257 lines
6.3 KiB
C
257 lines
6.3 KiB
C
/*
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* Emulation of priviledged instructions
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*
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* Copyright 1995 Alexandre Julliard
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*/
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#include <stdio.h>
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#include "windows.h"
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#include "ldt.h"
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#include "miscemu.h"
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#include "registers.h"
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/***********************************************************************
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* INSTR_EmulateInstruction
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*
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* Emulate a priviledged instruction. Returns TRUE if emulation successful.
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*/
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BOOL INSTR_EmulateInstruction( struct sigcontext_struct *context )
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{
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int prefix, segprefix, repX, long_op, long_addr;
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BYTE *instr;
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long_op = long_addr = (GET_SEL_FLAGS(CS) & LDT_FLAGS_32BIT) != 0;
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instr = (BYTE *) PTR_SEG_OFF_TO_LIN( CS, long_op ? EIP : IP );
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/* First handle any possible prefix */
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segprefix = -1; /* no prefix */
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prefix = 1;
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repX = 0;
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while(prefix)
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{
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switch(*instr)
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{
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case 0x2e:
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segprefix = CS;
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break;
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case 0x36:
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segprefix = SS;
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break;
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case 0x3e:
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segprefix = DS;
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break;
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case 0x26:
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segprefix = ES;
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break;
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case 0x64:
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segprefix = FS;
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break;
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case 0x65:
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segprefix = GS;
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break;
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case 0x66:
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long_op = !long_op; /* opcode size prefix */
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break;
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case 0x67:
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long_addr = !long_addr; /* addr size prefix */
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break;
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case 0xf0: /* lock */
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break;
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case 0xf2: /* repne */
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repX = 1;
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break;
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case 0xf3: /* repe */
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repX = 2;
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break;
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default:
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prefix = 0; /* no more prefixes */
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break;
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}
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if (prefix)
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{
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instr++;
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EIP++;
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}
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}
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/* Now look at the actual instruction */
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switch(*instr)
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{
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case 0xcd: /* int <XX> */
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if (long_op)
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{
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fprintf(stderr, "int xx from 32-bit code is not supported.\n");
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return FALSE; /* Unable to emulate it */
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}
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else
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{
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SEGPTR addr = INT_GetHandler( instr[1] );
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/* FIXME: should check the stack 'big' bit */
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WORD *stack = (WORD *)PTR_SEG_OFF_TO_LIN( SS, SP );
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/* Push the flags and return address on the stack */
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*(--stack) = FL;
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*(--stack) = CS;
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*(--stack) = IP + 2;
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SP -= 3 * sizeof(WORD);
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/* Jump to the interrupt handler */
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CS = HIWORD(addr);
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EIP = LOWORD(addr);
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}
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break;
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case 0xcf: /* iret */
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if (long_op)
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{
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/* FIXME: should check the stack 'big' bit */
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DWORD *stack = (DWORD *)PTR_SEG_OFF_TO_LIN( SS, SP );
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EIP = *stack++;
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CS = *stack++;
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EFL = *stack;
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SP += 3*sizeof(DWORD); /* Pop the return address and flags */
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}
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else
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{
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/* FIXME: should check the stack 'big' bit */
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WORD *stack = (WORD *)PTR_SEG_OFF_TO_LIN( SS, SP );
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EIP = *stack++;
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CS = *stack++;
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FL = *stack;
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SP += 3*sizeof(WORD); /* Pop the return address and flags */
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}
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break;
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case 0xe4: /* inb al,XX */
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AL = inport( instr[1], 1 );
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EIP += 2;
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break;
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case 0xe5: /* in (e)ax,XX */
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if (long_op) EAX = inport( instr[1], 4 );
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else AX = inport( instr[1], 2 );
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EIP += 2;
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break;
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case 0xe6: /* outb XX,al */
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outport( instr[1], 1, AL );
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EIP += 2;
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break;
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case 0xe7: /* out XX,(e)ax */
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if (long_op) outport( instr[1], 4, EAX );
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else outport( instr[1], 2, AX );
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EIP += 2;
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break;
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case 0xec: /* inb al,dx */
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AL = inport( DX, 1 );
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EIP++;
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break;
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case 0xed: /* in (e)ax,dx */
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if (long_op) EAX = inport( DX, 4 );
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else AX = inport( DX, 2 );
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EIP++;
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break;
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case 0xee: /* outb dx,al */
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outport( DX, 1, AL );
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EIP++;
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break;
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case 0xef: /* out dx,(e)ax */
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if (long_op) outport( DX, 4, EAX );
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else outport( DX, 2, AX );
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EIP++;
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break;
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case 0xfa: /* cli, ignored */
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EIP++;
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break;
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case 0xfb: /* sti, ignored */
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EIP++;
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break;
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case 0x6c: /* insb */
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case 0x6d: /* insw/d */
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case 0x6e: /* outsb */
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case 0x6f: /* outsw/d */
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{
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int typ = *instr; /* Just in case it's overwritten. */
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int outp = (typ >= 0x6e);
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unsigned long count = repX ? (long_addr ? ECX : CX) : 1;
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int opsize = (typ & 1) ? (long_op ? 4 : 2) : 1;
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int step = (EFL & 0x400) ? -opsize : +opsize;
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/* FIXME: Check this, please. */
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int seg = outp ? (segprefix >= 0 ? segprefix : DS) : ES;
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if (outp)
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/* FIXME: Check segment readable. */
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;
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else
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/* FIXME: Check segment writeable. */
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;
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if (repX)
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if (long_addr)
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ECX = 0;
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else
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CX = 0;
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while (count-- > 0)
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{
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void *data;
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if (outp)
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{
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data = PTR_SEG_OFF_TO_LIN (seg, long_addr ? ESI : SI);
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if (long_addr)
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ESI += step;
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else
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SI += step;
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}
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else
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{
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data = PTR_SEG_OFF_TO_LIN (seg, long_addr ? EDI : DI);
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if (long_addr)
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EDI += step;
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else
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DI += step;
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}
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switch (typ)
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{
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case 0x6c:
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*((BYTE *)data) = inport (DX, 1);
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break;
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case 0x6d:
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if (long_op)
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*((DWORD *)data) = inport (DX, 4);
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else
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*((WORD *)data) = inport (DX, 2);
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break;
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case 0x6e:
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outport (DX, 1, *((BYTE *)data));
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break;
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case 0x6f:
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if (long_op)
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outport (DX, 4, *((DWORD *)data));
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else
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outport (DX, 2, *((WORD *)data));
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break;
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}
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}
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EIP++;
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break;
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}
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default:
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fprintf(stderr, "Unexpected Windows program segfault"
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" - opcode = %x\n", *instr);
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return FALSE; /* Unable to emulate it */
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}
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return TRUE;
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}
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