1 /****************************************************************************
3 * Realmode X86 Emulator Library
5 * Copyright (C) 1991-2004 SciTech Software, Inc.
6 * Copyright (C) David Mosberger-Tang
7 * Copyright (C) 1999 Egbert Eich
9 * ========================================================================
11 * Permission to use, copy, modify, distribute, and sell this software and
12 * its documentation for any purpose is hereby granted without fee,
13 * provided that the above copyright notice appear in all copies and that
14 * both that copyright notice and this permission notice appear in
15 * supporting documentation, and that the name of the authors not be used
16 * in advertising or publicity pertaining to distribution of the software
17 * without specific, written prior permission. The authors makes no
18 * representations about the suitability of this software for any purpose.
19 * It is provided "as is" without express or implied warranty.
21 * THE AUTHORS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
22 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
23 * EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
24 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
25 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
26 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
27 * PERFORMANCE OF THIS SOFTWARE.
29 * ========================================================================
33 * Developer: Kendall Bennett
35 * Description: This file contains the code to handle debugging of the
38 ****************************************************************************/
42 /*----------------------------- Implementation ----------------------------*/
46 static void print_encoded_bytes (u16 s
, u16 o
);
47 static void print_decoded_instruction (void);
48 int parse_line (char *s
, int *ps
, int *n
);
50 /* should look something like debug's output. */
51 void X86EMU_trace_regs (void)
54 if (M
.x86
.mode
& (SYSMODE_PREFIX_DATA
| SYSMODE_PREFIX_ADDR
)) {
60 if (DEBUG_DECODE() && ! DEBUG_DECODE_NOPRINT()) {
61 printf("%04x:%04x ",M
.x86
.saved_cs
, M
.x86
.saved_ip
);
62 print_encoded_bytes( M
.x86
.saved_cs
, M
.x86
.saved_ip
);
63 print_decoded_instruction();
67 void X86EMU_trace_xregs (void)
74 void x86emu_just_disassemble (void)
77 * This routine called if the flag DEBUG_DISASSEMBLE is set kind
80 printf("%04x:%04x ",M
.x86
.saved_cs
, M
.x86
.saved_ip
);
81 print_encoded_bytes( M
.x86
.saved_cs
, M
.x86
.saved_ip
);
82 print_decoded_instruction();
85 void disassemble_forward (u16 seg
, u16 off
, int n
)
91 * hack, hack, hack. What we do is use the exact machinery set up
92 * for execution, except that now there is an additional state
93 * flag associated with the "execution", and we are using a copy
94 * of the register struct. All the major opcodes, once fully
95 * decoded, have the following two steps: TRACE_REGS(r,m);
96 * SINGLE_STEP(r,m); which disappear if DEBUG is not defined to
97 * the preprocessor. The TRACE_REGS macro expands to:
99 * if (debug&DEBUG_DISASSEMBLE)
100 * {just_disassemble(); goto EndOfInstruction;}
101 * if (debug&DEBUG_TRACE) trace_regs(r,m);
103 * ...... and at the last line of the routine.
105 * EndOfInstruction: end_instr();
107 * Up to the point where TRACE_REG is expanded, NO modifications
108 * are done to any register EXCEPT the IP register, for fetch and
111 * This was done for an entirely different reason, but makes a
112 * nice way to get the system to help debug codes.
115 tregs
.x86
.R_IP
= off
;
116 tregs
.x86
.R_CS
= seg
;
118 /* reset the decoding buffers */
119 tregs
.x86
.enc_str_pos
= 0;
120 tregs
.x86
.enc_pos
= 0;
122 /* turn on the "disassemble only, no execute" flag */
123 tregs
.x86
.debug
|= DEBUG_DISASSEMBLE_F
;
125 /* DUMP NEXT n instructions to screen in straight_line fashion */
127 * This looks like the regular instruction fetch stream, except
128 * that when this occurs, each fetched opcode, upon seeing the
129 * DEBUG_DISASSEMBLE flag set, exits immediately after decoding
130 * the instruction. XXX --- CHECK THAT MEM IS NOT AFFECTED!!!
131 * Note the use of a copy of the register structure...
133 for (i
=0; i
<n
; i
++) {
134 op1
= (*sys_rdb
)(((u32
)M
.x86
.R_CS
<<4) + (M
.x86
.R_IP
++));
135 (x86emu_optab
[op1
])(op1
);
137 /* end major hack mode. */
140 void x86emu_check_ip_access (void)
145 void x86emu_check_sp_access (void)
149 void x86emu_check_mem_access (u32 dummy
)
151 /* check bounds, etc */
154 void x86emu_check_data_access (uint dummy1
, uint dummy2
)
156 /* check bounds, etc */
159 void x86emu_inc_decoded_inst_len (int x
)
164 void x86emu_decode_printf (const char *x
)
166 strcpy(M
.x86
.decoded_buf
+M
.x86
.enc_str_pos
,x
);
167 M
.x86
.enc_str_pos
+= strlen(x
);
170 void x86emu_decode_printf2 (const char *x
, int y
)
173 snprintf(temp
, sizeof(temp
), x
,y
);
174 strcpy(M
.x86
.decoded_buf
+M
.x86
.enc_str_pos
,temp
);
175 M
.x86
.enc_str_pos
+= strlen(temp
);
178 void x86emu_end_instr (void)
180 M
.x86
.enc_str_pos
= 0;
184 static void print_encoded_bytes (u16 s
, u16 o
)
188 for (i
=0; i
< M
.x86
.enc_pos
; i
++) {
189 snprintf(buf1
+2*i
, 64 - 2 * i
, "%02x", fetch_data_byte_abs(s
,o
+i
));
191 printf("%-20s ",buf1
);
194 static void print_decoded_instruction (void)
196 printf("%s", M
.x86
.decoded_buf
);
199 void x86emu_print_int_vect (u16 iv
)
203 if (iv
> 256) return;
204 seg
= fetch_data_word_abs(0,iv
*4);
205 off
= fetch_data_word_abs(0,iv
*4+2);
206 printf("%04x:%04x ", seg
, off
);
209 void X86EMU_dump_memory (u16 seg
, u16 off
, u32 amt
)
211 u32 start
= off
& 0xfffffff0;
212 u32 end
= (off
+16) & 0xfffffff0;
215 while (end
<= off
+ amt
) {
216 printf("%04x:%04x ", seg
, start
);
217 for (i
=start
; i
< off
; i
++)
220 printf("%02x ", fetch_data_byte_abs(seg
,i
));
227 void x86emu_single_step (void)
237 static int breakpoint
;
238 static int noDecode
= 1;
241 if (M
.x86
.saved_ip
!= breakpoint
) {
244 M
.x86
.debug
&= ~DEBUG_DECODE_NOPRINT_F
;
245 M
.x86
.debug
|= DEBUG_TRACE_F
;
246 M
.x86
.debug
&= ~DEBUG_BREAK_F
;
247 print_decoded_instruction ();
252 offset
= M
.x86
.saved_ip
;
255 (void)fgets(s
, 1023, stdin
);
256 cmd
= parse_line(s
, ps
, &ntok
);
259 disassemble_forward(M
.x86
.saved_cs
,(u16
)offset
,10);
263 segment
= M
.x86
.saved_cs
;
265 X86EMU_dump_memory(segment
,(u16
)offset
,16);
267 } else if (ntok
== 3) {
270 X86EMU_dump_memory(segment
,(u16
)offset
,16);
273 segment
= M
.x86
.saved_cs
;
274 X86EMU_dump_memory(segment
,(u16
)offset
,16);
279 M
.x86
.debug
^= DEBUG_TRACECALL_F
;
282 M
.x86
.debug
^= DEBUG_SVC_F
| DEBUG_SYS_F
| DEBUG_SYSINT_F
;
288 X86EMU_trace_xregs();
294 M
.x86
.debug
|= DEBUG_DECODE_NOPRINT_F
;
296 M
.x86
.debug
&= ~DEBUG_DECODE_NOPRINT_F
;
298 M
.x86
.debug
&= ~DEBUG_TRACE_F
;
299 M
.x86
.debug
|= DEBUG_BREAK_F
;
304 M
.x86
.debug
|= DEBUG_EXIT
;
307 noDecode
= (noDecode
)?0:1;
308 printf("Toggled decoding to %s\n",(noDecode
)?"FALSE":"TRUE");
319 int X86EMU_trace_on(void)
321 return M
.x86
.debug
|= DEBUG_STEP_F
| DEBUG_DECODE_F
| DEBUG_TRACE_F
;
324 int X86EMU_trace_off(void)
326 return M
.x86
.debug
&= ~(DEBUG_STEP_F
| DEBUG_DECODE_F
| DEBUG_TRACE_F
);
329 int parse_line (char *s
, int *ps
, int *n
)
335 while(*s
== ' ' || *s
== '\t') s
++;
347 while (*s
!= ' ' && *s
!= '\t' && *s
!= '\n') s
++;
352 while(*s
== ' ' || *s
== '\t') s
++;
354 sscanf(s
,"%x",&ps
[*n
]);
364 void x86emu_dump_regs (void)
366 printf("\tAX=%04x ", M
.x86
.R_AX
);
367 printf("BX=%04x ", M
.x86
.R_BX
);
368 printf("CX=%04x ", M
.x86
.R_CX
);
369 printf("DX=%04x ", M
.x86
.R_DX
);
370 printf("SP=%04x ", M
.x86
.R_SP
);
371 printf("BP=%04x ", M
.x86
.R_BP
);
372 printf("SI=%04x ", M
.x86
.R_SI
);
373 printf("DI=%04x\n", M
.x86
.R_DI
);
374 printf("\tDS=%04x ", M
.x86
.R_DS
);
375 printf("ES=%04x ", M
.x86
.R_ES
);
376 printf("SS=%04x ", M
.x86
.R_SS
);
377 printf("CS=%04x ", M
.x86
.R_CS
);
378 printf("IP=%04x ", M
.x86
.R_IP
);
379 if (ACCESS_FLAG(F_OF
)) printf("OV "); /* CHECKED... */
381 if (ACCESS_FLAG(F_DF
)) printf("DN ");
383 if (ACCESS_FLAG(F_IF
)) printf("EI ");
385 if (ACCESS_FLAG(F_SF
)) printf("NG ");
387 if (ACCESS_FLAG(F_ZF
)) printf("ZR ");
389 if (ACCESS_FLAG(F_AF
)) printf("AC ");
391 if (ACCESS_FLAG(F_PF
)) printf("PE ");
393 if (ACCESS_FLAG(F_CF
)) printf("CY ");
398 void x86emu_dump_xregs (void)
400 printf("\tEAX=%08x ", M
.x86
.R_EAX
);
401 printf("EBX=%08x ", M
.x86
.R_EBX
);
402 printf("ECX=%08x ", M
.x86
.R_ECX
);
403 printf("EDX=%08x\n", M
.x86
.R_EDX
);
404 printf("\tESP=%08x ", M
.x86
.R_ESP
);
405 printf("EBP=%08x ", M
.x86
.R_EBP
);
406 printf("ESI=%08x ", M
.x86
.R_ESI
);
407 printf("EDI=%08x\n", M
.x86
.R_EDI
);
408 printf("\tDS=%04x ", M
.x86
.R_DS
);
409 printf("ES=%04x ", M
.x86
.R_ES
);
410 printf("SS=%04x ", M
.x86
.R_SS
);
411 printf("CS=%04x ", M
.x86
.R_CS
);
412 printf("EIP=%08x\n\t", M
.x86
.R_EIP
);
413 if (ACCESS_FLAG(F_OF
)) printf("OV "); /* CHECKED... */
415 if (ACCESS_FLAG(F_DF
)) printf("DN ");
417 if (ACCESS_FLAG(F_IF
)) printf("EI ");
419 if (ACCESS_FLAG(F_SF
)) printf("NG ");
421 if (ACCESS_FLAG(F_ZF
)) printf("ZR ");
423 if (ACCESS_FLAG(F_AF
)) printf("AC ");
425 if (ACCESS_FLAG(F_PF
)) printf("PE ");
427 if (ACCESS_FLAG(F_CF
)) printf("CY ");