2 * Emulation of priviledged instructions
4 * Copyright 1995 Alexandre Julliard
11 #include "registers.h"
14 #define STACK_reg(context) \
15 ((GET_SEL_FLAGS(SS_reg(context)) & LDT_FLAGS_32BIT) ? \
16 ESP_reg(context) : SP_reg(context))
18 #define STACK_PTR(context) \
19 (PTR_SEG_OFF_TO_LIN(SS_reg(context),STACK_reg(context)))
21 /***********************************************************************
22 * INSTR_ReplaceSelector
24 * Try to replace an invalid selector by a valid one.
25 * For now, only selector 0x40 is handled here.
27 static WORD
INSTR_ReplaceSelector( struct sigcontext_struct
*context
, WORD sel
)
31 fprintf( stderr
, "Direct access to segment 0x40 (cs:ip=%04x:%04lx).\n",
32 CS_reg(context
), EIP_reg(context
) );
33 DOSMEM_Alarm(); /* Increment BIOS clock */
34 return DOSMEM_BiosSeg
;
36 return 0; /* Can't replace selector */
40 /***********************************************************************
41 * INSTR_GetOperandAddr
43 * Return the address of an instruction operand (from the mod/rm byte).
45 static BYTE
*INSTR_GetOperandAddr( struct sigcontext_struct
*context
,
46 BYTE
*instr
, int long_addr
,
47 int segprefix
, int *len
)
49 int mod
, rm
, base
, index
= 0, ss
= 0, seg
= 0, off
;
51 #define GET_VAL(val,type) \
52 { *val = *(type *)instr; instr += sizeof(type); *len += sizeof(type); }
55 GET_VAL( &mod
, BYTE
);
63 case 0: return (BYTE
*)&EAX_reg(context
);
64 case 1: return (BYTE
*)&ECX_reg(context
);
65 case 2: return (BYTE
*)&EDX_reg(context
);
66 case 3: return (BYTE
*)&EBX_reg(context
);
67 case 4: return (BYTE
*)&ESP_reg(context
);
68 case 5: return (BYTE
*)&EBP_reg(context
);
69 case 6: return (BYTE
*)&ESI_reg(context
);
70 case 7: return (BYTE
*)&EDI_reg(context
);
79 GET_VAL( &sib
, BYTE
);
84 case 0: index
= EAX_reg(context
); break;
85 case 1: index
= ECX_reg(context
); break;
86 case 2: index
= EDX_reg(context
); break;
87 case 3: index
= EBX_reg(context
); break;
88 case 4: index
= 0; break;
89 case 5: index
= EBP_reg(context
); break;
90 case 6: index
= ESI_reg(context
); break;
91 case 7: index
= EDI_reg(context
); break;
97 case 0: base
= EAX_reg(context
); seg
= DS_reg(context
); break;
98 case 1: base
= ECX_reg(context
); seg
= DS_reg(context
); break;
99 case 2: base
= EDX_reg(context
); seg
= DS_reg(context
); break;
100 case 3: base
= EBX_reg(context
); seg
= DS_reg(context
); break;
101 case 4: base
= ESP_reg(context
); seg
= SS_reg(context
); break;
102 case 5: base
= EBP_reg(context
); seg
= SS_reg(context
); break;
103 case 6: base
= ESI_reg(context
); seg
= DS_reg(context
); break;
104 case 7: base
= EDI_reg(context
); seg
= DS_reg(context
); break;
109 if (rm
== 5) /* special case: ds:(disp32) */
111 GET_VAL( &base
, DWORD
);
112 seg
= DS_reg(context
);
116 case 1: /* 8-bit disp */
117 GET_VAL( &off
, BYTE
);
118 base
+= (signed char)off
;
121 case 2: /* 32-bit disp */
122 GET_VAL( &off
, DWORD
);
123 base
+= (signed long)off
;
127 else /* short address */
131 case 0: /* ds:(bx,si) */
132 base
= BX_reg(context
) + SI_reg(context
);
133 seg
= DS_reg(context
);
135 case 1: /* ds:(bx,di) */
136 base
= BX_reg(context
) + DI_reg(context
);
137 seg
= DS_reg(context
);
139 case 2: /* ss:(bp,si) */
140 base
= BP_reg(context
) + SI_reg(context
);
141 seg
= SS_reg(context
);
143 case 3: /* ss:(bp,di) */
144 base
= BP_reg(context
) + DI_reg(context
);
145 seg
= SS_reg(context
);
147 case 4: /* ds:(si) */
148 base
= SI_reg(context
);
149 seg
= DS_reg(context
);
151 case 5: /* ds:(di) */
152 base
= DI_reg(context
);
153 seg
= DS_reg(context
);
155 case 6: /* ss:(bp) */
156 base
= BP_reg(context
);
157 seg
= SS_reg(context
);
159 case 7: /* ds:(bx) */
160 base
= BX_reg(context
);
161 seg
= DS_reg(context
);
168 if (rm
== 6) /* special case: ds:(disp16) */
170 GET_VAL( &base
, WORD
);
171 seg
= DS_reg(context
);
175 case 1: /* 8-bit disp */
176 GET_VAL( &off
, BYTE
);
177 base
+= (signed char)off
;
180 case 2: /* 16-bit disp */
181 GET_VAL( &off
, WORD
);
182 base
+= (signed short)off
;
187 if (segprefix
!= -1) seg
= segprefix
;
189 /* FIXME: should check limit of the segment here */
190 return (BYTE
*)PTR_SEG_OFF_TO_LIN( seg
, (base
+ (index
<< ss
)) );
194 /***********************************************************************
197 * Emulate the LDS (and LES,LFS,etc.) instruction.
199 static BOOL
INSTR_EmulateLDS( struct sigcontext_struct
*context
,
200 BYTE
*instr
, int long_op
, int long_addr
,
201 int segprefix
, int *len
)
203 BYTE
*regmodrm
= instr
+ 1 + (*instr
== 0x0f);
204 BYTE
*addr
= INSTR_GetOperandAddr( context
, regmodrm
,
205 long_addr
, segprefix
, len
);
206 WORD seg
= *(WORD
*)(addr
+ (long_op
? 4 : 2));
208 if (!(seg
= INSTR_ReplaceSelector( context
, seg
)))
209 return FALSE
; /* Unable to emulate it */
211 /* Now store the offset in the correct register */
213 switch((*regmodrm
>> 3) & 7)
216 if (long_op
) EAX_reg(context
) = *(DWORD
*)addr
;
217 else AX_reg(context
) = *(WORD
*)addr
;
220 if (long_op
) ECX_reg(context
) = *(DWORD
*)addr
;
221 else CX_reg(context
) = *(WORD
*)addr
;
224 if (long_op
) EDX_reg(context
) = *(DWORD
*)addr
;
225 else DX_reg(context
) = *(WORD
*)addr
;
228 if (long_op
) EBX_reg(context
) = *(DWORD
*)addr
;
229 else BX_reg(context
) = *(WORD
*)addr
;
232 if (long_op
) ESP_reg(context
) = *(DWORD
*)addr
;
233 else SP_reg(context
) = *(WORD
*)addr
;
236 if (long_op
) EBP_reg(context
) = *(DWORD
*)addr
;
237 else BP_reg(context
) = *(WORD
*)addr
;
240 if (long_op
) ESI_reg(context
) = *(DWORD
*)addr
;
241 else SI_reg(context
) = *(WORD
*)addr
;
244 if (long_op
) EDI_reg(context
) = *(DWORD
*)addr
;
245 else DI_reg(context
) = *(WORD
*)addr
;
249 /* Store the correct segment in the segment register */
253 case 0xc4: ES_reg(context
) = seg
; break; /* les */
254 case 0xc5: DS_reg(context
) = seg
; break; /* lds */
255 case 0x0f: switch(instr
[1])
257 case 0xb2: SS_reg(context
) = seg
; break; /* lss */
259 case 0xb4: FS_reg(context
) = seg
; break; /* lfs */
262 case 0xb5: GS_reg(context
) = seg
; break; /* lgs */
268 /* Add the opcode size to the total length */
270 *len
+= 1 + (*instr
== 0x0f);
275 /***********************************************************************
276 * INSTR_EmulateInstruction
278 * Emulate a priviledged instruction. Returns TRUE if emulation successful.
280 BOOL
INSTR_EmulateInstruction( struct sigcontext_struct
*context
)
282 int prefix
, segprefix
, prefixlen
, len
, repX
, long_op
, long_addr
;
285 long_op
= long_addr
= (GET_SEL_FLAGS(CS_reg(context
)) & LDT_FLAGS_32BIT
) != 0;
286 instr
= (BYTE
*) PTR_SEG_OFF_TO_LIN( CS_reg(context
), EIP_reg(context
) );
288 /* First handle any possible prefix */
290 segprefix
= -1; /* no prefix */
299 segprefix
= CS_reg(context
);
302 segprefix
= SS_reg(context
);
305 segprefix
= DS_reg(context
);
308 segprefix
= ES_reg(context
);
312 segprefix
= FS_reg(context
);
317 segprefix
= GS_reg(context
);
321 long_op
= !long_op
; /* opcode size prefix */
324 long_addr
= !long_addr
; /* addr size prefix */
326 case 0xf0: /* lock */
328 case 0xf2: /* repne */
331 case 0xf3: /* repe */
335 prefix
= 0; /* no more prefixes */
345 /* Now look at the actual instruction */
349 case 0x07: /* pop es */
350 case 0x17: /* pop ss */
351 case 0x1f: /* pop ds */
353 WORD seg
= *(WORD
*)STACK_PTR( context
);
354 if ((seg
= INSTR_ReplaceSelector( context
, seg
)) != 0)
358 case 0x07: ES_reg(context
) = seg
; break;
359 case 0x17: SS_reg(context
) = seg
; break;
360 case 0x1f: DS_reg(context
) = seg
; break;
362 STACK_reg(context
) += long_op
? 4 : 2;
363 EIP_reg(context
) += prefixlen
+ 1;
367 break; /* Unable to emulate it */
369 case 0x0f: /* extended instruction */
373 case 0xa1: /* pop fs */
375 WORD seg
= *(WORD
*)STACK_PTR( context
);
376 if ((seg
= INSTR_ReplaceSelector( context
, seg
)) != 0)
378 FS_reg(context
) = seg
;
379 STACK_reg(context
) += long_op
? 4 : 2;
380 EIP_reg(context
) += prefixlen
+ 2;
388 case 0xa9: /* pop gs */
390 WORD seg
= *(WORD
*)STACK_PTR( context
);
391 if ((seg
= INSTR_ReplaceSelector( context
, seg
)) != 0)
393 GS_reg(context
) = seg
;
394 STACK_reg(context
) += long_op
? 4 : 2;
395 EIP_reg(context
) += prefixlen
+ 2;
402 case 0xb2: /* lss addr,reg */
404 case 0xb4: /* lfs addr,reg */
407 case 0xb5: /* lgs addr,reg */
409 if (INSTR_EmulateLDS( context
, instr
, long_op
,
410 long_addr
, segprefix
, &len
))
412 EIP_reg(context
) += prefixlen
+ len
;
417 break; /* Unable to emulate it */
419 case 0x6c: /* insb */
420 case 0x6d: /* insw/d */
421 case 0x6e: /* outsb */
422 case 0x6f: /* outsw/d */
424 int typ
= *instr
; /* Just in case it's overwritten. */
425 int outp
= (typ
>= 0x6e);
426 unsigned long count
= repX
?
427 (long_addr
? ECX_reg(context
) : CX_reg(context
)) : 1;
428 int opsize
= (typ
& 1) ? (long_op
? 4 : 2) : 1;
429 int step
= (EFL_reg(context
) & 0x400) ? -opsize
: +opsize
;
430 int seg
= outp
? DS_reg(context
) : ES_reg(context
); /* FIXME: is this right? */
433 /* FIXME: Check segment readable. */
436 /* FIXME: Check segment writeable. */
441 ECX_reg(context
) = 0;
450 data
= PTR_SEG_OFF_TO_LIN (seg
,
451 long_addr
? ESI_reg(context
) : SI_reg(context
));
452 if (long_addr
) ESI_reg(context
) += step
;
453 else SI_reg(context
) += step
;
457 data
= PTR_SEG_OFF_TO_LIN (seg
,
458 long_addr
? EDI_reg(context
) : DI_reg(context
));
459 if (long_addr
) EDI_reg(context
) += step
;
460 else DI_reg(context
) += step
;
466 *((BYTE
*)data
) = inport( DX_reg(context
), 1);
470 *((DWORD
*)data
) = inport( DX_reg(context
), 4);
472 *((WORD
*)data
) = inport( DX_reg(context
), 2);
475 outport( DX_reg(context
), 1, *((BYTE
*)data
));
479 outport( DX_reg(context
), 4, *((DWORD
*)data
));
481 outport( DX_reg(context
), 2, *((WORD
*)data
));
485 EIP_reg(context
) += prefixlen
+ 1;
489 case 0x8e: /* mov XX,segment_reg */
491 WORD seg
= *(WORD
*)INSTR_GetOperandAddr( context
, instr
+ 1,
492 long_addr
, segprefix
, &len
);
493 if (!(seg
= INSTR_ReplaceSelector( context
, seg
)))
494 break; /* Unable to emulate it */
496 switch((instr
[1] >> 3) & 7)
499 ES_reg(context
) = seg
;
500 EIP_reg(context
) += prefixlen
+ len
+ 1;
505 SS_reg(context
) = seg
;
506 EIP_reg(context
) += prefixlen
+ len
+ 1;
509 DS_reg(context
) = seg
;
510 EIP_reg(context
) += prefixlen
+ len
+ 1;
514 FS_reg(context
) = seg
;
515 EIP_reg(context
) += prefixlen
+ len
+ 1;
520 GS_reg(context
) = seg
;
521 EIP_reg(context
) += prefixlen
+ len
+ 1;
529 break; /* Unable to emulate it */
531 case 0xc4: /* les addr,reg */
532 case 0xc5: /* lds addr,reg */
533 if (INSTR_EmulateLDS( context
, instr
, long_op
,
534 long_addr
, segprefix
, &len
))
536 EIP_reg(context
) += prefixlen
+ len
;
539 break; /* Unable to emulate it */
541 case 0xcd: /* int <XX> */
544 fprintf(stderr
, "int xx from 32-bit code is not supported.\n");
545 break; /* Unable to emulate it */
549 SEGPTR addr
= INT_GetHandler( instr
[1] );
550 WORD
*stack
= (WORD
*)STACK_PTR( context
);
551 /* Push the flags and return address on the stack */
552 *(--stack
) = FL_reg(context
);
553 *(--stack
) = CS_reg(context
);
554 *(--stack
) = IP_reg(context
) + prefixlen
+ 2;
555 STACK_reg(context
) -= 3 * sizeof(WORD
);
556 /* Jump to the interrupt handler */
557 CS_reg(context
) = HIWORD(addr
);
558 EIP_reg(context
) = LOWORD(addr
);
562 case 0xcf: /* iret */
565 DWORD
*stack
= (DWORD
*)STACK_PTR( context
);
566 EIP_reg(context
) = *stack
++;
567 CS_reg(context
) = *stack
++;
568 EFL_reg(context
) = *stack
;
569 STACK_reg(context
) += 3*sizeof(DWORD
); /* Pop the return address and flags */
573 WORD
*stack
= (WORD
*)STACK_PTR( context
);
574 EIP_reg(context
) = *stack
++;
575 CS_reg(context
) = *stack
++;
576 FL_reg(context
) = *stack
;
577 STACK_reg(context
) += 3*sizeof(WORD
); /* Pop the return address and flags */
581 case 0xe4: /* inb al,XX */
582 AL_reg(context
) = inport( instr
[1], 1 );
583 EIP_reg(context
) += prefixlen
+ 2;
586 case 0xe5: /* in (e)ax,XX */
587 if (long_op
) EAX_reg(context
) = inport( instr
[1], 4 );
588 else AX_reg(context
) = inport( instr
[1], 2 );
589 EIP_reg(context
) += prefixlen
+ 2;
592 case 0xe6: /* outb XX,al */
593 outport( instr
[1], 1, AL_reg(context
) );
594 EIP_reg(context
) += prefixlen
+ 2;
597 case 0xe7: /* out XX,(e)ax */
598 if (long_op
) outport( instr
[1], 4, EAX_reg(context
) );
599 else outport( instr
[1], 2, AX_reg(context
) );
600 EIP_reg(context
) += prefixlen
+ 2;
603 case 0xec: /* inb al,dx */
604 AL_reg(context
) = inport( DX_reg(context
), 1 );
605 EIP_reg(context
) += prefixlen
+ 1;
608 case 0xed: /* in (e)ax,dx */
609 if (long_op
) EAX_reg(context
) = inport( DX_reg(context
), 4 );
610 else AX_reg(context
) = inport( DX_reg(context
), 2 );
611 EIP_reg(context
) += prefixlen
+ 1;
614 case 0xee: /* outb dx,al */
615 outport( DX_reg(context
), 1, AL_reg(context
) );
616 EIP_reg(context
) += prefixlen
+ 1;
619 case 0xef: /* out dx,(e)ax */
620 if (long_op
) outport( DX_reg(context
), 4, EAX_reg(context
) );
621 else outport( DX_reg(context
), 2, AX_reg(context
) );
622 EIP_reg(context
) += prefixlen
+ 1;
625 case 0xfa: /* cli, ignored */
626 EIP_reg(context
) += prefixlen
+ 1;
629 case 0xfb: /* sti, ignored */
630 EIP_reg(context
) += prefixlen
+ 1;
633 fprintf(stderr
, "Unexpected Windows program segfault"
634 " - opcode = %x\n", *instr
);
635 return FALSE
; /* Unable to emulate it */