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 sprintf(M.x86.decoded_buf+M.x86.enc_str_pos,"%s",x);
167 M.x86.enc_str_pos += strlen(x);
170 void x86emu_decode_printf2 (const char *x, int y)
174 sprintf(M.x86.decoded_buf+M.x86.enc_str_pos,"%s",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 sprintf(buf1+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;
217 while (end <= off + amt) {
218 printf("%04x:%04x ", seg, start);
219 for (i=start; i< off; i++)
222 printf("%02x ", fetch_data_byte_abs(seg,i));
229 void x86emu_single_step (void)
239 static int breakpoint;
240 static int noDecode = 1;
245 if (M.x86.saved_ip != breakpoint) {
248 M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
249 M.x86.debug |= DEBUG_TRACE_F;
250 M.x86.debug &= ~DEBUG_BREAK_F;
251 print_decoded_instruction ();
256 offset = M.x86.saved_ip;
259 p = fgets(s, 1023, stdin);
260 cmd = parse_line(s, ps, &ntok);
263 disassemble_forward(M.x86.saved_cs,(u16)offset,10);
267 segment = M.x86.saved_cs;
269 X86EMU_dump_memory(segment,(u16)offset,16);
271 } else if (ntok == 3) {
274 X86EMU_dump_memory(segment,(u16)offset,16);
277 segment = M.x86.saved_cs;
278 X86EMU_dump_memory(segment,(u16)offset,16);
283 M.x86.debug ^= DEBUG_TRACECALL_F;
286 M.x86.debug ^= DEBUG_SVC_F | DEBUG_SYS_F | DEBUG_SYSINT_F;
292 X86EMU_trace_xregs();
298 M.x86.debug |= DEBUG_DECODE_NOPRINT_F;
300 M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
302 M.x86.debug &= ~DEBUG_TRACE_F;
303 M.x86.debug |= DEBUG_BREAK_F;
308 M.x86.debug |= DEBUG_EXIT;
311 noDecode = (noDecode)?0:1;
312 printf("Toggled decoding to %s\n",(noDecode)?"FALSE":"TRUE");
323 int X86EMU_trace_on(void)
325 return M.x86.debug |= DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F;
328 int X86EMU_trace_off(void)
330 return M.x86.debug &= ~(DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F);
333 int parse_line (char *s, int *ps, int *n)
339 while(*s == ' ' || *s == '\t') s++;
351 while (*s != ' ' && *s != '\t' && *s != '\n') s++;
356 while(*s == ' ' || *s == '\t') s++;
358 sscanf(s,"%x",&ps[*n]);
368 void x86emu_dump_regs (void)
370 printf("\tAX=%04x ", M.x86.R_AX );
371 printf("BX=%04x ", M.x86.R_BX );
372 printf("CX=%04x ", M.x86.R_CX );
373 printf("DX=%04x ", M.x86.R_DX );
374 printf("SP=%04x ", M.x86.R_SP );
375 printf("BP=%04x ", M.x86.R_BP );
376 printf("SI=%04x ", M.x86.R_SI );
377 printf("DI=%04x\n", M.x86.R_DI );
378 printf("\tDS=%04x ", M.x86.R_DS );
379 printf("ES=%04x ", M.x86.R_ES );
380 printf("SS=%04x ", M.x86.R_SS );
381 printf("CS=%04x ", M.x86.R_CS );
382 printf("IP=%04x ", M.x86.R_IP );
383 if (ACCESS_FLAG(F_OF)) printf("OV "); /* CHECKED... */
385 if (ACCESS_FLAG(F_DF)) printf("DN ");
387 if (ACCESS_FLAG(F_IF)) printf("EI ");
389 if (ACCESS_FLAG(F_SF)) printf("NG ");
391 if (ACCESS_FLAG(F_ZF)) printf("ZR ");
393 if (ACCESS_FLAG(F_AF)) printf("AC ");
395 if (ACCESS_FLAG(F_PF)) printf("PE ");
397 if (ACCESS_FLAG(F_CF)) printf("CY ");
402 void x86emu_dump_xregs (void)
404 printf("\tEAX=%08x ", M.x86.R_EAX );
405 printf("EBX=%08x ", M.x86.R_EBX );
406 printf("ECX=%08x ", M.x86.R_ECX );
407 printf("EDX=%08x \n", M.x86.R_EDX );
408 printf("\tESP=%08x ", M.x86.R_ESP );
409 printf("EBP=%08x ", M.x86.R_EBP );
410 printf("ESI=%08x ", M.x86.R_ESI );
411 printf("EDI=%08x\n", M.x86.R_EDI );
412 printf("\tDS=%04x ", M.x86.R_DS );
413 printf("ES=%04x ", M.x86.R_ES );
414 printf("SS=%04x ", M.x86.R_SS );
415 printf("CS=%04x ", M.x86.R_CS );
416 printf("EIP=%08x\n\t", M.x86.R_EIP );
417 if (ACCESS_FLAG(F_OF)) printf("OV "); /* CHECKED... */
419 if (ACCESS_FLAG(F_DF)) printf("DN ");
421 if (ACCESS_FLAG(F_IF)) printf("EI ");
423 if (ACCESS_FLAG(F_SF)) printf("NG ");
425 if (ACCESS_FLAG(F_ZF)) printf("ZR ");
427 if (ACCESS_FLAG(F_AF)) printf("AC ");
429 if (ACCESS_FLAG(F_PF)) printf("PE ");
431 if (ACCESS_FLAG(F_CF)) printf("CY ");