastCommand;

/*
=================
AsmCall
=================
*/
#ifdef _MSC_VER
__declspec( naked ) void AsmCall( void ) {
int		programStack;
int		*opStack;
int		syscallNum;
vm_t*	savedVM;

__asm {
	mov		eax, dword ptr [edi]
	sub		edi, 4
	test	eax,eax
	jl		systemCall
	// calling another vm function
	shl		eax,2
	add		eax, dword ptr [instructionPointers]
	call	dword ptr [eax]
	mov		eax, dword ptr [edi]
	and		eax, [callMask]
	ret
systemCall:

	// convert negative num to system call number
	// and store right before the first arg
	not		eax

	push    ebp
	mov     ebp, esp
	sub     esp, __LOCAL_SIZE

	mov		dword ptr syscallNum, eax	// so C code can get at it
	mov		dword ptr programStack, esi	// so C code can get at it
	mov		dword ptr opStack, edi

	push	ecx
	push	esi							// we may call recursively, so the
	push	edi							// statics aren't guaranteed to be around
}

	savedVM = currentVM;

	// save the stack to allow recursive VM entry
	currentVM->programStack = programStack - 4;
	*(int *)((byte *)currentVM->dataBase + programStack + 4) = syscallNum;
//VM_LogSyscalls(  (int *)((byte *)currentVM->dataBase + programStack + 4) );
	*(opStack+1) = currentVM->systemCall( (int *)((byte *)currentVM->dataBase + programStack + 4) );

	currentVM = savedVM;

_asm {
	pop		edi
	pop		esi
	pop		ecx
	add		edi, 4		// we added the return value

	mov     esp, ebp
	pop     ebp

	ret
}

}

#else //!_MSC_VER

#if defined(__MINGW32__) || defined(MACOS_X) // _ is prepended to compiled symbols
#define CMANGVAR(sym) "_"#sym
#define CMANGFUNC(sym) "_"#sym
#elif defined(__ICC) && (__ICC >= 1000)
#define CMANGVAR(sym) #sym".0"
#define CMANGFUNC(sym) #sym
#else
#define CMANGVAR(sym) #sym
#define CMANGFUNC(sym) #sym
#endif

static void __attribute__((cdecl, used)) CallAsmCall(int const syscallNum,
		int const programStack, int* const opStack)
{
	vm_t     *const vm   = currentVM;
	intptr_t *const data = (intptr_t*)(vm->dataBase + programStack + 4);

	// save the stack to allow recursive VM entry
	vm->programStack = programStack - 4;
	*data = syscallNum;
	opStack[1] = vm->systemCall(data);

	currentVM = vm;
}

__asm__(
	".text\n\t"
	".p2align 4,,15\n\t"
#if defined __ELF__
	".type " CMANGFUNC(AsmCall) ", @function\n"
#endif
	CMANGFUNC(AsmCall) ":\n\t"
	"movl  (%edi), %eax\n\t"
	"subl  $4, %edi\n\t"
	"testl %eax, %eax\n\t"
	"jl    0f\n\t"
	"shll  $2, %eax\n\t"
	"addl  " CMANGVAR(instructionPointers) ", %eax\n\t"
	"call  *(%eax)\n\t"
	"movl  (%edi), %eax\n\t"
	"andl  " CMANGVAR(callMask) ", %eax\n\t"
	"ret\n"
	"0:\n\t" // system call
	"notl  %eax\n\t"
	"pushl %ebp\n\t"
	"movl  %esp, %ebp\n\t"
	"andl $-16, %esp\n\t" // align the stack so engine can use sse
	"pushl %ecx\n\t"
	"pushl %edi\n\t" // opStack
	"pushl %esi\n\t" // programStack
	"pushl %eax\n\t" // syscallNum
	"call  " CMANGFUNC(CallAsmCall) "\n\t"
	"addl  $12, %esp\n\t"
	"popl  %ecx\n\t"
	"movl  %ebp, %esp\n\t"
	"popl  %ebp\n\t"
	"addl  $4, %edi\n\t"
	"ret\n\t"
#if defined __ELF__
	".size " CMANGFUNC(AsmCall)", .-" CMANGFUNC(AsmCall)
#endif
);

#endif

static int	Constant4( void ) {
	int		v;

	v = code[pc] | (code[pc+1]<<8) | (code[pc+2]<<16) | (code[pc+3]<<24);
	pc += 4;
	return v;
}

static int	Constant1( void ) {
	int		v;

	v = code[pc];
	pc += 1;
	return v;
}

static void Emit1( int v ) 
{
	buf[ compiledOfs ] = v;
	compiledOfs++;

	LastCommand = LAST_COMMAND_NONE;
}

#if 0
static void Emit2( int v ) {
	Emit1( v & 255 );
	Emit1( ( v >> 8 ) & 255 );
}
#endif

static void Emit4( int v ) {
	Emit1( v & 255 );
	Emit1( ( v >> 8 ) & 255 );
	Emit1( ( v >> 16 ) & 255 );
	Emit1( ( v >> 24 ) & 255 );
}

static int Hex( int c ) {
	if ( c >= 'a' && c <= 'f' ) {
		return 10 + c - 'a';
	}
	if ( c >= 'A' && c <= 'F' ) {
		return 10 + c - 'A';
	}
	if ( c >= '0' && c <= '9' ) {
		return c - '0';
	}

	Com_Error( ERR_DROP, "Hex: bad char '%c'", c );

	return 0;
}
static void EmitString( const char *string ) {
	int		c1, c2;
	int		v;

	while ( 1 ) {
		c1 = string[0];
		c2 = string[1];

		v = ( Hex( c1 ) << 4 ) | Hex( c2 );
		Emit1( v );

		if ( !string[2] ) {
			break;
		}
		string += 3;
	}
}



static void EmitCommand(ELastCommand command)
{
	switch(command)
	{
		case LAST_COMMAND_MOV_EDI_EAX:
			EmitString( "89 07" );		// mov dword ptr [edi], eax
			break;

		case LAST_COMMAND_SUB_DI_4:
			EmitString( "83 EF 04" );	// sub edi, 4
			break;

		case LAST_COMMAND_SUB_DI_8:
			EmitString( "83 EF 08" );	// sub edi, 8
			break;
		default:
			break;
	}
	LastCommand = command;
}

static void EmitAddEDI4(vm_t *vm) {
	if (LastCommand == LAST_COMMAND_SUB_DI_4 && jused[instruction-1] == 0) 
	{		// sub di,4
		compiledOfs -= 3;
		vm->instructionPointers[ instruction-1 ] = compiledOfs;
		return;
	}
	if (LastCommand == LAST_COMMAND_SUB_DI_8 && jused[instruction-1] == 0) 
	{		// sub di,8
		compiledOfs -= 3;
		vm->instructionPointers[ instruction-1 ] = compiledOfs;
		EmitString( "83 EF 04" );	//	sub edi,4
		return;
	}
	EmitString( "83 C7 04" );	//	add edi,4
}

static void EmitMovEAXEDI(vm_t *vm) {
	if (LastCommand == LAST_COMMAND_MOV_EDI_EAX) 
	{	// mov [edi], eax
		compiledOfs -= 2;
		vm->instructionPointers[ instruction-1 ] = compiledOfs;
		return;
	}
	if (pop1 == OP_DIVI || pop1 == OP_DIVU || pop1 == OP_MULI || pop1 == OP_MULU ||
		pop1 == OP_STORE4 || pop1 == OP_STORE2 || pop1 == OP_STORE1 ) 
	{	
		return;
	}
	if (pop1 == OP_CONST && buf[compiledOfs-6] == 0xC7 && buf[compiledOfs-5] == 0x07 ) 
	{	// mov edi, 0x123456
		compiledOfs -= 6;
		vm->instructionPointers[ instruction-1 ] = compiledOfs;
		EmitString( "B8" );			// mov	eax, 0x12345678
		Emit4( lastConst );
		return;
	}
	EmitString( "8B 07" );		// mov eax, dword ptr [edi]
}

qboolean EmitMovEBXEDI(vm_t *vm, int andit) {
	if (LastCommand == LAST_COMMAND_MOV_EDI_EAX) 
	{	// mov [edi], eax
		compiledOfs -= 2;
		vm->instructionPointers[ instruction-1 ] = compiledOfs;
		EmitString( "8B D8");		// mov bx, eax
		return qfalse;
	}
	if (pop1 == OP_DIVI || pop1 == OP_DIVU || pop1 == OP_MULI || pop1 == OP_MULU ||
		pop1 == OP_STORE4 || pop1 == OP_STORE2 || pop1 == OP_STORE1 ) 
	{	
		EmitString( "8B D8");		// mov bx, eax
		return qfalse;
	}
	if (pop1 == OP_CONST && buf[compiledOfs-6] == 0xC7 && buf[compiledOfs-5] == 0x07 ) 
	{		// mov edi, 0x123456
		compiledOfs -= 6;
		vm->instructionPointers[ instruction-1 ] = compiledOfs;
		EmitString( "BB" );			// mov	ebx, 0x12345678
		if (andit) {
			Emit4( lastConst & andit );
		} else {
			Emit4( lastConst );
		}
		return qtrue;
	}

	EmitString( "8B 1F" );		// mov ebx, dword ptr [edi]
	return qfalse;
}

/*
=================
VM_Compile
=================
*/
void VM_Compile( vm_t *vm, vmHeader_t *header ) {
	int		op;
	int		maxLength;
	int		v;
	int		i;
	qboolean opt;

	// allocate a very large temp buffer, we will shrink it later
	maxLength = header->codeLength * 8;
	buf = Z_Malloc( maxLength );
	jused = Z_Malloc(header->instructionCount + 2 );
	
	Com_Memset(jused, 0, header->instructionCount+2);

	// ensure that the optimisation pass knows about all the jump
	// table targets
	for( i = 0; i < vm->numJumpTableTargets; i++ ) {
		jused[ *(int *)(vm->jumpTableTargets + ( i * sizeof( int ) ) ) ] = 1;
	}

	for(pass=0;pass<2;pass++) {
	oc0 = -23423;
	oc1 = -234354;
	pop0 = -43435;
	pop1 = -545455;

	// translate all instructions
	pc = 0;
	instruction = 0;
	code = (byte *)header + header->codeOffset;
	compiledOfs = 0;

	LastCommand = LAST_COMMAND_NONE;

	while ( instruction < header->instructionCount ) {
		if ( compiledOfs > maxLength - 16 ) {
			Com_Error( ERR_FATAL, "VM_CompileX86: maxLength exceeded" );
		}

		vm->instructionPointers[ instruction ] = compiledOfs;
		instruction++;

		if ( pc > header->codeLength ) {
			Com_Error( ERR_FATAL, "VM_CompileX86: pc > header->codeLength" );
		}

		op = code[ pc ];
		pc++;
		switch ( op ) {
		case 0:
			break;
		case OP_BREAK:
			EmitString( "CC" );			// int 3
			break;
		case OP_ENTER:
			EmitString( "81 EE" );		// sub	esi, 0x12345678
			Emit4( Constant4() );
			break;
		case OP_CONST:
			if (code[pc+4] == OP_LOAD4) {
				EmitAddEDI4(vm);
				EmitString( "BB" );		// mov	ebx, 0x12345678
				Emit4( (Constant4()&vm->dataMask) + (int)vm->dataBase);
				EmitString( "8B 03" );		// mov	eax, dword ptr [ebx]
				EmitCommand(LAST_COMMAND_MOV_EDI_EAX);		// mov dword ptr [edi], eax
				pc++;						// OP_LOAD4
				instruction += 1;
				break;
			}
			if (code[pc+4] == OP_LOAD2) {
				EmitAddEDI4(vm);
				EmitString( "BB" );		// mov	ebx, 0x12345678
				Emit4( (Constant4()&vm->dataMask) + (int)vm->dataBase);
				EmitString( "0F B7 03" );	// movzx	eax, word ptr [ebx]
				EmitCommand(LAST_COMMAND_MOV_EDI_EAX);		// mov dword ptr [edi], eax
				pc++;						// OP_LOAD4
				instruction += 1;
				break;
			}
			if (code[pc+4] == OP_LOAD1) {
				EmitAddEDI4(vm);
				EmitString( "BB" );		// mov	ebx, 0x12345678
				Emit4( (Constant4()&vm->dataMask) + (int)vm->dataBase);
				EmitString( "0F B6 03" );	// movzx	eax, byte ptr [ebx]
				EmitCommand(LAST_COMMAND_MOV_EDI_EAX);		// mov dword ptr [edi], eax
				pc++;						// OP_LOAD4
				instruction += 1;
				break;
			}
			if (code[pc+4] == OP_STORE4) {
				opt = EmitMovEBXEDI(vm, (vm->dataMask & ~3));
				EmitString( "B8" );			// mov	eax, 0x12345678
				Emit4( Constant4() );
//				if (!opt) {
//					EmitString( "81 E3" );		// and ebx, 0x12345678
//					Emit4( vm->dataMask & ~3 );
//				}
				EmitString( "89 83" );		// mov dword ptr [ebx+0x12345678], eax
				Emit4( (int)vm->dataBase );
				EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
				pc++;						// OP_STORE4
				instruction += 1;
				break;
			}
			if (code[pc+4] == OP_STORE2) {
				opt = EmitMovEBXEDI(vm, (vm->dataMask & ~1));
				EmitString( "B8" );			// mov	eax, 0x12345678
				Emit4( Constant4() );
//				if (!opt) {
//					EmitString( "81 E3" );		// and ebx, 0x12345678
//					Emit4( vm->dataMask & ~1 );
//				}
				EmitString( "66 89 83" );	// mov word ptr [ebx+0x12345678], eax
				Emit4( (int)vm->dataBase );
				EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
				pc++;						// OP_STORE4
				instruction += 1;
				break;
			}
			if (code[pc+4] == OP_STORE1) {
				opt = EmitMovEBXEDI(vm, vm->dataMask);
				EmitString( "B8" );			// mov	eax, 0x12345678
				Emit4( Constant4() );
//				if (!opt) {
//					EmitString( "81 E3" );	// and ebx, 0x12345678
//					Emit4( vm->dataMask );
//				}
				EmitString( "88 83" );		// mov byte ptr [ebx+0x12345678], eax
				Emit4( (int)vm->dataBase );
				EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
				pc++;						// OP_STORE4
				instruction += 1;
				break;
			}
			if (code[pc+4] == OP_ADD) {
				EmitString( "81 07" );		// add dword ptr [edi], 0x1234567
				Emit4( Constant4() );
				pc++;						// OP_ADD
				instruction += 1;
				break;
			}
			if (code[pc+4] == OP_SUB) {
				EmitString( "81 2F" );		// sub dword ptr [edi], 0x1234567
				Emit4( Constant4() );
				pc++;						// OP_ADD
				instruction += 1;
				break;
			}
			EmitAddEDI4(vm);
			EmitString( "C7 07" );		// mov	dword ptr [edi], 0x12345678
			lastConst = Constant4();
			Emit4( lastConst );
			if (code[pc] == OP_JUMP) {
				jused[lastConst] = 1;
			}
			break;
		case OP_LOCAL:
			EmitAddEDI4(vm);
			EmitString( "8D 86" );		// lea eax, [0x12345678 + esi]
			oc0 = oc1;
			oc1 = Constant4();
			Emit4( oc1 );
			EmitCommand(LAST_COMMAND_MOV_EDI_EAX);		// mov dword ptr [edi], eax
			break;
		case OP_ARG:
			EmitMovEAXEDI(vm);			// mov	eax,dword ptr [edi]
			EmitString( "89 86" );		// mov	dword ptr [esi+database],eax
			// FIXME: range check
			Emit4( Constant1() + (int)vm->dataBase );
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_CALL:
			EmitString( "C7 86" );		// mov dword ptr [esi+database],0x12345678
			Emit4( (int)vm->dataBase );
			Emit4( pc );
			EmitString( "FF 15" );		// call asmCallPtr
			Emit4( (int)&asmCallPtr );
			break;
		case OP_PUSH:
			EmitAddEDI4(vm);
			break;
		case OP_POP:
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_LEAVE:
			v = Constant4();
			EmitString( "81 C6" );		// add	esi, 0x12345678
			Emit4( v );
			EmitString( "C3" );			// ret
			break;
		case OP_LOAD4:
			if (code[pc] == OP_CONST && code[pc+5] == OP_ADD && code[pc+6] == OP_STORE4) {
				if (oc0 == oc1 && pop0 == OP_LOCAL && pop1 == OP_LOCAL) {
					compiledOfs -= 11;
					vm->instructionPointers[ instruction-1 ] = compiledOfs;
				}
				pc++;						// OP_CONST
				v = Constant4();
				EmitMovEBXEDI(vm, vm->dataMask);
				if (v == 1 && oc0 == oc1 && pop0 == OP_LOCAL && pop1 == OP_LOCAL) {
					EmitString( "FF 83");		// inc dword ptr [ebx + 0x12345678]
					Emit4( (int)vm->dataBase );
				} else {
					EmitString( "8B 83" );		// mov	eax, dword ptr [ebx + 0x12345678]
					Emit4( (int)vm->dataBase );
					EmitString( "05"  );		// add eax, const
					Emit4( v );
					if (oc0 == oc1 && pop0 == OP_LOCAL && pop1 == OP_LOCAL) {
						EmitString( "89 83" );		// mov dword ptr [ebx+0x12345678], eax
						Emit4( (int)vm->dataBase );
					} else {
						EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
						EmitString( "8B 1F" );		// mov	ebx, dword ptr [edi]
						EmitString( "89 83" );		// mov dword ptr [ebx+0x12345678], eax
						Emit4( (int)vm->dataBase );
					}
				}
				EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
				pc++;						// OP_ADD
				pc++;						// OP_STORE
				instruction += 3;
				break;
			}

			if (code[pc] == OP_CONST && code[pc+5] == OP_SUB && code[pc+6] == OP_STORE4) {
				if (oc0 == oc1 && pop0 == OP_LOCAL && pop1 == OP_LOCAL) {
					compiledOfs -= 11;
					vm->instructionPointers[ instruction-1 ] = compiledOfs;
				}
				EmitMovEBXEDI(vm, vm->dataMask);
				EmitString( "8B 83" );		// mov	eax, dword ptr [ebx + 0x12345678]
				Emit4( (int)vm->dataBase );
				pc++;						// OP_CONST
				v = Constant4();
				if (v == 1 && oc0 == oc1 && pop0 == OP_LOCAL && pop1 == OP_LOCAL) {
					EmitString( "FF 8B");		// dec dword ptr [ebx + 0x12345678]
					Emit4( (int)vm->dataBase );
				} else {
					EmitString( "2D"  );		// sub eax, const
					Emit4( v );
					if (oc0 == oc1 && pop0 == OP_LOCAL && pop1 == OP_LOCAL) {
						EmitString( "89 83" );		// mov dword ptr [ebx+0x12345678], eax
						Emit4( (int)vm->dataBase );
					} else {
						EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
						EmitString( "8B 1F" );		// mov	ebx, dword ptr [edi]
						EmitString( "89 83" );		// mov dword ptr [ebx+0x12345678], eax
						Emit4( (int)vm->dataBase );
					}
				}
				EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
				pc++;						// OP_SUB
				pc++;						// OP_STORE
				instruction += 3;
				break;
			}

			if (buf[compiledOfs-2] == 0x89 && buf[compiledOfs-1] == 0x07) {
				compiledOfs -= 2;
				vm->instructionPointers[ instruction-1 ] = compiledOfs;
				EmitString( "8B 80");	// mov eax, dword ptr [eax + 0x1234567]
				Emit4( (int)vm->dataBase );
				EmitCommand(LAST_COMMAND_MOV_EDI_EAX);		// mov dword ptr [edi], eax
				break;
			}
			EmitMovEBXEDI(vm, vm->dataMask);
			EmitString( "8B 83" );		// mov	eax, dword ptr [ebx + 0x12345678]
			Emit4( (int)vm->dataBase );
			EmitCommand(LAST_COMMAND_MOV_EDI_EAX);		// mov dword ptr [edi], eax
			break;
		case OP_LOAD2:
			EmitMovEBXEDI(vm, vm->dataMask);
			EmitString( "0F B7 83" );	// movzx	eax, word ptr [ebx + 0x12345678]
			Emit4( (int)vm->dataBase );
			EmitCommand(LAST_COMMAND_MOV_EDI_EAX);		// mov dword ptr [edi], eax
			break;
		case OP_LOAD1:
			EmitMovEBXEDI(vm, vm->dataMask);
			EmitString( "0F B6 83" );	// movzx eax, byte ptr [ebx + 0x12345678]
			Emit4( (int)vm->dataBase );
			EmitCommand(LAST_COMMAND_MOV_EDI_EAX);		// mov dword ptr [edi], eax
			break;
		case OP_STORE4:
			EmitMovEAXEDI(vm);	
			EmitString( "8B 5F FC" );	// mov	ebx, dword ptr [edi-4]
//			if (pop1 != OP_CALL) {
//				EmitString( "81 E3" );		// and ebx, 0x12345678
//				Emit4( vm->dataMask & ~3 );
//			}
			EmitString( "89 83" );		// mov dword ptr [ebx+0x12345678], eax
			Emit4( (int)vm->dataBase );
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			break;
		case OP_STORE2:
			EmitMovEAXEDI(vm);	
			EmitString( "8B 5F FC" );	// mov	ebx, dword ptr [edi-4]
//			EmitString( "81 E3" );		// and ebx, 0x12345678
//			Emit4( vm->dataMask & ~1 );
			EmitString( "66 89 83" );	// mov word ptr [ebx+0x12345678], eax
			Emit4( (int)vm->dataBase );
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			break;
		case OP_STORE1:
			EmitMovEAXEDI(vm);	
			EmitString( "8B 5F FC" );	// mov	ebx, dword ptr [edi-4]
//			EmitString( "81 E3" );		// and ebx, 0x12345678
//			Emit4( vm->dataMask );
			EmitString( "88 83" );		// mov byte ptr [ebx+0x12345678], eax
			Emit4( (int)vm->dataBase );
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			break;

		case OP_EQ:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "8B 47 04" );	// mov	eax, dword ptr [edi+4]
			EmitString( "3B 47 08" );	// cmp	eax, dword ptr [edi+8]
			EmitString( "75 06" );		// jne +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;
		case OP_NE:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "8B 47 04" );	// mov	eax, dword ptr [edi+4]
			EmitString( "3B 47 08" );	// cmp	eax, dword ptr [edi+8]
			EmitString( "74 06" );		// je +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;
		case OP_LTI:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "8B 47 04" );	// mov	eax, dword ptr [edi+4]
			EmitString( "3B 47 08" );	// cmp	eax, dword ptr [edi+8]
			EmitString( "7D 06" );		// jnl +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;
		case OP_LEI:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "8B 47 04" );	// mov	eax, dword ptr [edi+4]
			EmitString( "3B 47 08" );	// cmp	eax, dword ptr [edi+8]
			EmitString( "7F 06" );		// jnle +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;
		case OP_GTI:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "8B 47 04" );	// mov	eax, dword ptr [edi+4]
			EmitString( "3B 47 08" );	// cmp	eax, dword ptr [edi+8]
			EmitString( "7E 06" );		// jng +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;
		case OP_GEI:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "8B 47 04" );	// mov	eax, dword ptr [edi+4]
			EmitString( "3B 47 08" );	// cmp	eax, dword ptr [edi+8]
			EmitString( "7C 06" );		// jnge +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;
		case OP_LTU:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "8B 47 04" );	// mov	eax, dword ptr [edi+4]
			EmitString( "3B 47 08" );	// cmp	eax, dword ptr [edi+8]
			EmitString( "73 06" );		// jnb +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;
		case OP_LEU:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "8B 47 04" );	// mov	eax, dword ptr [edi+4]
			EmitString( "3B 47 08" );	// cmp	eax, dword ptr [edi+8]
			EmitString( "77 06" );		// jnbe +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;
		case OP_GTU:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "8B 47 04" );	// mov	eax, dword ptr [edi+4]
			EmitString( "3B 47 08" );	// cmp	eax, dword ptr [edi+8]
			EmitString( "76 06" );		// jna +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;
		case OP_GEU:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "8B 47 04" );	// mov	eax, dword ptr [edi+4]
			EmitString( "3B 47 08" );	// cmp	eax, dword ptr [edi+8]
			EmitString( "72 06" );		// jnae +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;
		case OP_EQF:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "D9 47 04" );	// fld dword ptr [edi+4]
			EmitString( "D8 5F 08" );	// fcomp dword ptr [edi+8]
			EmitString( "DF E0" );		// fnstsw ax
			EmitString( "F6 C4 40" );	// test	ah,0x40
			EmitString( "74 06" );		// je +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;			
		case OP_NEF:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "D9 47 04" );	// fld dword ptr [edi+4]
			EmitString( "D8 5F 08" );	// fcomp dword ptr [edi+8]
			EmitString( "DF E0" );		// fnstsw ax
			EmitString( "F6 C4 40" );	// test	ah,0x40
			EmitString( "75 06" );		// jne +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;			
		case OP_LTF:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "D9 47 04" );	// fld dword ptr [edi+4]
			EmitString( "D8 5F 08" );	// fcomp dword ptr [edi+8]
			EmitString( "DF E0" );		// fnstsw ax
			EmitString( "F6 C4 01" );	// test	ah,0x01
			EmitString( "74 06" );		// je +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;			
		case OP_LEF:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "D9 47 04" );	// fld dword ptr [edi+4]
			EmitString( "D8 5F 08" );	// fcomp dword ptr [edi+8]
			EmitString( "DF E0" );		// fnstsw ax
			EmitString( "F6 C4 41" );	// test	ah,0x41
			EmitString( "74 06" );		// je +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;			
		case OP_GTF:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "D9 47 04" );	// fld dword ptr [edi+4]
			EmitString( "D8 5F 08" );	// fcomp dword ptr [edi+8]
			EmitString( "DF E0" );		// fnstsw ax
			EmitString( "F6 C4 41" );	// test	ah,0x41
			EmitString( "75 06" );		// jne +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;			
		case OP_GEF:
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			EmitString( "D9 47 04" );	// fld dword ptr [edi+4]
			EmitString( "D8 5F 08" );	// fcomp dword ptr [edi+8]
			EmitString( "DF E0" );		// fnstsw ax
			EmitString( "F6 C4 01" );	// test	ah,0x01
			EmitString( "75 06" );		// jne +6
			EmitString( "FF 25" );		// jmp	[0x12345678]
			v = Constant4();
			jused[v] = 1;
			Emit4( (int)vm->instructionPointers + v*4 );
			break;			
		case OP_NEGI:
			EmitString( "F7 1F" );		// neg dword ptr [edi]
			break;
		case OP_ADD:
			EmitMovEAXEDI(vm);			// mov eax, dword ptr [edi]
			EmitString( "01 47 FC" );	// add dword ptr [edi-4],eax
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_SUB:
			EmitMovEAXEDI(vm);			// mov eax, dword ptr [edi]
			EmitString( "29 47 FC" );	// sub dword ptr [edi-4],eax
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_DIVI:
			EmitString( "8B 47 FC" );	// mov eax,dword ptr [edi-4]
			EmitString( "99" );			// cdq
			EmitString( "F7 3F" );		// idiv dword ptr [edi]
			EmitString( "89 47 FC" );	// mov dword ptr [edi-4],eax
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_DIVU:
			EmitString( "8B 47 FC" );	// mov eax,dword ptr [edi-4]
			EmitString( "33 D2" );		// xor edx, edx
			EmitString( "F7 37" );		// div dword ptr [edi]
			EmitString( "89 47 FC" );	// mov dword ptr [edi-4],eax
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_MODI:
			EmitString( "8B 47 FC" );	// mov eax,dword ptr [edi-4]
			EmitString( "99" );			// cdq
			EmitString( "F7 3F" );		// idiv dword ptr [edi]
			EmitString( "89 57 FC" );	// mov dword ptr [edi-4],edx
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_MODU:
			EmitString( "8B 47 FC" );	// mov eax,dword ptr [edi-4]
			EmitString( "33 D2" );		// xor edx, edx
			EmitString( "F7 37" );		// div dword ptr [edi]
			EmitString( "89 57 FC" );	// mov dword ptr [edi-4],edx
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_MULI:
			EmitString( "8B 47 FC" );	// mov eax,dword ptr [edi-4]
			EmitString( "F7 2F" );		// imul dword ptr [edi]
			EmitString( "89 47 FC" );	// mov dword ptr [edi-4],eax
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_MULU:
			EmitString( "8B 47 FC" );	// mov eax,dword ptr [edi-4]
			EmitString( "F7 27" );		// mul dword ptr [edi]
			EmitString( "89 47 FC" );	// mov dword ptr [edi-4],eax
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_BAND:
			EmitMovEAXEDI(vm);			// mov eax, dword ptr [edi]
			EmitString( "21 47 FC" );	// and dword ptr [edi-4],eax
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_BOR:
			EmitMovEAXEDI(vm);			// mov eax, dword ptr [edi]
			EmitString( "09 47 FC" );	// or dword ptr [edi-4],eax
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_BXOR:
			EmitMovEAXEDI(vm);			// mov eax, dword ptr [edi]
			EmitString( "31 47 FC" );	// xor dword ptr [edi-4],eax
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_BCOM:
			EmitString( "F7 17" );		// not dword ptr [edi]
			break;
		case OP_LSH:
			EmitString( "8B 0F" );		// mov ecx, dword ptr [edi]
			EmitString( "D3 67 FC" );	// shl dword ptr [edi-4], cl
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_RSHI:
			EmitString( "8B 0F" );		// mov ecx, dword ptr [edi]
			EmitString( "D3 7F FC" );	// sar dword ptr [edi-4], cl
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_RSHU:
			EmitString( "8B 0F" );		// mov ecx, dword ptr [edi]
			EmitString( "D3 6F FC" );	// shr dword ptr [edi-4], cl
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_NEGF:
			EmitString( "D9 07" );		// fld dword ptr [edi]
			EmitString( "D9 E0" );		// fchs
			EmitString( "D9 1F" );		// fstp dword ptr [edi]
			break;
		case OP_ADDF:
			EmitString( "D9 47 FC" );	// fld dword ptr [edi-4]
			EmitString( "D8 07" );		// fadd dword ptr [edi]
			EmitString( "D9 5F FC" );	// fstp dword ptr [edi-4]
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			break;
		case OP_SUBF:
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			EmitString( "D9 07" );		// fld dword ptr [edi]
			EmitString( "D8 67 04" );	// fsub dword ptr [edi+4]
			EmitString( "D9 1F" );		// fstp dword ptr [edi]
			break;
		case OP_DIVF:
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			EmitString( "D9 07" );		// fld dword ptr [edi]
			EmitString( "D8 77 04" );	// fdiv dword ptr [edi+4]
			EmitString( "D9 1F" );		// fstp dword ptr [edi]
			break;
		case OP_MULF:
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			EmitString( "D9 07" );		// fld dword ptr [edi]
			EmitString( "D8 4f 04" );	// fmul dword ptr [edi+4]
			EmitString( "D9 1F" );		// fstp dword ptr [edi]
			break;
		case OP_CVIF:
			EmitString( "DB 07" );		// fild dword ptr [edi]
			EmitString( "D9 1F" );		// fstp dword ptr [edi]
			break;
		case OP_CVFI:
#ifndef FTOL_PTR // WHENHELLISFROZENOVER
			// not IEEE complient, but simple and fast
			EmitString( "D9 07" );		// fld dword ptr [edi]
			EmitString( "DB 1F" );		// fistp dword ptr [edi]
#else // FTOL_PTR
			// call the library conversion function
			EmitString( "D9 07" );		// fld dword ptr [edi]
			EmitString( "FF 15" );		// call ftolPtr
			Emit4( (int)&ftolPtr );
			EmitCommand(LAST_COMMAND_MOV_EDI_EAX);		// mov dword ptr [edi], eax
#endif
			break;
		case OP_SEX8:
			EmitString( "0F BE 07" );	// movsx eax, byte ptr [edi]
			EmitCommand(LAST_COMMAND_MOV_EDI_EAX);		// mov dword ptr [edi], eax
			break;
		case OP_SEX16:
			EmitString( "0F BF 07" );	// movsx eax, word ptr [edi]
			EmitCommand(LAST_COMMAND_MOV_EDI_EAX);		// mov dword ptr [edi], eax
			break;

		case OP_BLOCK_COPY:
			// FIXME: range check
			EmitString( "56" );			// push esi
			EmitString( "57" );			// push edi
			EmitString( "8B 37" );		// mov esi,[edi] 
			EmitString( "8B 7F FC" );	// mov edi,[edi-4] 
			EmitString( "B9" );			// mov ecx,0x12345678
			Emit4( Constant4() >> 2 );
			EmitString( "B8" );			// mov eax, datamask
			Emit4( vm->dataMask );
			EmitString( "BB" );			// mov ebx, database
			Emit4( (int)vm->dataBase );
			EmitString( "23 F0" );		// and esi, eax
			EmitString( "03 F3" );		// add esi, ebx
			EmitString( "23 F8" );		// and edi, eax
			EmitString( "03 FB" );		// add edi, ebx
			EmitString( "F3 A5" );		// rep movsd
			EmitString( "5F" );			// pop edi
			EmitString( "5E" );			// pop esi
			EmitCommand(LAST_COMMAND_SUB_DI_8);		// sub edi, 8
			break;

		case OP_JUMP:
			EmitCommand(LAST_COMMAND_SUB_DI_4);		// sub edi, 4
			EmitString( "8B 47 04" );	// mov eax,dword ptr [edi+4]
			// FIXME: range check
			EmitString( "FF 24 85" );	// jmp dword ptr [instructionPointers + eax * 4]
			Emit4( (int)vm->instructionPointers );
			break;
		default:
			Com_Error( ERR_DROP, "VM_CompileX86: bad opcode %i at offset %i", op, pc );
		}
		pop0 = pop1;
		pop1 = op;
	}
	}

	// copy to an exact size buffer on the hunk
	vm->codeLength = compiledOfs;
#ifdef VM_X86_MMAP
	vm->codeBase = mmap(NULL, compiledOfs, PROT_WRITE, MAP_SHARED|MAP_ANONYMOUS, -1, 0);
	if(vm->codeBase == (void*)-1)
		Com_Error(ERR_DROP, "VM_CompileX86: can't mmap memory");
#elif _WIN32
	// allocate memory with EXECUTE permissions under windows.
	vm->codeBase = VirtualAlloc(NULL, compiledOfs, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
	if(!vm->codeBase)
		Com_Error(ERR_DROP, "VM_CompileX86: VirtualAlloc failed");
#else
	vm->codeBase = malloc(compiledOfs);
#endif

	Com_Memcpy( vm->codeBase, buf, compiledOfs );

#ifdef VM_X86_MMAP
	if(mprotect(vm->codeBase, compiledOfs, PROT_READ|PROT_EXEC))
		Com_Error(ERR_DROP, "VM_CompileX86: mprotect failed");
#elif _WIN32
	{
		DWORD oldProtect = 0;
		
		// remove write permissions.
		if(!VirtualProtect(vm->codeBase, compiledOfs, PAGE_EXECUTE_READ, &oldProtect))
			Com_Error(ERR_DROP, "VM_CompileX86: VirtualProtect failed");
	}
#endif

	Z_Free( buf );
	Z_Free( jused );
	Com_Printf( "VM file %s compiled to %i bytes of code\n", vm->name, compiledOfs );

	vm->destroy = VM_Destroy_Compiled;

	// offset all the instruction pointers for the new location
	for ( i = 0 ; i < header->instructionCount ; i++ ) {
		vm->instructionPointers[i] += (int)vm->codeBase;
	}
}

void VM_Destroy_Compiled(vm_t* self)
{
#ifdef VM_X86_MMAP
	munmap(self->codeBase, self->codeLength);
#elif _WIN32
	VirtualFree(self->codeBase, 0, MEM_RELEASE);
#else
	free(self->codeBase);
#endif
}

/*
==============
VM_CallCompiled

This function is called directly by the generated code
==============
*/
int	VM_CallCompiled( vm_t *vm, int *args ) {
	int		stack[1024];
	int		programCounter;
	int		programStack;
	int		stackOnEntry;
	byte	*image;
	void	*opStack;
	int		*oldInstructionPointers;

	oldInstructionPointers = instructionPointers;

	currentVM = vm;
	instructionPointers = vm->instructionPointers;

	// interpret the code
	vm->currentlyInterpreting = qtrue;

	callMask = vm->dataMask;

	// we might be called recursively, so this might not be the very top
	programStack = vm->programStack;
	stackOnEntry = programStack;

	// set up the stack frame 
	image = vm->dataBase;

	programCounter = 0;

	programStack -= 48;

	*(int *)&image[ programStack + 44] = args[9];
	*(int *)&image[ programStack + 40] = args[8];
	*(int *)&image[ programStack + 36] = args[7];
	*(int *)&image[ programStack + 32] = args[6];
	*(int *)&image[ programStack + 28] = args[5];
	*(int *)&image[ programStack + 24] = args[4];
	*(int *)&image[ programStack + 20] = args[3];
	*(int *)&image[ programStack + 16] = args[2];
	*(int *)&image[ programStack + 12] = args[1];
	*(int *)&image[ programStack + 8 ] = args[0];
	*(int *)&image[ programStack + 4 ] = 0;	// return stack
	*(int *)&image[ programStack ] = -1;	// will terminate the loop on return

	// off we go into generated code...
	opStack = &stack;

	{
#ifdef _MSC_VER
		void *entryPoint = vm->codeBase;

		__asm {
			pushad
			mov    esi, programStack
			mov    edi, opStack
			call   entryPoint
			mov    programStack, esi
			mov    opStack, edi
			popad
		}
#else
		/* These registers are used as scratch registers and are destroyed after the
		 * call.  Do not use clobber, so they can be used as input for the asm. */
		unsigned eax;
		unsigned ebx;
		unsigned ecx;
		unsigned edx;

		__asm__ volatile(
			"call *%6"
			: "+S" (programStack), "+D" (opStack),
			  "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
			: "mr" (vm->codeBase)
			: "cc", "memory"
		);
#endif
	}

	if ( opStack != &stack[1] ) {
		Com_Error( ERR_DROP, "opStack corrupted in compiled code" );
	}
	if ( programStack != stackOnEntry - 48 ) {
		Com_Error( ERR_DROP, "programStack corrupted in compiled code" );
	}

	vm->programStack = stackOnEntry;

	// in case we were recursively called by another vm
	instructionPointers = oldInstructionPointers;

	return *(int *)opStack;
}