166 lines
6.3 KiB
C
Executable File
166 lines
6.3 KiB
C
Executable File
/////////////////////////////////////////////////////////////////////////
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// $Id: descriptor.h
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/////////////////////////////////////////////////////////////////////////
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//
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// Copyright (C) 2001 MandrakeSoft S.A.
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//
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// MandrakeSoft S.A.
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// 43, rue d'Aboukir
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// 75002 Paris - France
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// http://www.linux-mandrake.com/
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// http://www.mandrakesoft.com/
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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 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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/////////////////////////////////////////////////////////////////////////
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#ifndef BX_DESCRIPTOR_H
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#define BX_DESCRIPTOR_H
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typedef struct { /* bx_selector_t */
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Bit16u value; /* the 16bit value of the selector */
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#if BX_CPU_LEVEL >= 2
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/* the following fields are extracted from the value field in protected
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mode only. They're used for sake of efficiency */
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Bit16u index; /* 13bit index extracted from value in protected mode */
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Bit8u ti; /* table indicator bit extracted from value */
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Bit8u rpl; /* RPL extracted from value */
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#endif
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} bx_selector_t;
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#define BX_SELECTOR_RPL_MASK (0xfffc)
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typedef struct
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{
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bx_bool valid; // Holds above values, Or'd together. Used to
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// hold only 0 or 1.
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#define SegValidCache (0x1)
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#define SegAccessROK (0x2)
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#define SegAccessWOK (0x4)
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bx_bool p; /* present */
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Bit8u dpl; /* descriptor privilege level 0..3 */
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bx_bool segment; /* 0 = system/gate, 1 = data/code segment */
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Bit8u type; /* For system & gate descriptors, only
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* 0 = invalid descriptor (reserved)
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* 1 = 286 available Task State Segment (TSS)
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* 2 = LDT descriptor
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* 3 = 286 busy Task State Segment (TSS)
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* 4 = 286 call gate
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* 5 = task gate
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* 6 = 286 interrupt gate
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* 7 = 286 trap gate
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* 8 = (reserved)
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* 9 = 386 available TSS
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* 10 = (reserved)
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* 11 = 386 busy TSS
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* 12 = 386 call gate
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* 13 = (reserved)
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* 14 = 386 interrupt gate
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* 15 = 386 trap gate */
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#define BX_GATE_TYPE_NONE (0x0)
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#define BX_SYS_SEGMENT_AVAIL_286_TSS (0x1)
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#define BX_SYS_SEGMENT_LDT (0x2)
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#define BX_SYS_SEGMENT_BUSY_286_TSS (0x3)
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#define BX_286_CALL_GATE (0x4)
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#define BX_TASK_GATE (0x5)
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#define BX_286_INTERRUPT_GATE (0x6)
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#define BX_286_TRAP_GATE (0x7)
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/* 0x8 reserved */
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#define BX_SYS_SEGMENT_AVAIL_386_TSS (0x9)
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/* 0xa reserved */
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#define BX_SYS_SEGMENT_BUSY_386_TSS (0xb)
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#define BX_386_CALL_GATE (0xc)
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/* 0xd reserved */
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#define BX_386_INTERRUPT_GATE (0xe)
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#define BX_386_TRAP_GATE (0xf)
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union {
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struct {
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bx_bool executable; /* 1=code, 0=data or stack segment */
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bx_bool c_ed; /* for code: 1=conforming,
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for data/stack: 1=expand down */
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bx_bool r_w; /* for code: readable?, for data/stack: writeable? */
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bx_bool a; /* accessed? */
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bx_address base; /* base address: 286=24bits, 386=32bits, long=64 */
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Bit32u limit; /* limit: 286=16bits, 386=20bits */
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Bit32u limit_scaled; /* for efficiency, this contrived field is set to
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* limit for byte granular, and
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* (limit << 12) | 0xfff for page granular seg's
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*/
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#if BX_CPU_LEVEL >= 3
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bx_bool g; /* granularity: 0=byte, 1=4K (page) */
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bx_bool d_b; /* default size: 0=16bit, 1=32bit */
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#if BX_SUPPORT_X86_64
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bx_bool l; /* long mode: 0=compat, 1=64 bit */
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#endif
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bx_bool avl; /* available for use by system */
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#endif
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} segment;
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struct {
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Bit8u word_count; /* 5bits (0..31) #words to copy from caller's stack
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* to called procedure's stack. (call gates only)*/
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Bit16u dest_selector;
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Bit16u dest_offset;
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} gate286;
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struct { // type 5: Task Gate Descriptor
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Bit16u tss_selector; // TSS segment selector
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} taskgate;
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#if BX_CPU_LEVEL >= 3
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struct {
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Bit8u dword_count; /* 5bits (0..31) #dwords to copy from caller's stack
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* to called procedure's stack. (call gates only)*/
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Bit16u dest_selector;
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Bit32u dest_offset;
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} gate386;
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#endif
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struct {
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Bit32u base; /* 24 bit 286 TSS base */
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Bit16u limit; /* 16 bit 286 TSS limit */
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} tss286;
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#if BX_CPU_LEVEL >= 3
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struct {
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bx_address base; /* 32/64 bit 386 TSS base */
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Bit32u limit; /* 20 bit 386 TSS limit */
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Bit32u limit_scaled; // Same notes as for 'segment' field
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bx_bool g; /* granularity: 0=byte, 1=4K (page) */
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bx_bool avl; /* available for use by system */
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} tss386;
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#endif
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struct {
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bx_address base; /* 286=24 386+ =32/64 bit LDT base */
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Bit16u limit; /* 286+ =16 bit LDT limit */
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} ldt;
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} u;
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} bx_descriptor_t;
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typedef struct {
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bx_selector_t selector;
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bx_descriptor_t cache;
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} bx_segment_reg_t;
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#if BX_CPU_LEVEL < 2
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/* no GDTR or IDTR register in an 8086 */
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#else
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typedef struct {
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bx_address base; /* base address: 24bits=286,32bits=386,64bits=x86-64 */
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Bit16u limit; /* limit, 16bits */
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} bx_global_segment_reg_t;
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#endif
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#endif
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