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300 lines
9.1 KiB
C
300 lines
9.1 KiB
C
/*
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* DOS upper memory management.
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*
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* Copyright 2002 Jukka Heinonen
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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#include "dosexe.h"
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#include "wine/debug.h"
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WINE_DEFAULT_DEBUG_CHANNEL(dosmem);
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/*
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* Wine DOS memory layout above 640k:
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*
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* a0000 - affff : VGA graphics (vga.c)
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* b0000 - bffff : Monochrome text (unused)
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* b8000 - bffff : VGA text (vga.c)
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* c0000 - cffff : EMS frame (int67.c)
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* d0000 - effff : Free memory for UMBs (himem.c)
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* f0000 - fffff : BIOS stuff (msdos/dosmem.c)
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* 100000 -10ffff : High memory area (unused)
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*/
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/*
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* Table of real mode segments and protected mode selectors
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* for code stubs and other miscellaneous storage.
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*/
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struct DPMI_segments *DOSVM_dpmi_segments = NULL;
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/*
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* First and last address available for upper memory blocks.
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*/
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#define DOSVM_UMB_BOTTOM 0xd0000
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#define DOSVM_UMB_TOP 0xeffff
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/*
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* First free address for upper memory blocks.
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*/
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static DWORD DOSVM_umb_free = DOSVM_UMB_BOTTOM;
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/***********************************************************************
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* DOSVM_AllocUMB
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*
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* Allocate upper memory block (UMB) from upper memory.
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* Returned pointer is aligned to 16-byte (paragraph) boundary.
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*
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* This routine is only for allocating static storage for
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* Wine internal uses. Allocated memory can be accessed from
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* real mode, memory is taken from area already mapped and reserved
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* by Wine and the allocation has very little memory and speed
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* overhead. Use of this routine also preserves precious DOS
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* conventional memory.
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*/
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LPVOID DOSVM_AllocUMB( DWORD size )
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{
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LPVOID ptr = (LPVOID)DOSVM_umb_free;
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size = ((size + 15) >> 4) << 4;
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if(DOSVM_umb_free + size - 1 > DOSVM_UMB_TOP) {
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ERR("Out of upper memory area.\n");
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return 0;
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}
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DOSVM_umb_free += size;
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return ptr;
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}
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/**********************************************************************
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* alloc_selector
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*
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* Allocate a selector corresponding to a real mode address.
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* size must be < 64k.
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*/
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static WORD alloc_selector( void *base, DWORD size, unsigned char flags )
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{
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WORD sel = wine_ldt_alloc_entries( 1 );
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if (sel)
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{
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LDT_ENTRY entry;
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wine_ldt_set_base( &entry, base );
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wine_ldt_set_limit( &entry, size - 1 );
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wine_ldt_set_flags( &entry, flags );
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wine_ldt_set_entry( sel, &entry );
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}
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return sel;
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}
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/***********************************************************************
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* DOSVM_AllocCodeUMB
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*
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* Allocate upper memory block for storing code stubs.
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* Initializes real mode segment and 16-bit protected mode selector
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* for the allocated code block.
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*
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* FIXME: should allocate a single PM selector for the whole UMB range.
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*/
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LPVOID DOSVM_AllocCodeUMB( DWORD size, WORD *segment, WORD *selector )
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{
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LPVOID ptr = DOSVM_AllocUMB( size );
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if (segment)
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*segment = (DWORD)ptr >> 4;
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if (selector)
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*selector = alloc_selector( ptr, size, WINE_LDT_FLAGS_CODE );
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return ptr;
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}
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/***********************************************************************
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* DOSVM_AllocDataUMB
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*
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* Allocate upper memory block for storing data.
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* Initializes real mode segment and 16-bit protected mode selector
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* for the allocated data block.
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*/
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LPVOID DOSVM_AllocDataUMB( DWORD size, WORD *segment, WORD *selector )
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{
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LPVOID ptr = DOSVM_AllocUMB( size );
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if (segment)
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*segment = (DWORD)ptr >> 4;
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if (selector)
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*selector = alloc_selector( ptr, size, WINE_LDT_FLAGS_DATA );
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return ptr;
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}
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/***********************************************************************
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* DOSVM_InitSegments
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*
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* Initializes DOSVM_dpmi_segments. Allocates required memory and
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* sets up segments and selectors for accessing the memory.
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*/
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void DOSVM_InitSegments( void )
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{
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LPSTR ptr;
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int i;
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static const char wrap_code[]={
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0xCD,0x31, /* int $0x31 */
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0xCB /* lret */
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};
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static const char enter_xms[]=
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{
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/* XMS hookable entry point */
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0xEB,0x03, /* jmp entry */
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0x90,0x90,0x90, /* nop;nop;nop */
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/* entry: */
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/* real entry point */
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/* for simplicity, we'll just use the same hook as DPMI below */
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0xCD,0x31, /* int $0x31 */
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0xCB /* lret */
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};
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static const char enter_pm[]=
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{
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0x50, /* pushw %ax */
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0x52, /* pushw %dx */
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0x55, /* pushw %bp */
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0x89,0xE5, /* movw %sp,%bp */
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/* get return CS */
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0x8B,0x56,0x08, /* movw 8(%bp),%dx */
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/* just call int 31 here to get into protected mode... */
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/* it'll check whether it was called from dpmi_seg... */
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0xCD,0x31, /* int $0x31 */
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/* we are now in the context of a 16-bit relay call */
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/* need to fixup our stack;
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* 16-bit relay return address will be lost,
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* but we won't worry quite yet
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*/
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0x8E,0xD0, /* movw %ax,%ss */
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0x66,0x0F,0xB7,0xE5, /* movzwl %bp,%esp */
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/* set return CS */
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0x89,0x56,0x08, /* movw %dx,8(%bp) */
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0x5D, /* popw %bp */
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0x5A, /* popw %dx */
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0x58, /* popw %ax */
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0xfb, /* sti, enable and check virtual interrupts */
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0xCB /* lret */
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};
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static const char relay[]=
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{
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0xca, 0x04, 0x00, /* 16-bit far return and pop 4 bytes (relay void* arg) */
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0xcd, 0x31, /* int 31 */
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0xfb, 0x66, 0xcb /* sti and 32-bit far return */
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};
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/*
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* Allocate pointer array.
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*/
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DOSVM_dpmi_segments = DOSVM_AllocUMB( sizeof(struct DPMI_segments) );
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/*
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* RM / offset 0: Exit from real mode.
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* RM / offset 2: Points to lret opcode.
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*/
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ptr = DOSVM_AllocCodeUMB( sizeof(wrap_code),
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&DOSVM_dpmi_segments->wrap_seg, 0 );
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memcpy( ptr, wrap_code, sizeof(wrap_code) );
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/*
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* RM / offset 0: XMS driver entry.
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*/
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ptr = DOSVM_AllocCodeUMB( sizeof(enter_xms),
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&DOSVM_dpmi_segments->xms_seg, 0 );
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memcpy( ptr, enter_xms, sizeof(enter_xms) );
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/*
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* RM / offset 0: Switch to DPMI.
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* PM / offset 8: DPMI raw mode switch.
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*/
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ptr = DOSVM_AllocCodeUMB( sizeof(enter_pm),
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&DOSVM_dpmi_segments->dpmi_seg,
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&DOSVM_dpmi_segments->dpmi_sel );
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memcpy( ptr, enter_pm, sizeof(enter_pm) );
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/*
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* PM / offset N*6: Interrupt N in DPMI32.
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*/
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ptr = DOSVM_AllocCodeUMB( 6 * 256,
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0, &DOSVM_dpmi_segments->int48_sel );
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for(i=0; i<256; i++) {
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/*
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* Each 32-bit interrupt handler is 6 bytes:
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* 0xCD,<i> = int <i> (nested 16-bit interrupt)
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* 0x66,0xCA,0x04,0x00 = ret 4 (32-bit far return and pop 4 bytes / eflags)
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*/
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ptr[i * 6 + 0] = 0xCD;
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ptr[i * 6 + 1] = i;
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ptr[i * 6 + 2] = 0x66;
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ptr[i * 6 + 3] = 0xCA;
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ptr[i * 6 + 4] = 0x04;
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ptr[i * 6 + 5] = 0x00;
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}
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/*
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* PM / offset N*5: Interrupt N in 16-bit protected mode.
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*/
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ptr = DOSVM_AllocCodeUMB( 5 * 256,
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0, &DOSVM_dpmi_segments->int16_sel );
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for(i=0; i<256; i++) {
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/*
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* Each 16-bit interrupt handler is 5 bytes:
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* 0xCD,<i> = int <i> (interrupt)
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* 0xCA,0x02,0x00 = ret 2 (16-bit far return and pop 2 bytes / eflags)
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*/
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ptr[i * 5 + 0] = 0xCD;
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ptr[i * 5 + 1] = i;
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ptr[i * 5 + 2] = 0xCA;
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ptr[i * 5 + 3] = 0x02;
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ptr[i * 5 + 4] = 0x00;
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}
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/*
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* PM / offset 0: Stub where __wine_call_from_16_regs returns.
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* PM / offset 3: Stub which swaps back to 32-bit application code/stack.
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* PM / offset 5: Stub which enables interrupts
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*/
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ptr = DOSVM_AllocCodeUMB( sizeof(relay),
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0, &DOSVM_dpmi_segments->relay_code_sel);
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memcpy( ptr, relay, sizeof(relay) );
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/*
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* Space for 16-bit stack used by relay code.
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*/
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ptr = DOSVM_AllocDataUMB( DOSVM_RELAY_DATA_SIZE,
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0, &DOSVM_dpmi_segments->relay_data_sel);
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memset( ptr, 0, DOSVM_RELAY_DATA_SIZE );
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/*
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* As we store code in UMB we should make sure it is executable
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*/
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VirtualProtect((void *)DOSVM_UMB_BOTTOM, DOSVM_UMB_TOP - DOSVM_UMB_BOTTOM, PAGE_EXECUTE_READWRITE, NULL);
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}
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