libs/x86emu/debug.c

   1 /****************************************************************************
   2 *
   3 *                                               Realmode X86 Emulator Library
   4 *
   5 *               Copyright (C) 1996-1999 SciTech Software, Inc.
   6 *                                    Copyright (C) David Mosberger-Tang
   7 *                                          Copyright (C) 1999 Egbert Eich
   8 *
   9 *  ========================================================================
  10 *
  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.
  20 *
  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.
  28 *
  29 *  ========================================================================
  30 *
  31 * Language:             ANSI C
  32 * Environment:  Any
  33 * Developer:    Kendall Bennett
  34 *
  35 * Description:  This file contains the code to handle debugging of the
  36 *                               emulator.
  37 *
  38 ****************************************************************************/
  39
  40 #include "x86emu/x86emui.h"
  41 #ifndef NO_SYS_HEADERS
  42 #include <stdarg.h>
  43 #include <stdlib.h>
  44 #endif
  45
  46 /*----------------------------- Implementation ----------------------------*/
  47
  48 #ifdef DEBUG
  49
  50 static void     print_encoded_bytes (u16 s, u16 o);
  51 static void     print_decoded_instruction (void);
  52 static int      parse_line (char *s, int *ps, int *n);
  53
  54 /* should look something like debug's output. */
  55 void X86EMU_trace_regs (void)
  56 {
  57         if (DEBUG_TRACE()) {
  58                 x86emu_dump_regs();
  59     }
  60         if (DEBUG_DECODE() && ! DEBUG_DECODE_NOPRINT()) {
  61                 printk("%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();
  64     }
  65 }
  66
  67 void X86EMU_trace_xregs (void)
  68 {
  69         if (DEBUG_TRACE()) {
  70                 x86emu_dump_xregs();
  71     }
  72 }
  73
  74 void x86emu_just_disassemble (void)
  75 {
  76     /*
  77      * This routine called if the flag DEBUG_DISASSEMBLE is set kind
  78      * of a hack!
  79      */
  80         printk("%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();
  83 }
  84
  85 static void disassemble_forward (u16 seg, u16 off, int n)
  86 {
  87         X86EMU_sysEnv tregs;
  88         int i;
  89         u8 op1;
  90     /*
  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:
  98      *
  99      * if (debug&DEBUG_DISASSEMBLE)
 100      *     {just_disassemble(); goto EndOfInstruction;}
 101      *     if (debug&DEBUG_TRACE) trace_regs(r,m);
 102      *
 103      * ......  and at the last line of the routine.
 104      *
 105      * EndOfInstruction: end_instr();
 106      *
 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
 109      * decoding purposes.
 110      *
 111      * This was done for an entirely different reason, but makes a
 112      * nice way to get the system to help debug codes.
 113      */
 114         tregs = M;
 115     tregs.x86.R_IP = off;
 116     tregs.x86.R_CS = seg;
 117
 118     /* reset the decoding buffers */
 119     tregs.x86.enc_str_pos = 0;
 120     tregs.x86.enc_pos = 0;
 121
 122     /* turn on the "disassemble only, no execute" flag */
 123     tregs.x86.debug |= DEBUG_DISASSEMBLE_F;
 124
 125     /* DUMP NEXT n instructions to screen in straight_line fashion */
 126     /*
 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...
 132      */
 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);
 136     }
 137     /* end major hack mode. */
 138 }
 139
 140 void x86emu_check_ip_access (void)
 141 {
 142     /* NULL as of now */
 143 }
 144
 145 void x86emu_check_sp_access (void)
 146 {
 147 }
 148
 149 void x86emu_check_mem_access (u32 dummy)
 150 {
 151         /*  check bounds, etc */
 152 }
 153
 154 void x86emu_check_data_access (uint dummy1, uint dummy2)
 155 {
 156         /*  check bounds, etc */
 157 }
 158
 159 void x86emu_inc_decoded_inst_len (int x)
 160 {
 161         M.x86.enc_pos += x;
 162 }
 163
 164 void x86emu_decode_printf (char *x)
 165 {
 166         sprintf(M.x86.decoded_buf+M.x86.enc_str_pos,"%s",x);
 167         M.x86.enc_str_pos += strlen(x);
 168 }
 169
 170 void x86emu_decode_printf2 (char *x, int y)
 171 {
 172         char temp[100];
 173         sprintf(temp,x,y);
 174         sprintf(M.x86.decoded_buf+M.x86.enc_str_pos,"%s",temp);
 175         M.x86.enc_str_pos += strlen(temp);
 176 }
 177
 178 void x86emu_end_instr (void)
 179 {
 180         M.x86.enc_str_pos = 0;
 181         M.x86.enc_pos = 0;
 182 }
 183
 184 static void print_encoded_bytes (u16 s, u16 o)
 185 {
 186     int i;
 187     char buf1[64];
 188         for (i=0; i< M.x86.enc_pos; i++) {
 189                 sprintf(buf1+2*i,"%02x", fetch_data_byte_abs(s,o+i));
 190     }
 191         printk("%-20s",buf1);
 192 }
 193
 194 static void print_decoded_instruction (void)
 195 {
 196         printk("%s", M.x86.decoded_buf);
 197 }
 198
 199 void x86emu_print_int_vect (u16 iv)
 200 {
 201         u16 seg,off;
 202
 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         printk("%04x:%04x ", seg, off);
 207 }
 208
 209 void X86EMU_dump_memory (u16 seg, u16 off, u32 amt)
 210 {
 211         u32 start = off & 0xfffffff0;
 212         u32 end  = (off+16) & 0xfffffff0;
 213         u32 i;
 214         u32 current;
 215
 216         current = start;
 217         while (end <= off + amt) {
 218                 printk("%04x:%04x ", seg, start);
 219                 for (i=start; i< off; i++)
 220                   printk("   ");
 221                 for (       ; i< end; i++)
 222                   printk("%02x ", fetch_data_byte_abs(seg,i));
 223                 printk("\n");
 224                 start = end;
 225                 end = start + 16;
 226         }
 227 }
 228
 229 void x86emu_single_step (void)
 230 {
 231     char s[1024];
 232     int ps[10];
 233     int ntok;
 234     int cmd;
 235     int done;
 236                 int segment;
 237     int offset;
 238     static int breakpoint;
 239     static int noDecode = 1;
 240
 241     char *p;
 242
 243                 if (DEBUG_BREAK()) {
 244                                 if (M.x86.saved_ip != breakpoint) {
 245                                                 return;
 246                                 } else {
 247                   M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
 248                                                 M.x86.debug |= DEBUG_TRACE_F;
 249                                                 M.x86.debug &= ~DEBUG_BREAK_F;
 250                                                 print_decoded_instruction ();
 251                                                 X86EMU_trace_regs();
 252                                 }
 253                 }
 254     done=0;
 255         offset = M.x86.saved_ip;
 256     while (!done) {
 257         printk("-");
 258         p = fgets(s, 1023, stdin);
 259         cmd = parse_line(s, ps, &ntok);
 260         switch(cmd) {
 261           case 'u':
 262                         disassemble_forward(M.x86.saved_cs,(u16)offset,10);
 263             break;
 264           case 'd':
 265                                                         if (ntok == 2) {
 266                                                                         segment = M.x86.saved_cs;
 267                                                                         offset = ps[1];
 268                                                                         X86EMU_dump_memory(segment,(u16)offset,16);
 269                                                                         offset += 16;
 270                                                         } else if (ntok == 3) {
 271                                                                         segment = ps[1];
 272                                                                         offset = ps[2];
 273                                                                         X86EMU_dump_memory(segment,(u16)offset,16);
 274                                                                         offset += 16;
 275                                                         } else {
 276                                                                         segment = M.x86.saved_cs;
 277                                                                         X86EMU_dump_memory(segment,(u16)offset,16);
 278                                                                         offset += 16;
 279                                                         }
 280             break;
 281           case 'c':
 282                         M.x86.debug ^= DEBUG_TRACECALL_F;
 283             break;
 284           case 's':
 285                         M.x86.debug ^= DEBUG_SVC_F | DEBUG_SYS_F | DEBUG_SYSINT_F;
 286             break;
 287           case 'r':
 288                         X86EMU_trace_regs();
 289             break;
 290           case 'x':
 291                         X86EMU_trace_xregs();
 292             break;
 293           case 'g':
 294             if (ntok == 2) {
 295                 breakpoint = ps[1];
 296                 if (noDecode) {
 297                                 M.x86.debug |= DEBUG_DECODE_NOPRINT_F;
 298                 } else {
 299                                 M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
 300                 }
 301                 M.x86.debug &= ~DEBUG_TRACE_F;
 302                 M.x86.debug |= DEBUG_BREAK_F;
 303                 done = 1;
 304             }
 305             break;
 306           case 'q':
 307           M.x86.debug |= DEBUG_EXIT;
 308           return;
 309           case 'P':
 310               noDecode = (noDecode)?0:1;
 311               printk("Toggled decoding to %s\n",(noDecode)?"FALSE":"TRUE");
 312               break;
 313           case 't':
 314           case 0:
 315             done = 1;
 316             break;
 317         }
 318     }
 319 }
 320
 321 int X86EMU_trace_on(void)
 322 {
 323         return M.x86.debug |= DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F;
 324 }
 325
 326 int X86EMU_trace_off(void)
 327 {
 328         return M.x86.debug &= ~(DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F);
 329 }
 330
 331 static int parse_line (char *s, int *ps, int *n)
 332 {
 333     int cmd;
 334
 335     *n = 0;
 336     while(*s == ' ' || *s == '\t') s++;
 337     ps[*n] = *s;
 338     switch (*s) {
 339       case '\n':
 340         *n += 1;
 341         return 0;
 342       default:
 343         cmd = *s;
 344         *n += 1;
 345     }
 346
 347         while (1) {
 348                 while (*s != ' ' && *s != '\t' && *s != '\n')  s++;
 349
 350                 if (*s == '\n')
 351                         return cmd;
 352
 353                 while(*s == ' ' || *s == '\t') s++;
 354
 355                 sscanf(s,"%x",&ps[*n]);
 356                 *n += 1;
 357         }
 358 }
 359
 360 #endif /* DEBUG */
 361
 362 void x86emu_dump_regs (void)
 363 {
 364         printk("\tAX=%04x  ", M.x86.R_AX );
 365         printk("BX=%04x  ", M.x86.R_BX );
 366         printk("CX=%04x  ", M.x86.R_CX );
 367         printk("DX=%04x  ", M.x86.R_DX );
 368         printk("SP=%04x  ", M.x86.R_SP );
 369         printk("BP=%04x  ", M.x86.R_BP );
 370         printk("SI=%04x  ", M.x86.R_SI );
 371         printk("DI=%04x\n", M.x86.R_DI );
 372         printk("\tDS=%04x  ", M.x86.R_DS );
 373         printk("ES=%04x  ", M.x86.R_ES );
 374         printk("SS=%04x  ", M.x86.R_SS );
 375         printk("CS=%04x  ", M.x86.R_CS );
 376         printk("IP=%04x   ", M.x86.R_IP );
 377         if (ACCESS_FLAG(F_OF))    printk("OV ");     /* CHECKED... */
 378         else                        printk("NV ");
 379         if (ACCESS_FLAG(F_DF))    printk("DN ");
 380         else                        printk("UP ");
 381         if (ACCESS_FLAG(F_IF))    printk("EI ");
 382         else                        printk("DI ");
 383         if (ACCESS_FLAG(F_SF))    printk("NG ");
 384         else                        printk("PL ");
 385         if (ACCESS_FLAG(F_ZF))    printk("ZR ");
 386         else                        printk("NZ ");
 387         if (ACCESS_FLAG(F_AF))    printk("AC ");
 388         else                        printk("NA ");
 389         if (ACCESS_FLAG(F_PF))    printk("PE ");
 390         else                        printk("PO ");
 391         if (ACCESS_FLAG(F_CF))    printk("CY ");
 392         else                        printk("NC ");
 393         printk("\n");
 394 }
 395
 396 void x86emu_dump_xregs (void)
 397 {
 398         printk("\tEAX=%08x  ", M.x86.R_EAX );
 399         printk("EBX=%08x  ", M.x86.R_EBX );
 400         printk("ECX=%08x  ", M.x86.R_ECX );
 401         printk("EDX=%08x  \n", M.x86.R_EDX );
 402         printk("\tESP=%08x  ", M.x86.R_ESP );
 403         printk("EBP=%08x  ", M.x86.R_EBP );
 404         printk("ESI=%08x  ", M.x86.R_ESI );
 405         printk("EDI=%08x\n", M.x86.R_EDI );
 406         printk("\tDS=%04x  ", M.x86.R_DS );
 407         printk("ES=%04x  ", M.x86.R_ES );
 408         printk("SS=%04x  ", M.x86.R_SS );
 409         printk("CS=%04x  ", M.x86.R_CS );
 410         printk("EIP=%08x\n\t", M.x86.R_EIP );
 411         if (ACCESS_FLAG(F_OF))    printk("OV ");     /* CHECKED... */
 412         else                        printk("NV ");
 413         if (ACCESS_FLAG(F_DF))    printk("DN ");
 414         else                        printk("UP ");
 415         if (ACCESS_FLAG(F_IF))    printk("EI ");
 416         else                        printk("DI ");
 417         if (ACCESS_FLAG(F_SF))    printk("NG ");
 418         else                        printk("PL ");
 419         if (ACCESS_FLAG(F_ZF))    printk("ZR ");
 420         else                        printk("NZ ");
 421         if (ACCESS_FLAG(F_AF))    printk("AC ");
 422         else                        printk("NA ");
 423         if (ACCESS_FLAG(F_PF))    printk("PE ");
 424         else                        printk("PO ");
 425         if (ACCESS_FLAG(F_CF))    printk("CY ");
 426         else                        printk("NC ");
 427         printk("\n");
 428 }