2 * Emulation of priviledged instructions
4 * Copyright 1995 Alexandre Julliard
11 #include "sig_context.h"
14 #define STACK_sig(context) \
15 ((GET_SEL_FLAGS(SS_sig(context)) & LDT_FLAGS_32BIT) ? \
16 ESP_sig(context) : SP_sig(context))
18 #define STACK_PTR(context) \
19 (PTR_SEG_OFF_TO_LIN(SS_sig(context),STACK_sig(context)))
21 /***********************************************************************
22 * INSTR_ReplaceSelector
24 * Try to replace an invalid selector by a valid one.
25 * The only selector where it is allowed to do "mov ax,40;mov es,ax"
26 * is the so called 'bimodal' selector 0x40, which points to the BIOS
27 * data segment. Used by (at least) Borland products (and programs compiled
28 * using Borland products).
30 * See Undocumented Windows, Chapter 5, __0040.
32 static WORD
INSTR_ReplaceSelector( SIGCONTEXT
*context
, WORD sel
)
36 static WORD sys_timer
= 0;
38 sys_timer
= CreateSystemTimer( 55, (FARPROC16
)DOSMEM_Tick
);
39 return DOSMEM_BiosSeg
;
41 return 0; /* Can't replace selector, crashdump */
45 /***********************************************************************
46 * INSTR_GetOperandAddr
48 * Return the address of an instruction operand (from the mod/rm byte).
50 static BYTE
*INSTR_GetOperandAddr( SIGCONTEXT
*context
, BYTE
*instr
,
51 int long_addr
, int segprefix
, int *len
)
53 int mod
, rm
, base
, index
= 0, ss
= 0, seg
= 0, off
;
55 #define GET_VAL(val,type) \
56 { *val = *(type *)instr; instr += sizeof(type); *len += sizeof(type); }
59 GET_VAL( &mod
, BYTE
);
67 case 0: return (BYTE
*)&EAX_sig(context
);
68 case 1: return (BYTE
*)&ECX_sig(context
);
69 case 2: return (BYTE
*)&EDX_sig(context
);
70 case 3: return (BYTE
*)&EBX_sig(context
);
71 case 4: return (BYTE
*)&ESP_sig(context
);
72 case 5: return (BYTE
*)&EBP_sig(context
);
73 case 6: return (BYTE
*)&ESI_sig(context
);
74 case 7: return (BYTE
*)&EDI_sig(context
);
83 GET_VAL( &sib
, BYTE
);
88 case 0: index
= EAX_sig(context
); break;
89 case 1: index
= ECX_sig(context
); break;
90 case 2: index
= EDX_sig(context
); break;
91 case 3: index
= EBX_sig(context
); break;
92 case 4: index
= 0; break;
93 case 5: index
= EBP_sig(context
); break;
94 case 6: index
= ESI_sig(context
); break;
95 case 7: index
= EDI_sig(context
); break;
101 case 0: base
= EAX_sig(context
); seg
= DS_sig(context
); break;
102 case 1: base
= ECX_sig(context
); seg
= DS_sig(context
); break;
103 case 2: base
= EDX_sig(context
); seg
= DS_sig(context
); break;
104 case 3: base
= EBX_sig(context
); seg
= DS_sig(context
); break;
105 case 4: base
= ESP_sig(context
); seg
= SS_sig(context
); break;
106 case 5: base
= EBP_sig(context
); seg
= SS_sig(context
); break;
107 case 6: base
= ESI_sig(context
); seg
= DS_sig(context
); break;
108 case 7: base
= EDI_sig(context
); seg
= DS_sig(context
); break;
113 if (rm
== 5) /* special case: ds:(disp32) */
115 GET_VAL( &base
, DWORD
);
116 seg
= DS_sig(context
);
120 case 1: /* 8-bit disp */
121 GET_VAL( &off
, BYTE
);
122 base
+= (signed char)off
;
125 case 2: /* 32-bit disp */
126 GET_VAL( &off
, DWORD
);
127 base
+= (signed long)off
;
131 else /* short address */
135 case 0: /* ds:(bx,si) */
136 base
= BX_sig(context
) + SI_sig(context
);
137 seg
= DS_sig(context
);
139 case 1: /* ds:(bx,di) */
140 base
= BX_sig(context
) + DI_sig(context
);
141 seg
= DS_sig(context
);
143 case 2: /* ss:(bp,si) */
144 base
= BP_sig(context
) + SI_sig(context
);
145 seg
= SS_sig(context
);
147 case 3: /* ss:(bp,di) */
148 base
= BP_sig(context
) + DI_sig(context
);
149 seg
= SS_sig(context
);
151 case 4: /* ds:(si) */
152 base
= SI_sig(context
);
153 seg
= DS_sig(context
);
155 case 5: /* ds:(di) */
156 base
= DI_sig(context
);
157 seg
= DS_sig(context
);
159 case 6: /* ss:(bp) */
160 base
= BP_sig(context
);
161 seg
= SS_sig(context
);
163 case 7: /* ds:(bx) */
164 base
= BX_sig(context
);
165 seg
= DS_sig(context
);
172 if (rm
== 6) /* special case: ds:(disp16) */
174 GET_VAL( &base
, WORD
);
175 seg
= DS_sig(context
);
179 case 1: /* 8-bit disp */
180 GET_VAL( &off
, BYTE
);
181 base
+= (signed char)off
;
184 case 2: /* 16-bit disp */
185 GET_VAL( &off
, WORD
);
186 base
+= (signed short)off
;
191 if (segprefix
!= -1) seg
= segprefix
;
193 /* Make sure the segment and offset are valid */
194 if (((seg
& 7) != 7) || IS_SELECTOR_FREE(seg
)) return NULL
;
195 if (GET_SEL_LIMIT(seg
) < (base
+ (index
<< ss
))) return NULL
;
196 return (BYTE
*)PTR_SEG_OFF_TO_LIN( seg
, (base
+ (index
<< ss
)) );
201 /***********************************************************************
204 * Emulate the LDS (and LES,LFS,etc.) instruction.
206 static BOOL32
INSTR_EmulateLDS( SIGCONTEXT
*context
, BYTE
*instr
, int long_op
,
207 int long_addr
, int segprefix
, int *len
)
210 BYTE
*regmodrm
= instr
+ 1 + (*instr
== 0x0f);
211 BYTE
*addr
= INSTR_GetOperandAddr( context
, regmodrm
,
212 long_addr
, segprefix
, len
);
214 return FALSE
; /* Unable to emulate it */
215 seg
= *(WORD
*)(addr
+ (long_op
? 4 : 2));
217 if (!(seg
= INSTR_ReplaceSelector( context
, seg
)))
218 return FALSE
; /* Unable to emulate it */
220 /* Now store the offset in the correct register */
222 switch((*regmodrm
>> 3) & 7)
225 if (long_op
) EAX_sig(context
) = *(DWORD
*)addr
;
226 else AX_sig(context
) = *(WORD
*)addr
;
229 if (long_op
) ECX_sig(context
) = *(DWORD
*)addr
;
230 else CX_sig(context
) = *(WORD
*)addr
;
233 if (long_op
) EDX_sig(context
) = *(DWORD
*)addr
;
234 else DX_sig(context
) = *(WORD
*)addr
;
237 if (long_op
) EBX_sig(context
) = *(DWORD
*)addr
;
238 else BX_sig(context
) = *(WORD
*)addr
;
241 if (long_op
) ESP_sig(context
) = *(DWORD
*)addr
;
242 else SP_sig(context
) = *(WORD
*)addr
;
245 if (long_op
) EBP_sig(context
) = *(DWORD
*)addr
;
246 else BP_sig(context
) = *(WORD
*)addr
;
249 if (long_op
) ESI_sig(context
) = *(DWORD
*)addr
;
250 else SI_sig(context
) = *(WORD
*)addr
;
253 if (long_op
) EDI_sig(context
) = *(DWORD
*)addr
;
254 else DI_sig(context
) = *(WORD
*)addr
;
258 /* Store the correct segment in the segment register */
262 case 0xc4: ES_sig(context
) = seg
; break; /* les */
263 case 0xc5: DS_sig(context
) = seg
; break; /* lds */
264 case 0x0f: switch(instr
[1])
266 case 0xb2: SS_sig(context
) = seg
; break; /* lss */
268 case 0xb4: FS_sig(context
) = seg
; break; /* lfs */
271 case 0xb5: GS_sig(context
) = seg
; break; /* lgs */
277 /* Add the opcode size to the total length */
279 *len
+= 1 + (*instr
== 0x0f);
284 /***********************************************************************
285 * INSTR_EmulateInstruction
287 * Emulate a priviledged instruction. Returns TRUE if emulation successful.
289 BOOL32
INSTR_EmulateInstruction( SIGCONTEXT
*context
)
291 int prefix
, segprefix
, prefixlen
, len
, repX
, long_op
, long_addr
;
294 long_op
= long_addr
= (GET_SEL_FLAGS(CS_sig(context
)) & LDT_FLAGS_32BIT
) != 0;
295 instr
= (BYTE
*) PTR_SEG_OFF_TO_LIN( CS_sig(context
), EIP_sig(context
) );
297 /* First handle any possible prefix */
299 segprefix
= -1; /* no prefix */
308 segprefix
= CS_sig(context
);
311 segprefix
= SS_sig(context
);
314 segprefix
= DS_sig(context
);
317 segprefix
= ES_sig(context
);
321 segprefix
= FS_sig(context
);
326 segprefix
= GS_sig(context
);
330 long_op
= !long_op
; /* opcode size prefix */
333 long_addr
= !long_addr
; /* addr size prefix */
335 case 0xf0: /* lock */
337 case 0xf2: /* repne */
340 case 0xf3: /* repe */
344 prefix
= 0; /* no more prefixes */
354 /* Now look at the actual instruction */
358 case 0x07: /* pop es */
359 case 0x17: /* pop ss */
360 case 0x1f: /* pop ds */
362 WORD seg
= *(WORD
*)STACK_PTR( context
);
363 if ((seg
= INSTR_ReplaceSelector( context
, seg
)) != 0)
367 case 0x07: ES_sig(context
) = seg
; break;
368 case 0x17: SS_sig(context
) = seg
; break;
369 case 0x1f: DS_sig(context
) = seg
; break;
371 STACK_sig(context
) += long_op
? 4 : 2;
372 EIP_sig(context
) += prefixlen
+ 1;
376 break; /* Unable to emulate it */
378 case 0x0f: /* extended instruction */
382 case 0xa1: /* pop fs */
384 WORD seg
= *(WORD
*)STACK_PTR( context
);
385 if ((seg
= INSTR_ReplaceSelector( context
, seg
)) != 0)
387 FS_sig(context
) = seg
;
388 STACK_sig(context
) += long_op
? 4 : 2;
389 EIP_sig(context
) += prefixlen
+ 2;
397 case 0xa9: /* pop gs */
399 WORD seg
= *(WORD
*)STACK_PTR( context
);
400 if ((seg
= INSTR_ReplaceSelector( context
, seg
)) != 0)
402 GS_sig(context
) = seg
;
403 STACK_sig(context
) += long_op
? 4 : 2;
404 EIP_sig(context
) += prefixlen
+ 2;
411 case 0xb2: /* lss addr,reg */
413 case 0xb4: /* lfs addr,reg */
416 case 0xb5: /* lgs addr,reg */
418 if (INSTR_EmulateLDS( context
, instr
, long_op
,
419 long_addr
, segprefix
, &len
))
421 EIP_sig(context
) += prefixlen
+ len
;
426 break; /* Unable to emulate it */
428 case 0x6c: /* insb */
429 case 0x6d: /* insw/d */
430 case 0x6e: /* outsb */
431 case 0x6f: /* outsw/d */
433 int typ
= *instr
; /* Just in case it's overwritten. */
434 int outp
= (typ
>= 0x6e);
435 unsigned long count
= repX
?
436 (long_addr
? ECX_sig(context
) : CX_sig(context
)) : 1;
437 int opsize
= (typ
& 1) ? (long_op
? 4 : 2) : 1;
438 int step
= (EFL_sig(context
) & 0x400) ? -opsize
: +opsize
;
439 int seg
= outp
? DS_sig(context
) : ES_sig(context
); /* FIXME: is this right? */
442 /* FIXME: Check segment readable. */
445 /* FIXME: Check segment writeable. */
450 ECX_sig(context
) = 0;
459 data
= PTR_SEG_OFF_TO_LIN (seg
,
460 long_addr
? ESI_sig(context
) : SI_sig(context
));
461 if (long_addr
) ESI_sig(context
) += step
;
462 else SI_sig(context
) += step
;
466 data
= PTR_SEG_OFF_TO_LIN (seg
,
467 long_addr
? EDI_sig(context
) : DI_sig(context
));
468 if (long_addr
) EDI_sig(context
) += step
;
469 else DI_sig(context
) += step
;
475 *((BYTE
*)data
) = IO_inport( DX_sig(context
), 1);
479 *((DWORD
*)data
) = IO_inport( DX_sig(context
), 4);
481 *((WORD
*)data
) = IO_inport( DX_sig(context
), 2);
484 IO_outport( DX_sig(context
), 1, *((BYTE
*)data
));
488 IO_outport( DX_sig(context
), 4, *((DWORD
*)data
));
490 IO_outport( DX_sig(context
), 2, *((WORD
*)data
));
494 EIP_sig(context
) += prefixlen
+ 1;
498 case 0x8e: /* mov XX,segment_reg */
501 BYTE
*addr
= INSTR_GetOperandAddr(context
, instr
+ 1,
502 long_addr
, segprefix
, &len
);
504 break; /* Unable to emulate it */
506 if (!(seg
= INSTR_ReplaceSelector( context
, seg
)))
507 break; /* Unable to emulate it */
509 switch((instr
[1] >> 3) & 7)
512 ES_sig(context
) = seg
;
513 EIP_sig(context
) += prefixlen
+ len
+ 1;
518 SS_sig(context
) = seg
;
519 EIP_sig(context
) += prefixlen
+ len
+ 1;
522 DS_sig(context
) = seg
;
523 EIP_sig(context
) += prefixlen
+ len
+ 1;
527 FS_sig(context
) = seg
;
528 EIP_sig(context
) += prefixlen
+ len
+ 1;
533 GS_sig(context
) = seg
;
534 EIP_sig(context
) += prefixlen
+ len
+ 1;
542 break; /* Unable to emulate it */
544 case 0xc4: /* les addr,reg */
545 case 0xc5: /* lds addr,reg */
546 if (INSTR_EmulateLDS( context
, instr
, long_op
,
547 long_addr
, segprefix
, &len
))
549 EIP_sig(context
) += prefixlen
+ len
;
552 break; /* Unable to emulate it */
554 case 0xcd: /* int <XX> */
557 fprintf(stderr
, "int xx from 32-bit code is not supported.\n");
558 break; /* Unable to emulate it */
562 FARPROC16 addr
= INT_GetHandler( instr
[1] );
563 WORD
*stack
= (WORD
*)STACK_PTR( context
);
564 /* Push the flags and return address on the stack */
565 *(--stack
) = FL_sig(context
);
566 *(--stack
) = CS_sig(context
);
567 *(--stack
) = IP_sig(context
) + prefixlen
+ 2;
568 STACK_sig(context
) -= 3 * sizeof(WORD
);
569 /* Jump to the interrupt handler */
570 CS_sig(context
) = HIWORD(addr
);
571 EIP_sig(context
) = LOWORD(addr
);
575 case 0xcf: /* iret */
578 DWORD
*stack
= (DWORD
*)STACK_PTR( context
);
579 EIP_sig(context
) = *stack
++;
580 CS_sig(context
) = *stack
++;
581 EFL_sig(context
) = *stack
;
582 STACK_sig(context
) += 3*sizeof(DWORD
); /* Pop the return address and flags */
586 WORD
*stack
= (WORD
*)STACK_PTR( context
);
587 EIP_sig(context
) = *stack
++;
588 CS_sig(context
) = *stack
++;
589 FL_sig(context
) = *stack
;
590 STACK_sig(context
) += 3*sizeof(WORD
); /* Pop the return address and flags */
594 case 0xe4: /* inb al,XX */
595 AL_sig(context
) = IO_inport( instr
[1], 1 );
596 EIP_sig(context
) += prefixlen
+ 2;
599 case 0xe5: /* in (e)ax,XX */
600 if (long_op
) EAX_sig(context
) = IO_inport( instr
[1], 4 );
601 else AX_sig(context
) = IO_inport( instr
[1], 2 );
602 EIP_sig(context
) += prefixlen
+ 2;
605 case 0xe6: /* outb XX,al */
606 IO_outport( instr
[1], 1, AL_sig(context
) );
607 EIP_sig(context
) += prefixlen
+ 2;
610 case 0xe7: /* out XX,(e)ax */
611 if (long_op
) IO_outport( instr
[1], 4, EAX_sig(context
) );
612 else IO_outport( instr
[1], 2, AX_sig(context
) );
613 EIP_sig(context
) += prefixlen
+ 2;
616 case 0xec: /* inb al,dx */
617 AL_sig(context
) = IO_inport( DX_sig(context
), 1 );
618 EIP_sig(context
) += prefixlen
+ 1;
621 case 0xed: /* in (e)ax,dx */
622 if (long_op
) EAX_sig(context
) = IO_inport( DX_sig(context
), 4 );
623 else AX_sig(context
) = IO_inport( DX_sig(context
), 2 );
624 EIP_sig(context
) += prefixlen
+ 1;
627 case 0xee: /* outb dx,al */
628 IO_outport( DX_sig(context
), 1, AL_sig(context
) );
629 EIP_sig(context
) += prefixlen
+ 1;
632 case 0xef: /* out dx,(e)ax */
633 if (long_op
) IO_outport( DX_sig(context
), 4, EAX_sig(context
) );
634 else IO_outport( DX_sig(context
), 2, AX_sig(context
) );
635 EIP_sig(context
) += prefixlen
+ 1;
638 case 0xfa: /* cli, ignored */
639 EIP_sig(context
) += prefixlen
+ 1;
642 case 0xfb: /* sti, ignored */
643 EIP_sig(context
) += prefixlen
+ 1;
646 fprintf(stderr
, "Unexpected Windows program segfault"
647 " - opcode = %x\n", *instr
);
648 return FALSE
; /* Unable to emulate it */