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lilium-voyager/code/qcommon/vm.c

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/*
===========================================================================
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.c -- virtual machine
/*
intermix code and data
symbol table
a dll has one imported function: VM_SystemCall
and one exported function: Perform
*/
#include "vm_local.h"
vm_t *currentVM = NULL;
vm_t *lastVM = NULL;
int vm_debugLevel;
// used by Com_Error to get rid of running vm's before longjmp
static int forced_unload;
#define MAX_VM 3
vm_t vmTable[MAX_VM];
void VM_VmInfo_f( void );
void VM_VmProfile_f( void );
#if 0 // 64bit!
// converts a VM pointer to a C pointer and
// checks to make sure that the range is acceptable
void *VM_VM2C( vmptr_t p, int length ) {
return (void *)p;
}
#endif
void VM_Debug( int level ) {
vm_debugLevel = level;
}
/*
==============
VM_Init
==============
*/
void VM_Init( void ) {
Cvar_Get( "vm_cgame", "2", CVAR_ARCHIVE ); // !@# SHIP WITH SET TO 2
Cvar_Get( "vm_game", "2", CVAR_ARCHIVE ); // !@# SHIP WITH SET TO 2
Cvar_Get( "vm_ui", "2", CVAR_ARCHIVE ); // !@# SHIP WITH SET TO 2
Cmd_AddCommand ("vmprofile", VM_VmProfile_f );
Cmd_AddCommand ("vminfo", VM_VmInfo_f );
Com_Memset( vmTable, 0, sizeof( vmTable ) );
}
/*
===============
VM_ValueToSymbol
Assumes a program counter value
===============
*/
const char *VM_ValueToSymbol( vm_t *vm, int value ) {
vmSymbol_t *sym;
static char text[MAX_TOKEN_CHARS];
sym = vm->symbols;
if ( !sym ) {
return "NO SYMBOLS";
}
// find the symbol
while ( sym->next && sym->next->symValue <= value ) {
sym = sym->next;
}
if ( value == sym->symValue ) {
return sym->symName;
}
Com_sprintf( text, sizeof( text ), "%s+%i", sym->symName, value - sym->symValue );
return text;
}
/*
===============
VM_ValueToFunctionSymbol
For profiling, find the symbol behind this value
===============
*/
vmSymbol_t *VM_ValueToFunctionSymbol( vm_t *vm, int value ) {
vmSymbol_t *sym;
static vmSymbol_t nullSym;
sym = vm->symbols;
if ( !sym ) {
return &nullSym;
}
while ( sym->next && sym->next->symValue <= value ) {
sym = sym->next;
}
return sym;
}
/*
===============
VM_SymbolToValue
===============
*/
int VM_SymbolToValue( vm_t *vm, const char *symbol ) {
vmSymbol_t *sym;
for ( sym = vm->symbols ; sym ; sym = sym->next ) {
if ( !strcmp( symbol, sym->symName ) ) {
return sym->symValue;
}
}
return 0;
}
/*
=====================
VM_SymbolForCompiledPointer
=====================
*/
#if 0 // 64bit!
const char *VM_SymbolForCompiledPointer( vm_t *vm, void *code ) {
int i;
if ( code < (void *)vm->codeBase ) {
return "Before code block";
}
if ( code >= (void *)(vm->codeBase + vm->codeLength) ) {
return "After code block";
}
// find which original instruction it is after
for ( i = 0 ; i < vm->codeLength ; i++ ) {
if ( (void *)vm->instructionPointers[i] > code ) {
break;
}
}
i--;
// now look up the bytecode instruction pointer
return VM_ValueToSymbol( vm, i );
}
#endif
/*
===============
ParseHex
===============
*/
int ParseHex( const char *text ) {
int value;
int c;
value = 0;
while ( ( c = *text++ ) != 0 ) {
if ( c >= '0' && c <= '9' ) {
value = value * 16 + c - '0';
continue;
}
if ( c >= 'a' && c <= 'f' ) {
value = value * 16 + 10 + c - 'a';
continue;
}
if ( c >= 'A' && c <= 'F' ) {
value = value * 16 + 10 + c - 'A';
continue;
}
}
return value;
}
/*
===============
VM_LoadSymbols
===============
*/
void VM_LoadSymbols( vm_t *vm ) {
union {
char *c;
void *v;
} mapfile;
char *text_p, *token;
char name[MAX_QPATH];
char symbols[MAX_QPATH];
vmSymbol_t **prev, *sym;
int count;
int value;
int chars;
int segment;
int numInstructions;
// don't load symbols if not developer
if ( !com_developer->integer ) {
return;
}
COM_StripExtension(vm->name, name, sizeof(name));
Com_sprintf( symbols, sizeof( symbols ), "vm/%s.map", name );
FS_ReadFile( symbols, &mapfile.v );
if ( !mapfile.c ) {
Com_Printf( "Couldn't load symbol file: %s\n", symbols );
return;
}
numInstructions = vm->instructionCount;
// parse the symbols
text_p = mapfile.c;
prev = &vm->symbols;
count = 0;
while ( 1 ) {
token = COM_Parse( &text_p );
if ( !token[0] ) {
break;
}
segment = ParseHex( token );
if ( segment ) {
COM_Parse( &text_p );
COM_Parse( &text_p );
continue; // only load code segment values
}
token = COM_Parse( &text_p );
if ( !token[0] ) {
Com_Printf( "WARNING: incomplete line at end of file\n" );
break;
}
value = ParseHex( token );
token = COM_Parse( &text_p );
if ( !token[0] ) {
Com_Printf( "WARNING: incomplete line at end of file\n" );
break;
}
chars = strlen( token );
sym = Hunk_Alloc( sizeof( *sym ) + chars, h_high );
*prev = sym;
prev = &sym->next;
sym->next = NULL;
// convert value from an instruction number to a code offset
if ( value >= 0 && value < numInstructions ) {
value = vm->instructionPointers[value];
}
sym->symValue = value;
Q_strncpyz( sym->symName, token, chars + 1 );
count++;
}
vm->numSymbols = count;
Com_Printf( "%i symbols parsed from %s\n", count, symbols );
FS_FreeFile( mapfile.v );
}
/*
============
VM_DllSyscall
Dlls will call this directly
rcg010206 The horror; the horror.
The syscall mechanism relies on stack manipulation to get its args.
This is likely due to C's inability to pass "..." parameters to
a function in one clean chunk. On PowerPC Linux, these parameters
are not necessarily passed on the stack, so while (&arg[0] == arg)
is true, (&arg[1] == 2nd function parameter) is not necessarily
accurate, as arg's value might have been stored to the stack or
other piece of scratch memory to give it a valid address, but the
next parameter might still be sitting in a register.
Quake's syscall system also assumes that the stack grows downward,
and that any needed types can be squeezed, safely, into a signed int.
This hack below copies all needed values for an argument to a
array in memory, so that Quake can get the correct values. This can
also be used on systems where the stack grows upwards, as the
presumably standard and safe stdargs.h macros are used.
As for having enough space in a signed int for your datatypes, well,
it might be better to wait for DOOM 3 before you start porting. :)
The original code, while probably still inherently dangerous, seems
to work well enough for the platforms it already works on. Rather
than add the performance hit for those platforms, the original code
is still in use there.
For speed, we just grab 15 arguments, and don't worry about exactly
how many the syscall actually needs; the extra is thrown away.
============
*/
intptr_t QDECL VM_DllSyscall( intptr_t arg, ... ) {
#if !id386 || defined __clang__
// rcg010206 - see commentary above
intptr_t args[MAX_VMSYSCALL_ARGS];
int i;
va_list ap;
args[0] = arg;
va_start(ap, arg);
for (i = 1; i < ARRAY_LEN (args); i++)
args[i] = va_arg(ap, intptr_t);
va_end(ap);
return currentVM->systemCall( args );
#else // original id code
return currentVM->systemCall( &arg );
#endif
}
/*
=================
VM_LoadQVM
Load a .qvm file
=================
*/
vmHeader_t *VM_LoadQVM( vm_t *vm, qboolean alloc, qboolean unpure)
{
int dataLength;
int i;
char filename[MAX_QPATH];
union {
vmHeader_t *h;
void *v;
} header;
// load the image
Com_sprintf( filename, sizeof(filename), "vm/%s.qvm", vm->name );
Com_Printf( "Loading vm file %s...\n", filename );
FS_ReadFileDir(filename, vm->searchPath, unpure, &header.v);
if ( !header.h ) {
Com_Printf( "Failed.\n" );
VM_Free( vm );
Com_Printf(S_COLOR_YELLOW "Warning: Couldn't open VM file %s\n", filename);
return NULL;
}
// show where the qvm was loaded from
FS_Which(filename, vm->searchPath);
if( LittleLong( header.h->vmMagic ) == VM_MAGIC_VER2 ) {
Com_Printf( "...which has vmMagic VM_MAGIC_VER2\n" );
// byte swap the header
for ( i = 0 ; i < sizeof( vmHeader_t ) / 4 ; i++ ) {
((int *)header.h)[i] = LittleLong( ((int *)header.h)[i] );
}
// validate
if ( header.h->jtrgLength < 0
|| header.h->bssLength < 0
|| header.h->dataLength < 0
|| header.h->litLength < 0
|| header.h->codeLength <= 0 )
{
VM_Free(vm);
FS_FreeFile(header.v);
Com_Printf(S_COLOR_YELLOW "Warning: %s has bad header\n", filename);
return NULL;
}
} else if( LittleLong( header.h->vmMagic ) == VM_MAGIC ) {
// byte swap the header
// sizeof( vmHeader_t ) - sizeof( int ) is the 1.32b vm header size
for ( i = 0 ; i < ( sizeof( vmHeader_t ) - sizeof( int ) ) / 4 ; i++ ) {
((int *)header.h)[i] = LittleLong( ((int *)header.h)[i] );
}
// validate
if ( header.h->bssLength < 0
|| header.h->dataLength < 0
|| header.h->litLength < 0
|| header.h->codeLength <= 0 )
{
VM_Free(vm);
FS_FreeFile(header.v);
Com_Printf(S_COLOR_YELLOW "Warning: %s has bad header\n", filename);
return NULL;
}
} else {
VM_Free( vm );
FS_FreeFile(header.v);
Com_Printf(S_COLOR_YELLOW "Warning: %s does not have a recognisable "
"magic number in its header\n", filename);
return NULL;
}
// round up to next power of 2 so all data operations can
// be mask protected
dataLength = header.h->dataLength + header.h->litLength +
header.h->bssLength;
for ( i = 0 ; dataLength > ( 1 << i ) ; i++ ) {
}
dataLength = 1 << i;
if(alloc)
{
// allocate zero filled space for initialized and uninitialized data
vm->dataBase = Hunk_Alloc(dataLength, h_high);
vm->dataMask = dataLength - 1;
}
else
{
// clear the data, but make sure we're not clearing more than allocated
if(vm->dataMask + 1 != dataLength)
{
VM_Free(vm);
FS_FreeFile(header.v);
Com_Printf(S_COLOR_YELLOW "Warning: Data region size of %s not matching after "
"VM_Restart()\n", filename);
return NULL;
}
Com_Memset(vm->dataBase, 0, dataLength);
}
// copy the intialized data
Com_Memcpy( vm->dataBase, (byte *)header.h + header.h->dataOffset,
header.h->dataLength + header.h->litLength );
// byte swap the longs
for ( i = 0 ; i < header.h->dataLength ; i += 4 ) {
*(int *)(vm->dataBase + i) = LittleLong( *(int *)(vm->dataBase + i ) );
}
if(header.h->vmMagic == VM_MAGIC_VER2)
{
int previousNumJumpTableTargets = vm->numJumpTableTargets;
header.h->jtrgLength &= ~0x03;
vm->numJumpTableTargets = header.h->jtrgLength >> 2;
Com_Printf("Loading %d jump table targets\n", vm->numJumpTableTargets);
if(alloc)
{
vm->jumpTableTargets = Hunk_Alloc(header.h->jtrgLength, h_high);
}
else
{
if(vm->numJumpTableTargets != previousNumJumpTableTargets)
{
VM_Free(vm);
FS_FreeFile(header.v);
Com_Printf(S_COLOR_YELLOW "Warning: Jump table size of %s not matching after "
"VM_Restart()\n", filename);
return NULL;
}
Com_Memset(vm->jumpTableTargets, 0, header.h->jtrgLength);
}
Com_Memcpy(vm->jumpTableTargets, (byte *) header.h + header.h->dataOffset +
header.h->dataLength + header.h->litLength, header.h->jtrgLength);
// byte swap the longs
for ( i = 0 ; i < header.h->jtrgLength ; i += 4 ) {
*(int *)(vm->jumpTableTargets + i) = LittleLong( *(int *)(vm->jumpTableTargets + i ) );
}
}
return header.h;
}
/*
=================
VM_Restart
Reload the data, but leave everything else in place
This allows a server to do a map_restart without changing memory allocation
We need to make sure that servers can access unpure QVMs (not contained in any pak)
even if the client is pure, so take "unpure" as argument.
=================
*/
vm_t *VM_Restart(vm_t *vm, qboolean unpure)
{
vmHeader_t *header;
// DLL's can't be restarted in place
if ( vm->dllHandle ) {
char name[MAX_QPATH];
intptr_t (*systemCall)( intptr_t *parms );
systemCall = vm->systemCall;
Q_strncpyz( name, vm->name, sizeof( name ) );
VM_Free( vm );
vm = VM_Create( name, systemCall, VMI_NATIVE );
return vm;
}
// load the image
Com_Printf("VM_Restart()\n");
if(!(header = VM_LoadQVM(vm, qfalse, unpure)))
{
Com_Error(ERR_DROP, "VM_Restart failed");
return NULL;
}
// free the original file
FS_FreeFile(header);
return vm;
}
/*
================
VM_Create
If image ends in .qvm it will be interpreted, otherwise
it will attempt to load as a system dll
================
*/
vm_t *VM_Create( const char *module, intptr_t (*systemCalls)(intptr_t *),
vmInterpret_t interpret ) {
vm_t *vm;
vmHeader_t *header;
int i, remaining, retval;
char filename[MAX_OSPATH];
void *startSearch = NULL;
if ( !module || !module[0] || !systemCalls ) {
Com_Error( ERR_FATAL, "VM_Create: bad parms" );
}
remaining = Hunk_MemoryRemaining();
// see if we already have the VM
for ( i = 0 ; i < MAX_VM ; i++ ) {
if (!Q_stricmp(vmTable[i].name, module)) {
vm = &vmTable[i];
return vm;
}
}
// find a free vm
for ( i = 0 ; i < MAX_VM ; i++ ) {
if ( !vmTable[i].name[0] ) {
break;
}
}
if ( i == MAX_VM ) {
Com_Error( ERR_FATAL, "VM_Create: no free vm_t" );
}
vm = &vmTable[i];
Q_strncpyz(vm->name, module, sizeof(vm->name));
do
{
retval = FS_FindVM(&startSearch, filename, sizeof(filename), module, (interpret == VMI_NATIVE));
if(retval == VMI_NATIVE)
{
Com_Printf("Try loading dll file %s\n", filename);
vm->dllHandle = Sys_LoadGameDll(filename, &vm->entryPoint, VM_DllSyscall);
if(vm->dllHandle)
{
vm->systemCall = systemCalls;
return vm;
}
Com_Printf("Failed loading dll, trying next\n");
}
else if(retval == VMI_COMPILED)
{
vm->searchPath = startSearch;
if((header = VM_LoadQVM(vm, qtrue, qfalse)))
break;
// VM_Free overwrites the name on failed load
Q_strncpyz(vm->name, module, sizeof(vm->name));
}
} while(retval >= 0);
if(retval < 0)
return NULL;
vm->systemCall = systemCalls;
// allocate space for the jump targets, which will be filled in by the compile/prep functions
vm->instructionCount = header->instructionCount;
vm->instructionPointers = Hunk_Alloc(vm->instructionCount * sizeof(*vm->instructionPointers), h_high);
// copy or compile the instructions
vm->codeLength = header->codeLength;
vm->compiled = qfalse;
#ifdef NO_VM_COMPILED
if(interpret >= VMI_COMPILED) {
Com_Printf("Architecture doesn't have a bytecode compiler, using interpreter\n");
interpret = VMI_BYTECODE;
}
#else
if(interpret != VMI_BYTECODE)
{
vm->compiled = qtrue;
VM_Compile( vm, header );
}
#endif
// VM_Compile may have reset vm->compiled if compilation failed
if (!vm->compiled)
{
VM_PrepareInterpreter( vm, header );
}
// free the original file
FS_FreeFile( header );
// load the map file
VM_LoadSymbols( vm );
// the stack is implicitly at the end of the image
vm->programStack = vm->dataMask + 1;
vm->stackBottom = vm->programStack - PROGRAM_STACK_SIZE;
Com_Printf("%s loaded in %d bytes on the hunk\n", module, remaining - Hunk_MemoryRemaining());
return vm;
}
/*
==============
VM_Free
==============
*/
void VM_Free( vm_t *vm ) {
if(!vm) {
return;
}
if(vm->callLevel) {
if(!forced_unload) {
Com_Error( ERR_FATAL, "VM_Free(%s) on running vm", vm->name );
return;
} else {
Com_Printf( "forcefully unloading %s vm\n", vm->name );
}
}
if(vm->destroy)
vm->destroy(vm);
if ( vm->dllHandle ) {
Sys_UnloadDll( vm->dllHandle );
Com_Memset( vm, 0, sizeof( *vm ) );
}
#if 0 // now automatically freed by hunk
if ( vm->codeBase ) {
Z_Free( vm->codeBase );
}
if ( vm->dataBase ) {
Z_Free( vm->dataBase );
}
if ( vm->instructionPointers ) {
Z_Free( vm->instructionPointers );
}
#endif
Com_Memset( vm, 0, sizeof( *vm ) );
currentVM = NULL;
lastVM = NULL;
}
void VM_Clear(void) {
int i;
for (i=0;i<MAX_VM; i++) {
VM_Free(&vmTable[i]);
}
}
void VM_Forced_Unload_Start(void) {
forced_unload = 1;
}
void VM_Forced_Unload_Done(void) {
forced_unload = 0;
}
void *VM_ArgPtr( intptr_t intValue ) {
if ( !intValue ) {
return NULL;
}
// currentVM is missing on reconnect
if ( currentVM==NULL )
return NULL;
if ( currentVM->entryPoint ) {
return (void *)(currentVM->dataBase + intValue);
}
else {
return (void *)(currentVM->dataBase + (intValue & currentVM->dataMask));
}
}
void *VM_ExplicitArgPtr( vm_t *vm, intptr_t intValue ) {
if ( !intValue ) {
return NULL;
}
// currentVM is missing on reconnect here as well?
if ( currentVM==NULL )
return NULL;
//
if ( vm->entryPoint ) {
return (void *)(vm->dataBase + intValue);
}
else {
return (void *)(vm->dataBase + (intValue & vm->dataMask));
}
}
/*
==============
VM_Call
Upon a system call, the stack will look like:
sp+32 parm1
sp+28 parm0
sp+24 return value
sp+20 return address
sp+16 local1
sp+14 local0
sp+12 arg1
sp+8 arg0
sp+4 return stack
sp return address
An interpreted function will immediately execute
an OP_ENTER instruction, which will subtract space for
locals from sp
==============
*/
intptr_t QDECL VM_Call( vm_t *vm, int callnum, ... )
{
vm_t *oldVM;
intptr_t r;
int i;
if(!vm || !vm->name[0])
Com_Error(ERR_FATAL, "VM_Call with NULL vm");
oldVM = currentVM;
currentVM = vm;
lastVM = vm;
if ( vm_debugLevel ) {
Com_Printf( "VM_Call( %d )\n", callnum );
}
++vm->callLevel;
// if we have a dll loaded, call it directly
if ( vm->entryPoint ) {
//rcg010207 - see dissertation at top of VM_DllSyscall() in this file.
int args[MAX_VMMAIN_ARGS-1];
va_list ap;
va_start(ap, callnum);
for (i = 0; i < ARRAY_LEN(args); i++) {
args[i] = va_arg(ap, int);
}
va_end(ap);
r = vm->entryPoint( callnum, args[0], args[1], args[2], args[3],
args[4], args[5], args[6], args[7],
args[8], args[9], args[10], args[11]);
} else {
#if ( id386 || idsparc ) && !defined __clang__ // calling convention doesn't need conversion in some cases
#ifndef NO_VM_COMPILED
if ( vm->compiled )
r = VM_CallCompiled( vm, (int*)&callnum );
else
#endif
r = VM_CallInterpreted( vm, (int*)&callnum );
#else
struct {
int callnum;
int args[MAX_VMMAIN_ARGS-1];
} a;
va_list ap;
a.callnum = callnum;
va_start(ap, callnum);
for (i = 0; i < ARRAY_LEN(a.args); i++) {
a.args[i] = va_arg(ap, int);
}
va_end(ap);
#ifndef NO_VM_COMPILED
if ( vm->compiled )
r = VM_CallCompiled( vm, &a.callnum );
else
#endif
r = VM_CallInterpreted( vm, &a.callnum );
#endif
}
--vm->callLevel;
if ( oldVM != NULL )
currentVM = oldVM;
return r;
}
//=================================================================
static int QDECL VM_ProfileSort( const void *a, const void *b ) {
vmSymbol_t *sa, *sb;
sa = *(vmSymbol_t **)a;
sb = *(vmSymbol_t **)b;
if ( sa->profileCount < sb->profileCount ) {
return -1;
}
if ( sa->profileCount > sb->profileCount ) {
return 1;
}
return 0;
}
/*
==============
VM_VmProfile_f
==============
*/
void VM_VmProfile_f( void ) {
vm_t *vm;
vmSymbol_t **sorted, *sym;
int i;
double total;
if ( !lastVM ) {
return;
}
vm = lastVM;
if ( !vm->numSymbols ) {
return;
}
sorted = Z_Malloc( vm->numSymbols * sizeof( *sorted ) );
sorted[0] = vm->symbols;
total = sorted[0]->profileCount;
for ( i = 1 ; i < vm->numSymbols ; i++ ) {
sorted[i] = sorted[i-1]->next;
total += sorted[i]->profileCount;
}
qsort( sorted, vm->numSymbols, sizeof( *sorted ), VM_ProfileSort );
for ( i = 0 ; i < vm->numSymbols ; i++ ) {
int perc;
sym = sorted[i];
perc = 100 * (float) sym->profileCount / total;
Com_Printf( "%2i%% %9i %s\n", perc, sym->profileCount, sym->symName );
sym->profileCount = 0;
}
Com_Printf(" %9.0f total\n", total );
Z_Free( sorted );
}
/*
==============
VM_VmInfo_f
==============
*/
void VM_VmInfo_f( void ) {
vm_t *vm;
int i;
Com_Printf( "Registered virtual machines:\n" );
for ( i = 0 ; i < MAX_VM ; i++ ) {
vm = &vmTable[i];
if ( !vm->name[0] ) {
break;
}
Com_Printf( "%s : ", vm->name );
if ( vm->dllHandle ) {
Com_Printf( "native\n" );
continue;
}
if ( vm->compiled ) {
Com_Printf( "compiled on load\n" );
} else {
Com_Printf( "interpreted\n" );
}
Com_Printf( " code length : %7i\n", vm->codeLength );
Com_Printf( " table length: %7i\n", vm->instructionCount*4 );
Com_Printf( " data length : %7i\n", vm->dataMask + 1 );
}
}
/*
===============
VM_LogSyscalls
Insert calls to this while debugging the vm compiler
===============
*/
void VM_LogSyscalls( int *args ) {
static int callnum;
static FILE *f;
if ( !f ) {
f = fopen("syscalls.log", "w" );
}
callnum++;
fprintf(f, "%i: %p (%i) = %i %i %i %i\n", callnum, (void*)(args - (int *)currentVM->dataBase),
args[0], args[1], args[2], args[3], args[4] );
}
/*
=================
VM_BlockCopy
Executes a block copy operation within currentVM data space
=================
*/
void VM_BlockCopy(unsigned int dest, unsigned int src, size_t n)
{
unsigned int dataMask = currentVM->dataMask;
if ((dest & dataMask) != dest
|| (src & dataMask) != src
|| ((dest + n) & dataMask) != dest + n
|| ((src + n) & dataMask) != src + n)
{
Com_Error(ERR_DROP, "OP_BLOCK_COPY out of range!");
}
Com_Memcpy(currentVM->dataBase + dest, currentVM->dataBase + src, n);
}
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