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-rw-r--r--tools/ddcprobe/x86emu/decode.c1093
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diff --git a/tools/ddcprobe/x86emu/decode.c b/tools/ddcprobe/x86emu/decode.c
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-/****************************************************************************
-*
-* Realmode X86 Emulator Library
-*
-* Copyright (C) 1996-1999 SciTech Software, Inc.
-* Copyright (C) David Mosberger-Tang
-* Copyright (C) 1999 Egbert Eich
-*
-* ========================================================================
-*
-* Permission to use, copy, modify, distribute, and sell this software and
-* its documentation for any purpose is hereby granted without fee,
-* provided that the above copyright notice appear in all copies and that
-* both that copyright notice and this permission notice appear in
-* supporting documentation, and that the name of the authors not be used
-* in advertising or publicity pertaining to distribution of the software
-* without specific, written prior permission. The authors makes no
-* representations about the suitability of this software for any purpose.
-* It is provided "as is" without express or implied warranty.
-*
-* THE AUTHORS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
-* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
-* EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
-* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
-* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
-* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
-* PERFORMANCE OF THIS SOFTWARE.
-*
-* ========================================================================
-*
-* Language: ANSI C
-* Environment: Any
-* Developer: Kendall Bennett
-*
-* Description: This file includes subroutines which are related to
-* instruction decoding and accessess of immediate data via IP. etc.
-*
-****************************************************************************/
-
-/* $XFree86: xc/extras/x86emu/src/x86emu/decode.c,v 1.11 2002/07/23 20:20:43 tsi Exp $ */
-
-#include "x86emu/x86emui.h"
-
-/*----------------------------- Implementation ----------------------------*/
-
-/****************************************************************************
-REMARKS:
-Handles any pending asychronous interrupts.
-****************************************************************************/
-static void x86emu_intr_handle(void)
-{
- u8 intno;
-
- if (M.x86.intr & INTR_SYNCH) {
- intno = M.x86.intno;
- if (_X86EMU_intrTab[intno]) {
- (*_X86EMU_intrTab[intno])(intno);
- } else {
- push_word((u16)M.x86.R_FLG);
- CLEAR_FLAG(F_IF);
- CLEAR_FLAG(F_TF);
- push_word(M.x86.R_CS);
- M.x86.R_CS = mem_access_word(intno * 4 + 2);
- push_word(M.x86.R_IP);
- M.x86.R_IP = mem_access_word(intno * 4);
- M.x86.intr = 0;
- }
- }
-}
-
-/****************************************************************************
-PARAMETERS:
-intrnum - Interrupt number to raise
-
-REMARKS:
-Raise the specified interrupt to be handled before the execution of the
-next instruction.
-****************************************************************************/
-void x86emu_intr_raise(
- u8 intrnum)
-{
- M.x86.intno = intrnum;
- M.x86.intr |= INTR_SYNCH;
-}
-
-/****************************************************************************
-REMARKS:
-Main execution loop for the emulator. We return from here when the system
-halts, which is normally caused by a stack fault when we return from the
-original real mode call.
-****************************************************************************/
-void X86EMU_exec(void)
-{
- u8 op1;
-
- M.x86.intr = 0;
- DB(x86emu_end_instr();)
-
- for (;;) {
-DB( if (CHECK_IP_FETCH())
- x86emu_check_ip_access();)
- /* If debugging, save the IP and CS values. */
- SAVE_IP_CS(M.x86.R_CS, M.x86.R_IP);
- INC_DECODED_INST_LEN(1);
- if (M.x86.intr) {
- if (M.x86.intr & INTR_HALTED) {
-DB( if (M.x86.R_SP != 0) {
- printk("halted\n");
- X86EMU_trace_regs();
- }
- else {
- if (M.x86.debug)
- printk("Service completed successfully\n");
- })
- return;
- }
- if (((M.x86.intr & INTR_SYNCH) && (M.x86.intno == 0 || M.x86.intno == 2)) ||
- !ACCESS_FLAG(F_IF)) {
- x86emu_intr_handle();
- }
- }
- op1 = (*sys_rdb)(((u32)M.x86.R_CS << 4) + (M.x86.R_IP++));
- (*x86emu_optab[op1])(op1);
- if (M.x86.debug & DEBUG_EXIT) {
- M.x86.debug &= ~DEBUG_EXIT;
- return;
- }
- }
-}
-
-/****************************************************************************
-REMARKS:
-Halts the system by setting the halted system flag.
-****************************************************************************/
-void X86EMU_halt_sys(void)
-{
- M.x86.intr |= INTR_HALTED;
-}
-
-/****************************************************************************
-PARAMETERS:
-mod - Mod value from decoded byte
-regh - Reg h value from decoded byte
-regl - Reg l value from decoded byte
-
-REMARKS:
-Raise the specified interrupt to be handled before the execution of the
-next instruction.
-
-NOTE: Do not inline this function, as (*sys_rdb) is already inline!
-****************************************************************************/
-void fetch_decode_modrm(
- int *mod,
- int *regh,
- int *regl)
-{
- int fetched;
-
-DB( if (CHECK_IP_FETCH())
- x86emu_check_ip_access();)
- fetched = (*sys_rdb)(((u32)M.x86.R_CS << 4) + (M.x86.R_IP++));
- INC_DECODED_INST_LEN(1);
- *mod = (fetched >> 6) & 0x03;
- *regh = (fetched >> 3) & 0x07;
- *regl = (fetched >> 0) & 0x07;
-}
-
-/****************************************************************************
-RETURNS:
-Immediate byte value read from instruction queue
-
-REMARKS:
-This function returns the immediate byte from the instruction queue, and
-moves the instruction pointer to the next value.
-
-NOTE: Do not inline this function, as (*sys_rdb) is already inline!
-****************************************************************************/
-u8 fetch_byte_imm(void)
-{
- u8 fetched;
-
-DB( if (CHECK_IP_FETCH())
- x86emu_check_ip_access();)
- fetched = (*sys_rdb)(((u32)M.x86.R_CS << 4) + (M.x86.R_IP++));
- INC_DECODED_INST_LEN(1);
- return fetched;
-}
-
-/****************************************************************************
-RETURNS:
-Immediate word value read from instruction queue
-
-REMARKS:
-This function returns the immediate byte from the instruction queue, and
-moves the instruction pointer to the next value.
-
-NOTE: Do not inline this function, as (*sys_rdw) is already inline!
-****************************************************************************/
-u16 fetch_word_imm(void)
-{
- u16 fetched;
-
-DB( if (CHECK_IP_FETCH())
- x86emu_check_ip_access();)
- fetched = (*sys_rdw)(((u32)M.x86.R_CS << 4) + (M.x86.R_IP));
- M.x86.R_IP += 2;
- INC_DECODED_INST_LEN(2);
- return fetched;
-}
-
-/****************************************************************************
-RETURNS:
-Immediate lone value read from instruction queue
-
-REMARKS:
-This function returns the immediate byte from the instruction queue, and
-moves the instruction pointer to the next value.
-
-NOTE: Do not inline this function, as (*sys_rdw) is already inline!
-****************************************************************************/
-u32 fetch_long_imm(void)
-{
- u32 fetched;
-
-DB( if (CHECK_IP_FETCH())
- x86emu_check_ip_access();)
- fetched = (*sys_rdl)(((u32)M.x86.R_CS << 4) + (M.x86.R_IP));
- M.x86.R_IP += 4;
- INC_DECODED_INST_LEN(4);
- return fetched;
-}
-
-/****************************************************************************
-RETURNS:
-Value of the default data segment
-
-REMARKS:
-Inline function that returns the default data segment for the current
-instruction.
-
-On the x86 processor, the default segment is not always DS if there is
-no segment override. Address modes such as -3[BP] or 10[BP+SI] all refer to
-addresses relative to SS (ie: on the stack). So, at the minimum, all
-decodings of addressing modes would have to set/clear a bit describing
-whether the access is relative to DS or SS. That is the function of the
-cpu-state-varible M.x86.mode. There are several potential states:
-
- repe prefix seen (handled elsewhere)
- repne prefix seen (ditto)
-
- cs segment override
- ds segment override
- es segment override
- fs segment override
- gs segment override
- ss segment override
-
- ds/ss select (in absense of override)
-
-Each of the above 7 items are handled with a bit in the mode field.
-****************************************************************************/
-_INLINE u32 get_data_segment(void)
-{
-#define GET_SEGMENT(segment)
- switch (M.x86.mode & SYSMODE_SEGMASK) {
- case 0: /* default case: use ds register */
- case SYSMODE_SEGOVR_DS:
- case SYSMODE_SEGOVR_DS | SYSMODE_SEG_DS_SS:
- return M.x86.R_DS;
- case SYSMODE_SEG_DS_SS: /* non-overridden, use ss register */
- return M.x86.R_SS;
- case SYSMODE_SEGOVR_CS:
- case SYSMODE_SEGOVR_CS | SYSMODE_SEG_DS_SS:
- return M.x86.R_CS;
- case SYSMODE_SEGOVR_ES:
- case SYSMODE_SEGOVR_ES | SYSMODE_SEG_DS_SS:
- return M.x86.R_ES;
- case SYSMODE_SEGOVR_FS:
- case SYSMODE_SEGOVR_FS | SYSMODE_SEG_DS_SS:
- return M.x86.R_FS;
- case SYSMODE_SEGOVR_GS:
- case SYSMODE_SEGOVR_GS | SYSMODE_SEG_DS_SS:
- return M.x86.R_GS;
- case SYSMODE_SEGOVR_SS:
- case SYSMODE_SEGOVR_SS | SYSMODE_SEG_DS_SS:
- return M.x86.R_SS;
- default:
-#ifdef DEBUG
- printk("error: should not happen: multiple overrides.\n");
-#endif
- HALT_SYS();
- return 0;
- }
-}
-
-/****************************************************************************
-PARAMETERS:
-offset - Offset to load data from
-
-RETURNS:
-Byte value read from the absolute memory location.
-
-NOTE: Do not inline this function as (*sys_rdX) is already inline!
-****************************************************************************/
-u8 fetch_data_byte(
- uint offset)
-{
-#ifdef DEBUG
- if (CHECK_DATA_ACCESS())
- x86emu_check_data_access((u16)get_data_segment(), offset);
-#endif
- return (*sys_rdb)((get_data_segment() << 4) + offset);
-}
-
-/****************************************************************************
-PARAMETERS:
-offset - Offset to load data from
-
-RETURNS:
-Word value read from the absolute memory location.
-
-NOTE: Do not inline this function as (*sys_rdX) is already inline!
-****************************************************************************/
-u16 fetch_data_word(
- uint offset)
-{
-#ifdef DEBUG
- if (CHECK_DATA_ACCESS())
- x86emu_check_data_access((u16)get_data_segment(), offset);
-#endif
- return (*sys_rdw)((get_data_segment() << 4) + offset);
-}
-
-/****************************************************************************
-PARAMETERS:
-offset - Offset to load data from
-
-RETURNS:
-Long value read from the absolute memory location.
-
-NOTE: Do not inline this function as (*sys_rdX) is already inline!
-****************************************************************************/
-u32 fetch_data_long(
- uint offset)
-{
-#ifdef DEBUG
- if (CHECK_DATA_ACCESS())
- x86emu_check_data_access((u16)get_data_segment(), offset);
-#endif
- return (*sys_rdl)((get_data_segment() << 4) + offset);
-}
-
-/****************************************************************************
-PARAMETERS:
-segment - Segment to load data from
-offset - Offset to load data from
-
-RETURNS:
-Byte value read from the absolute memory location.
-
-NOTE: Do not inline this function as (*sys_rdX) is already inline!
-****************************************************************************/
-u8 fetch_data_byte_abs(
- uint segment,
- uint offset)
-{
-#ifdef DEBUG
- if (CHECK_DATA_ACCESS())
- x86emu_check_data_access(segment, offset);
-#endif
- return (*sys_rdb)(((u32)segment << 4) + offset);
-}
-
-/****************************************************************************
-PARAMETERS:
-segment - Segment to load data from
-offset - Offset to load data from
-
-RETURNS:
-Word value read from the absolute memory location.
-
-NOTE: Do not inline this function as (*sys_rdX) is already inline!
-****************************************************************************/
-u16 fetch_data_word_abs(
- uint segment,
- uint offset)
-{
-#ifdef DEBUG
- if (CHECK_DATA_ACCESS())
- x86emu_check_data_access(segment, offset);
-#endif
- return (*sys_rdw)(((u32)segment << 4) + offset);
-}
-
-/****************************************************************************
-PARAMETERS:
-segment - Segment to load data from
-offset - Offset to load data from
-
-RETURNS:
-Long value read from the absolute memory location.
-
-NOTE: Do not inline this function as (*sys_rdX) is already inline!
-****************************************************************************/
-u32 fetch_data_long_abs(
- uint segment,
- uint offset)
-{
-#ifdef DEBUG
- if (CHECK_DATA_ACCESS())
- x86emu_check_data_access(segment, offset);
-#endif
- return (*sys_rdl)(((u32)segment << 4) + offset);
-}
-
-/****************************************************************************
-PARAMETERS:
-offset - Offset to store data at
-val - Value to store
-
-REMARKS:
-Writes a word value to an segmented memory location. The segment used is
-the current 'default' segment, which may have been overridden.
-
-NOTE: Do not inline this function as (*sys_wrX) is already inline!
-****************************************************************************/
-void store_data_byte(
- uint offset,
- u8 val)
-{
-#ifdef DEBUG
- if (CHECK_DATA_ACCESS())
- x86emu_check_data_access((u16)get_data_segment(), offset);
-#endif
- (*sys_wrb)((get_data_segment() << 4) + offset, val);
-}
-
-/****************************************************************************
-PARAMETERS:
-offset - Offset to store data at
-val - Value to store
-
-REMARKS:
-Writes a word value to an segmented memory location. The segment used is
-the current 'default' segment, which may have been overridden.
-
-NOTE: Do not inline this function as (*sys_wrX) is already inline!
-****************************************************************************/
-void store_data_word(
- uint offset,
- u16 val)
-{
-#ifdef DEBUG
- if (CHECK_DATA_ACCESS())
- x86emu_check_data_access((u16)get_data_segment(), offset);
-#endif
- (*sys_wrw)((get_data_segment() << 4) + offset, val);
-}
-
-/****************************************************************************
-PARAMETERS:
-offset - Offset to store data at
-val - Value to store
-
-REMARKS:
-Writes a long value to an segmented memory location. The segment used is
-the current 'default' segment, which may have been overridden.
-
-NOTE: Do not inline this function as (*sys_wrX) is already inline!
-****************************************************************************/
-void store_data_long(
- uint offset,
- u32 val)
-{
-#ifdef DEBUG
- if (CHECK_DATA_ACCESS())
- x86emu_check_data_access((u16)get_data_segment(), offset);
-#endif
- (*sys_wrl)((get_data_segment() << 4) + offset, val);
-}
-
-/****************************************************************************
-PARAMETERS:
-segment - Segment to store data at
-offset - Offset to store data at
-val - Value to store
-
-REMARKS:
-Writes a byte value to an absolute memory location.
-
-NOTE: Do not inline this function as (*sys_wrX) is already inline!
-****************************************************************************/
-void store_data_byte_abs(
- uint segment,
- uint offset,
- u8 val)
-{
-#ifdef DEBUG
- if (CHECK_DATA_ACCESS())
- x86emu_check_data_access(segment, offset);
-#endif
- (*sys_wrb)(((u32)segment << 4) + offset, val);
-}
-
-/****************************************************************************
-PARAMETERS:
-segment - Segment to store data at
-offset - Offset to store data at
-val - Value to store
-
-REMARKS:
-Writes a word value to an absolute memory location.
-
-NOTE: Do not inline this function as (*sys_wrX) is already inline!
-****************************************************************************/
-void store_data_word_abs(
- uint segment,
- uint offset,
- u16 val)
-{
-#ifdef DEBUG
- if (CHECK_DATA_ACCESS())
- x86emu_check_data_access(segment, offset);
-#endif
- (*sys_wrw)(((u32)segment << 4) + offset, val);
-}
-
-/****************************************************************************
-PARAMETERS:
-segment - Segment to store data at
-offset - Offset to store data at
-val - Value to store
-
-REMARKS:
-Writes a long value to an absolute memory location.
-
-NOTE: Do not inline this function as (*sys_wrX) is already inline!
-****************************************************************************/
-void store_data_long_abs(
- uint segment,
- uint offset,
- u32 val)
-{
-#ifdef DEBUG
- if (CHECK_DATA_ACCESS())
- x86emu_check_data_access(segment, offset);
-#endif
- (*sys_wrl)(((u32)segment << 4) + offset, val);
-}
-
-/****************************************************************************
-PARAMETERS:
-reg - Register to decode
-
-RETURNS:
-Pointer to the appropriate register
-
-REMARKS:
-Return a pointer to the register given by the R/RM field of the
-modrm byte, for byte operands. Also enables the decoding of instructions.
-****************************************************************************/
-u8* decode_rm_byte_register(
- int reg)
-{
- switch (reg) {
- case 0:
- DECODE_PRINTF("AL");
- return &M.x86.R_AL;
- case 1:
- DECODE_PRINTF("CL");
- return &M.x86.R_CL;
- case 2:
- DECODE_PRINTF("DL");
- return &M.x86.R_DL;
- case 3:
- DECODE_PRINTF("BL");
- return &M.x86.R_BL;
- case 4:
- DECODE_PRINTF("AH");
- return &M.x86.R_AH;
- case 5:
- DECODE_PRINTF("CH");
- return &M.x86.R_CH;
- case 6:
- DECODE_PRINTF("DH");
- return &M.x86.R_DH;
- case 7:
- DECODE_PRINTF("BH");
- return &M.x86.R_BH;
- }
- HALT_SYS();
- return NULL; /* NOT REACHED OR REACHED ON ERROR */
-}
-
-/****************************************************************************
-PARAMETERS:
-reg - Register to decode
-
-RETURNS:
-Pointer to the appropriate register
-
-REMARKS:
-Return a pointer to the register given by the R/RM field of the
-modrm byte, for word operands. Also enables the decoding of instructions.
-****************************************************************************/
-u16* decode_rm_word_register(
- int reg)
-{
- switch (reg) {
- case 0:
- DECODE_PRINTF("AX");
- return &M.x86.R_AX;
- case 1:
- DECODE_PRINTF("CX");
- return &M.x86.R_CX;
- case 2:
- DECODE_PRINTF("DX");
- return &M.x86.R_DX;
- case 3:
- DECODE_PRINTF("BX");
- return &M.x86.R_BX;
- case 4:
- DECODE_PRINTF("SP");
- return &M.x86.R_SP;
- case 5:
- DECODE_PRINTF("BP");
- return &M.x86.R_BP;
- case 6:
- DECODE_PRINTF("SI");
- return &M.x86.R_SI;
- case 7:
- DECODE_PRINTF("DI");
- return &M.x86.R_DI;
- }
- HALT_SYS();
- return NULL; /* NOTREACHED OR REACHED ON ERROR */
-}
-
-/****************************************************************************
-PARAMETERS:
-reg - Register to decode
-
-RETURNS:
-Pointer to the appropriate register
-
-REMARKS:
-Return a pointer to the register given by the R/RM field of the
-modrm byte, for dword operands. Also enables the decoding of instructions.
-****************************************************************************/
-u32* decode_rm_long_register(
- int reg)
-{
- switch (reg) {
- case 0:
- DECODE_PRINTF("EAX");
- return &M.x86.R_EAX;
- case 1:
- DECODE_PRINTF("ECX");
- return &M.x86.R_ECX;
- case 2:
- DECODE_PRINTF("EDX");
- return &M.x86.R_EDX;
- case 3:
- DECODE_PRINTF("EBX");
- return &M.x86.R_EBX;
- case 4:
- DECODE_PRINTF("ESP");
- return &M.x86.R_ESP;
- case 5:
- DECODE_PRINTF("EBP");
- return &M.x86.R_EBP;
- case 6:
- DECODE_PRINTF("ESI");
- return &M.x86.R_ESI;
- case 7:
- DECODE_PRINTF("EDI");
- return &M.x86.R_EDI;
- }
- HALT_SYS();
- return NULL; /* NOTREACHED OR REACHED ON ERROR */
-}
-
-/****************************************************************************
-PARAMETERS:
-reg - Register to decode
-
-RETURNS:
-Pointer to the appropriate register
-
-REMARKS:
-Return a pointer to the register given by the R/RM field of the
-modrm byte, for word operands, modified from above for the weirdo
-special case of segreg operands. Also enables the decoding of instructions.
-****************************************************************************/
-u16* decode_rm_seg_register(
- int reg)
-{
- switch (reg) {
- case 0:
- DECODE_PRINTF("ES");
- return &M.x86.R_ES;
- case 1:
- DECODE_PRINTF("CS");
- return &M.x86.R_CS;
- case 2:
- DECODE_PRINTF("SS");
- return &M.x86.R_SS;
- case 3:
- DECODE_PRINTF("DS");
- return &M.x86.R_DS;
- case 4:
- DECODE_PRINTF("FS");
- return &M.x86.R_FS;
- case 5:
- DECODE_PRINTF("GS");
- return &M.x86.R_GS;
- case 6:
- case 7:
- DECODE_PRINTF("ILLEGAL SEGREG");
- break;
- }
- HALT_SYS();
- return NULL; /* NOT REACHED OR REACHED ON ERROR */
-}
-
-/*
- *
- * return offset from the SIB Byte
- */
-u32 decode_sib_address(int sib, int mod)
-{
- u32 base = 0, i = 0, scale = 1;
-
- switch(sib & 0x07) {
- case 0:
- DECODE_PRINTF("[EAX]");
- base = M.x86.R_EAX;
- break;
- case 1:
- DECODE_PRINTF("[ECX]");
- base = M.x86.R_ECX;
- break;
- case 2:
- DECODE_PRINTF("[EDX]");
- base = M.x86.R_EDX;
- break;
- case 3:
- DECODE_PRINTF("[EBX]");
- base = M.x86.R_EBX;
- break;
- case 4:
- DECODE_PRINTF("[ESP]");
- base = M.x86.R_ESP;
- M.x86.mode |= SYSMODE_SEG_DS_SS;
- break;
- case 5:
- if (mod == 0) {
- base = fetch_long_imm();
- DECODE_PRINTF2("%08x", base);
- } else {
- DECODE_PRINTF("[EBP]");
- base = M.x86.R_ESP;
- M.x86.mode |= SYSMODE_SEG_DS_SS;
- }
- break;
- case 6:
- DECODE_PRINTF("[ESI]");
- base = M.x86.R_ESI;
- break;
- case 7:
- DECODE_PRINTF("[EDI]");
- base = M.x86.R_EDI;
- break;
- }
- switch ((sib >> 3) & 0x07) {
- case 0:
- DECODE_PRINTF("[EAX");
- i = M.x86.R_EAX;
- break;
- case 1:
- DECODE_PRINTF("[ECX");
- i = M.x86.R_ECX;
- break;
- case 2:
- DECODE_PRINTF("[EDX");
- i = M.x86.R_EDX;
- break;
- case 3:
- DECODE_PRINTF("[EBX");
- i = M.x86.R_EBX;
- break;
- case 4:
- i = 0;
- break;
- case 5:
- DECODE_PRINTF("[EBP");
- i = M.x86.R_EBP;
- break;
- case 6:
- DECODE_PRINTF("[ESI");
- i = M.x86.R_ESI;
- break;
- case 7:
- DECODE_PRINTF("[EDI");
- i = M.x86.R_EDI;
- break;
- }
- scale = 1 << ((sib >> 6) & 0x03);
- if (((sib >> 3) & 0x07) != 4) {
- if (scale == 1) {
- DECODE_PRINTF("]");
- } else {
- DECODE_PRINTF2("*%d]", scale);
- }
- }
- return base + (i * scale);
-}
-
-/****************************************************************************
-PARAMETERS:
-rm - RM value to decode
-
-RETURNS:
-Offset in memory for the address decoding
-
-REMARKS:
-Return the offset given by mod=00 addressing. Also enables the
-decoding of instructions.
-
-NOTE: The code which specifies the corresponding segment (ds vs ss)
- below in the case of [BP+..]. The assumption here is that at the
- point that this subroutine is called, the bit corresponding to
- SYSMODE_SEG_DS_SS will be zero. After every instruction
- except the segment override instructions, this bit (as well
- as any bits indicating segment overrides) will be clear. So
- if a SS access is needed, set this bit. Otherwise, DS access
- occurs (unless any of the segment override bits are set).
-****************************************************************************/
-u32 decode_rm00_address(
- int rm)
-{
- u32 offset;
- int sib;
-
- if (M.x86.mode & SYSMODE_PREFIX_ADDR) {
- /* 32-bit addressing */
- switch (rm) {
- case 0:
- DECODE_PRINTF("[EAX]");
- return M.x86.R_EAX;
- case 1:
- DECODE_PRINTF("[ECX]");
- return M.x86.R_ECX;
- case 2:
- DECODE_PRINTF("[EDX]");
- return M.x86.R_EDX;
- case 3:
- DECODE_PRINTF("[EBX]");
- return M.x86.R_EBX;
- case 4:
- sib = fetch_byte_imm();
- return decode_sib_address(sib, 0);
- case 5:
- offset = fetch_long_imm();
- DECODE_PRINTF2("[%08x]", offset);
- return offset;
- case 6:
- DECODE_PRINTF("[ESI]");
- return M.x86.R_ESI;
- case 7:
- DECODE_PRINTF("[EDI]");
- return M.x86.R_EDI;
- }
- HALT_SYS();
- } else {
- /* 16-bit addressing */
- switch (rm) {
- case 0:
- DECODE_PRINTF("[BX+SI]");
- return (M.x86.R_BX + M.x86.R_SI) & 0xffff;
- case 1:
- DECODE_PRINTF("[BX+DI]");
- return (M.x86.R_BX + M.x86.R_DI) & 0xffff;
- case 2:
- DECODE_PRINTF("[BP+SI]");
- M.x86.mode |= SYSMODE_SEG_DS_SS;
- return (M.x86.R_BP + M.x86.R_SI) & 0xffff;
- case 3:
- DECODE_PRINTF("[BP+DI]");
- M.x86.mode |= SYSMODE_SEG_DS_SS;
- return (M.x86.R_BP + M.x86.R_DI) & 0xffff;
- case 4:
- DECODE_PRINTF("[SI]");
- return M.x86.R_SI;
- case 5:
- DECODE_PRINTF("[DI]");
- return M.x86.R_DI;
- case 6:
- offset = fetch_word_imm();
- DECODE_PRINTF2("[%04x]", offset);
- return offset;
- case 7:
- DECODE_PRINTF("[BX]");
- return M.x86.R_BX;
- }
- HALT_SYS();
- }
- return 0;
-}
-
-/****************************************************************************
-PARAMETERS:
-rm - RM value to decode
-
-RETURNS:
-Offset in memory for the address decoding
-
-REMARKS:
-Return the offset given by mod=01 addressing. Also enables the
-decoding of instructions.
-****************************************************************************/
-u32 decode_rm01_address(
- int rm)
-{
- int displacement = 0;
- int sib;
-
- /* Fetch disp8 if no SIB byte */
- if (!((M.x86.mode & SYSMODE_PREFIX_ADDR) && (rm == 4)))
- displacement = (s8)fetch_byte_imm();
-
- if (M.x86.mode & SYSMODE_PREFIX_ADDR) {
- /* 32-bit addressing */
- switch (rm) {
- case 0:
- DECODE_PRINTF2("%d[EAX]", displacement);
- return M.x86.R_EAX + displacement;
- case 1:
- DECODE_PRINTF2("%d[ECX]", displacement);
- return M.x86.R_ECX + displacement;
- case 2:
- DECODE_PRINTF2("%d[EDX]", displacement);
- return M.x86.R_EDX + displacement;
- case 3:
- DECODE_PRINTF2("%d[EBX]", displacement);
- return M.x86.R_EBX + displacement;
- case 4:
- sib = fetch_byte_imm();
- displacement = (s8)fetch_byte_imm();
- DECODE_PRINTF2("%d", displacement);
- return decode_sib_address(sib, 1) + displacement;
- case 5:
- DECODE_PRINTF2("%d[EBP]", displacement);
- return M.x86.R_EBP + displacement;
- case 6:
- DECODE_PRINTF2("%d[ESI]", displacement);
- return M.x86.R_ESI + displacement;
- case 7:
- DECODE_PRINTF2("%d[EDI]", displacement);
- return M.x86.R_EDI + displacement;
- }
- HALT_SYS();
- } else {
- /* 16-bit addressing */
- switch (rm) {
- case 0:
- DECODE_PRINTF2("%d[BX+SI]", displacement);
- return (M.x86.R_BX + M.x86.R_SI + displacement) & 0xffff;
- case 1:
- DECODE_PRINTF2("%d[BX+DI]", displacement);
- return (M.x86.R_BX + M.x86.R_DI + displacement) & 0xffff;
- case 2:
- DECODE_PRINTF2("%d[BP+SI]", displacement);
- M.x86.mode |= SYSMODE_SEG_DS_SS;
- return (M.x86.R_BP + M.x86.R_SI + displacement) & 0xffff;
- case 3:
- DECODE_PRINTF2("%d[BP+DI]", displacement);
- M.x86.mode |= SYSMODE_SEG_DS_SS;
- return (M.x86.R_BP + M.x86.R_DI + displacement) & 0xffff;
- case 4:
- DECODE_PRINTF2("%d[SI]", displacement);
- return (M.x86.R_SI + displacement) & 0xffff;
- case 5:
- DECODE_PRINTF2("%d[DI]", displacement);
- return (M.x86.R_DI + displacement) & 0xffff;
- case 6:
- DECODE_PRINTF2("%d[BP]", displacement);
- M.x86.mode |= SYSMODE_SEG_DS_SS;
- return (M.x86.R_BP + displacement) & 0xffff;
- case 7:
- DECODE_PRINTF2("%d[BX]", displacement);
- return (M.x86.R_BX + displacement) & 0xffff;
- }
- HALT_SYS();
- }
- return 0; /* SHOULD NOT HAPPEN */
-}
-
-/****************************************************************************
-PARAMETERS:
-rm - RM value to decode
-
-RETURNS:
-Offset in memory for the address decoding
-
-REMARKS:
-Return the offset given by mod=10 addressing. Also enables the
-decoding of instructions.
-****************************************************************************/
-u32 decode_rm10_address(
- int rm)
-{
- u32 displacement = 0;
- int sib;
-
- /* Fetch disp16 if 16-bit addr mode */
- if (!(M.x86.mode & SYSMODE_PREFIX_ADDR))
- displacement = (u16)fetch_word_imm();
- else {
- /* Fetch disp32 if no SIB byte */
- if (rm != 4)
- displacement = (u32)fetch_long_imm();
- }
-
- if (M.x86.mode & SYSMODE_PREFIX_ADDR) {
- /* 32-bit addressing */
- switch (rm) {
- case 0:
- DECODE_PRINTF2("%08x[EAX]", displacement);
- return M.x86.R_EAX + displacement;
- case 1:
- DECODE_PRINTF2("%08x[ECX]", displacement);
- return M.x86.R_ECX + displacement;
- case 2:
- DECODE_PRINTF2("%08x[EDX]", displacement);
- M.x86.mode |= SYSMODE_SEG_DS_SS;
- return M.x86.R_EDX + displacement;
- case 3:
- DECODE_PRINTF2("%08x[EBX]", displacement);
- return M.x86.R_EBX + displacement;
- case 4:
- sib = fetch_byte_imm();
- displacement = (u32)fetch_long_imm();
- DECODE_PRINTF2("%08x", displacement);
- return decode_sib_address(sib, 2) + displacement;
- break;
- case 5:
- DECODE_PRINTF2("%08x[EBP]", displacement);
- return M.x86.R_EBP + displacement;
- case 6:
- DECODE_PRINTF2("%08x[ESI]", displacement);
- return M.x86.R_ESI + displacement;
- case 7:
- DECODE_PRINTF2("%08x[EDI]", displacement);
- return M.x86.R_EDI + displacement;
- }
- HALT_SYS();
- } else {
- /* 16-bit addressing */
- switch (rm) {
- case 0:
- DECODE_PRINTF2("%04x[BX+SI]", displacement);
- return (M.x86.R_BX + M.x86.R_SI + displacement) & 0xffff;
- case 1:
- DECODE_PRINTF2("%04x[BX+DI]", displacement);
- return (M.x86.R_BX + M.x86.R_DI + displacement) & 0xffff;
- case 2:
- DECODE_PRINTF2("%04x[BP+SI]", displacement);
- M.x86.mode |= SYSMODE_SEG_DS_SS;
- return (M.x86.R_BP + M.x86.R_SI + displacement) & 0xffff;
- case 3:
- DECODE_PRINTF2("%04x[BP+DI]", displacement);
- M.x86.mode |= SYSMODE_SEG_DS_SS;
- return (M.x86.R_BP + M.x86.R_DI + displacement) & 0xffff;
- case 4:
- DECODE_PRINTF2("%04x[SI]", displacement);
- return (M.x86.R_SI + displacement) & 0xffff;
- case 5:
- DECODE_PRINTF2("%04x[DI]", displacement);
- return (M.x86.R_DI + displacement) & 0xffff;
- case 6:
- DECODE_PRINTF2("%04x[BP]", displacement);
- M.x86.mode |= SYSMODE_SEG_DS_SS;
- return (M.x86.R_BP + displacement) & 0xffff;
- case 7:
- DECODE_PRINTF2("%04x[BX]", displacement);
- return (M.x86.R_BX + displacement) & 0xffff;
- }
- HALT_SYS();
- }
- return 0;
- /*NOTREACHED */
-}