mono/mini/exceptions-s390.c

   1 /*------------------------------------------------------------------*/
   2 /*                                                                  */
   3 /* Name        - exceptions-s390.c                                  */
   4 /*                                                                  */
   5 /* Function    - Exception support for S/390.                       */
   6 /*                                                                  */
   7 /* Name        - Neale Ferguson (Neale.Ferguson@SoftwareAG-usa.com) */
   8 /*                                                                  */
   9 /* Date        - January, 2004                                      */
  10 /*                                                                  */
  11 /* Derivation  - From exceptions-x86 & exceptions-ppc               */
  12 /*               Paolo Molaro (lupus@ximian.com)                    */
  13 /*               Dietmar Maurer (dietmar@ximian.com)                */
  14 /*                                                                  */
  15 /* Copyright   - 2001 Ximian, Inc.                                  */
  16 /*                                                                  */
  17 /*------------------------------------------------------------------*/
  18
  19 /*------------------------------------------------------------------*/
  20 /*                 D e f i n e s                                    */
  21 /*------------------------------------------------------------------*/
  22
  23 #define S390_CALLFILTER_INTREGS         S390_MINIMAL_STACK_SIZE
  24 #define S390_CALLFILTER_FLTREGS         S390_CALLFILTER_INTREGS+(16*sizeof(gulong))
  25 #define S390_CALLFILTER_ACCREGS         S390_CALLFILTER_FLTREGS+(16*sizeof(gdouble))
  26 #define S390_CALLFILTER_SIZE            (S390_CALLFILTER_ACCREGS+(16*sizeof(gulong)))
  27
  28 #define S390_THROWSTACK_ACCPRM          S390_MINIMAL_STACK_SIZE
  29 #define S390_THROWSTACK_FPCPRM          S390_THROWSTACK_ACCPRM+sizeof(gpointer)
  30 #define S390_THROWSTACK_RETHROW         S390_THROWSTACK_FPCPRM+sizeof(gulong)
  31 #define S390_THROWSTACK_INTREGS         S390_THROWSTACK_RETHROW+sizeof(gboolean)
  32 #define S390_THROWSTACK_FLTREGS         S390_THROWSTACK_INTREGS+(16*sizeof(gulong))
  33 #define S390_THROWSTACK_ACCREGS         S390_THROWSTACK_FLTREGS+(16*sizeof(gdouble))
  34 #define S390_THROWSTACK_SIZE            (S390_THROWSTACK_ACCREGS+(16*sizeof(gulong)))
  35
  36 #define SZ_THROW        384
  37
  38 /*========================= End of Defines =========================*/
  39
  40 /*------------------------------------------------------------------*/
  41 /*                 I n c l u d e s                                  */
  42 /*------------------------------------------------------------------*/
  43
  44 #include <config.h>
  45 #include <glib.h>
  46 #include <signal.h>
  47 #include <string.h>
  48 #include <ucontext.h>
  49
  50 #include <mono/arch/s390/s390-codegen.h>
  51 #include <mono/metadata/appdomain.h>
  52 #include <mono/metadata/tabledefs.h>
  53 #include <mono/metadata/threads.h>
  54 #include <mono/metadata/debug-helpers.h>
  55 #include <mono/metadata/exception.h>
  56 #include <mono/metadata/mono-debug.h>
  57
  58 #include "mini.h"
  59 #include "mini-s390.h"
  60
  61 /*========================= End of Includes ========================*/
  62
  63 /*------------------------------------------------------------------*/
  64 /*                   P r o t o t y p e s                            */
  65 /*------------------------------------------------------------------*/
  66
  67 gboolean mono_arch_handle_exception (void     *ctx,
  68                                      gpointer obj,
  69                                      gboolean test_only);
  70
  71 /*========================= End of Prototypes ======================*/
  72
  73 /*------------------------------------------------------------------*/
  74 /*                 G l o b a l   V a r i a b l e s                  */
  75 /*------------------------------------------------------------------*/
  76
  77 /*====================== End of Global Variables ===================*/
  78
  79 /*------------------------------------------------------------------*/
  80 /*                                                                  */
  81 /* Name         - mono_arch_has_unwind_info                         */
  82 /*                                                                  */
  83 /* Function     - Tests if a function has a DWARF exception table   */
  84 /*                that is able to restore all caller saved registers*/
  85 /*                                                                  */
  86 /*------------------------------------------------------------------*/
  87
  88 gboolean
  89 mono_arch_has_unwind_info (gconstpointer addr)
  90 {
  91         return FALSE;
  92 }
  93
  94 /*========================= End of Function ========================*/
  95
  96 /*------------------------------------------------------------------*/
  97 /*                                                                  */
  98 /* Name         - mono_arch_get_call_filter                         */
  99 /*                                                                  */
 100 /* Function     - Return a pointer to a method which calls an       */
 101 /*                exception filter. We also use this function to    */
 102 /*                call finally handlers (we pass NULL as @exc       */
 103 /*                object in this case).                             */
 104 /*                                                                  */
 105 /*------------------------------------------------------------------*/
 106
 107 gpointer
 108 mono_arch_get_call_filter (MonoTrampInfo **info, gboolean aot)
 109 {
 110         static guint8 *start;
 111         static int inited = 0;
 112         guint8 *code;
 113         int alloc_size, pos, i;
 114
 115         g_assert (!aot);
 116         if (info)
 117                 *info = NULL;
 118
 119         if (inited)
 120                 return start;
 121
 122         inited = 1;
 123         /* call_filter (MonoContext *ctx, unsigned long eip, gpointer exc) */
 124         code = start = mono_global_codeman_reserve (512);
 125
 126         s390_stm (code, s390_r6, s390_r14, STK_BASE, S390_REG_SAVE_OFFSET);
 127         s390_lr  (code, s390_r14, STK_BASE);
 128         alloc_size = S390_ALIGN(S390_CALLFILTER_SIZE, S390_STACK_ALIGNMENT);
 129         s390_ahi (code, STK_BASE, -alloc_size);
 130         s390_st  (code, s390_r14, 0, STK_BASE, 0);
 131
 132         /*------------------------------------------------------*/
 133         /* save general registers on stack                      */
 134         /*------------------------------------------------------*/
 135         s390_stm (code, s390_r0, s390_r13, STK_BASE, S390_CALLFILTER_INTREGS);
 136
 137         /*------------------------------------------------------*/
 138         /* save floating point registers on stack               */
 139         /*------------------------------------------------------*/
 140 //      pos = S390_CALLFILTER_FLTREGS;
 141 //      for (i = 0; i < 16; ++i) {
 142 //              s390_std (code, i, 0, STK_BASE, pos);
 143 //              pos += sizeof (gdouble);
 144 //      }
 145
 146         /*------------------------------------------------------*/
 147         /* save access registers on stack                       */
 148         /*------------------------------------------------------*/
 149 //      s390_stam (code, s390_a0, s390_a15, STK_BASE, S390_CALLFILTER_ACCREGS);
 150
 151         /*------------------------------------------------------*/
 152         /* Get A(Context)                                       */
 153         /*------------------------------------------------------*/
 154         s390_lr   (code, s390_r13, s390_r2);
 155
 156         /*------------------------------------------------------*/
 157         /* Get A(Handler Entry Point)                           */
 158         /*------------------------------------------------------*/
 159         s390_lr   (code, s390_r0, s390_r3);
 160
 161         /*------------------------------------------------------*/
 162         /* Set parameter register with Exception                */
 163         /*------------------------------------------------------*/
 164         s390_lr   (code, s390_r2, s390_r4);
 165
 166         /*------------------------------------------------------*/
 167         /* Load all registers with values from the context      */
 168         /*------------------------------------------------------*/
 169         s390_lm   (code, s390_r3, s390_r12, s390_r13,
 170                    G_STRUCT_OFFSET(MonoContext, uc_mcontext.gregs[3]));
 171         pos = G_STRUCT_OFFSET(MonoContext, uc_mcontext.fpregs.fprs[0]);
 172         for (i = 0; i < 16; ++i) {
 173                 s390_ld  (code, i, 0, s390_r13, pos);
 174                 pos += sizeof(gdouble);
 175         }
 176
 177         /*------------------------------------------------------*/
 178         /* Point at the copied stack frame and call the filter  */
 179         /*------------------------------------------------------*/
 180         s390_lr   (code, s390_r1, s390_r0);
 181         s390_basr (code, s390_r14, s390_r1);
 182
 183         /*------------------------------------------------------*/
 184         /* Save return value                                    */
 185         /*------------------------------------------------------*/
 186         s390_lr   (code, s390_r14, s390_r2);
 187
 188         /*------------------------------------------------------*/
 189         /* Restore all the regs from the stack                  */
 190         /*------------------------------------------------------*/
 191         s390_lm (code, s390_r0, s390_r13, STK_BASE, S390_CALLFILTER_INTREGS);
 192 //      pos = S390_CALLFILTER_FLTREGS;
 193 //      for (i = 0; i < 16; ++i) {
 194 //              s390_ld (code, i, 0, STK_BASE, pos);
 195 //              pos += sizeof (gdouble);
 196 //      }
 197
 198         s390_lr   (code, s390_r2, s390_r14);
 199 //      s390_lam  (code, s390_a0, s390_a15, STK_BASE, S390_CALLFILTER_ACCREGS);
 200         s390_ahi  (code, s390_r15, alloc_size);
 201         s390_lm   (code, s390_r6, s390_r14, STK_BASE, S390_REG_SAVE_OFFSET);
 202         s390_br   (code, s390_r14);
 203
 204         g_assert ((code - start) < SZ_THROW);
 205         return start;
 206 }
 207
 208 /*========================= End of Function ========================*/
 209
 210 /*------------------------------------------------------------------*/
 211 /*                                                                  */
 212 /* Name         - throw_exception.                                  */
 213 /*                                                                  */
 214 /* Function     - Raise an exception based on the parameters passed.*/
 215 /*                                                                  */
 216 /*------------------------------------------------------------------*/
 217
 218 static void
 219 throw_exception (MonoObject *exc, unsigned long ip, unsigned long sp,
 220                  gulong *int_regs, gdouble *fp_regs, gulong *acc_regs,
 221                  guint fpc, gboolean rethrow)
 222 {
 223         MonoContext ctx;
 224         int iReg;
 225
 226         memset(&ctx, 0, sizeof(ctx));
 227
 228         getcontext(&ctx);
 229
 230         /* adjust eip so that it point into the call instruction */
 231         ip -= 6;
 232
 233         for (iReg = 0; iReg < 16; iReg++) {
 234                 ctx.uc_mcontext.gregs[iReg]         = int_regs[iReg];
 235                 ctx.uc_mcontext.fpregs.fprs[iReg].d = fp_regs[iReg];
 236                 ctx.uc_mcontext.aregs[iReg]         = acc_regs[iReg];
 237         }
 238
 239         ctx.uc_mcontext.fpregs.fpc = fpc;
 240
 241         MONO_CONTEXT_SET_BP (&ctx, sp);
 242         MONO_CONTEXT_SET_IP (&ctx, ip);
 243
 244         if (mono_object_isinst (exc, mono_defaults.exception_class)) {
 245                 MonoException *mono_ex = (MonoException*)exc;
 246                 if (!rethrow)
 247                         mono_ex->stack_trace = NULL;
 248         }
 249         mono_arch_handle_exception (&ctx, exc, FALSE);
 250         setcontext(&ctx);
 251
 252         g_assert_not_reached ();
 253 }
 254
 255 /*========================= End of Function ========================*/
 256
 257 /*------------------------------------------------------------------*/
 258 /*                                                                  */
 259 /* Name         - get_throw_exception_generic                       */
 260 /*                                                                  */
 261 /* Function     - Return a function pointer which can be used to    */
 262 /*                raise exceptions. The returned function has the   */
 263 /*                following signature:                              */
 264 /*                void (*func) (MonoException *exc); or,            */
 265 /*                void (*func) (char *exc_name);                    */
 266 /*                                                                  */
 267 /*------------------------------------------------------------------*/
 268
 269 static gpointer
 270 get_throw_exception_generic (guint8 *start, int size,
 271                              int by_name, gboolean rethrow)
 272 {
 273         guint8 *code;
 274         int alloc_size, pos, i, offset;
 275
 276         code = start;
 277
 278         s390_stm (code, s390_r6, s390_r14, STK_BASE, S390_REG_SAVE_OFFSET);
 279         alloc_size = S390_ALIGN(S390_THROWSTACK_SIZE, S390_STACK_ALIGNMENT);
 280         s390_lr   (code, s390_r14, STK_BASE);
 281         s390_ahi  (code, STK_BASE, -alloc_size);
 282         s390_st   (code, s390_r14, 0, STK_BASE, 0);
 283         if (by_name) {
 284                 s390_lr   (code, s390_r4, s390_r2);
 285                 s390_bras (code, s390_r13, 6);
 286                 s390_word (code, mono_defaults.corlib);
 287                 s390_word (code, "System");
 288                 s390_l    (code, s390_r2, 0, s390_r13, 0);
 289                 s390_l    (code, s390_r3, 0, s390_r13, 4);
 290                 offset = (guint32) S390_RELATIVE(mono_exception_from_name, code);
 291                 s390_brasl(code, s390_r14, offset);
 292         }
 293         /*------------------------------------------------------*/
 294         /* save the general registers on the stack              */
 295         /*------------------------------------------------------*/
 296         s390_stm (code, s390_r0, s390_r13, STK_BASE, S390_THROWSTACK_INTREGS);
 297
 298         s390_lr  (code, s390_r1, STK_BASE);
 299         s390_ahi (code, s390_r1, alloc_size);
 300         /*------------------------------------------------------*/
 301         /* save the return address in the parameter register    */
 302         /*------------------------------------------------------*/
 303         s390_l   (code, s390_r3, 0, s390_r1, S390_RET_ADDR_OFFSET);
 304
 305         /*------------------------------------------------------*/
 306         /* save the floating point registers                    */
 307         /*------------------------------------------------------*/
 308         pos = S390_THROWSTACK_FLTREGS;
 309         for (i = 0; i < 16; ++i) {
 310                 s390_std (code, i, 0,STK_BASE, pos);
 311                 pos += sizeof (gdouble);
 312         }
 313         /*------------------------------------------------------*/
 314         /* save the access registers                            */
 315         /*------------------------------------------------------*/
 316         s390_stam (code, s390_r0, s390_r15, STK_BASE, S390_THROWSTACK_ACCREGS);
 317
 318         /*------------------------------------------------------*/
 319         /* call throw_exception (exc, ip, sp, gr, fr, ar)       */
 320         /* exc is already in place in r2                        */
 321         /*------------------------------------------------------*/
 322         s390_lr   (code, s390_r4, s390_r1);        /* caller sp */
 323         /*------------------------------------------------------*/
 324         /* pointer to the saved int regs                        */
 325         /*------------------------------------------------------*/
 326         s390_la   (code, s390_r5, 0, STK_BASE, S390_THROWSTACK_INTREGS);
 327         s390_la   (code, s390_r6, 0, STK_BASE, S390_THROWSTACK_FLTREGS);
 328         s390_la   (code, s390_r7, 0, STK_BASE, S390_THROWSTACK_ACCREGS);
 329         s390_st   (code, s390_r7, 0, STK_BASE, S390_THROWSTACK_ACCPRM);
 330         s390_stfpc(code, STK_BASE, S390_THROWSTACK_FPCPRM);
 331         s390_lhi  (code, s390_r7, rethrow);
 332         s390_st   (code, s390_r7, 0, STK_BASE, S390_THROWSTACK_RETHROW);
 333         offset = (guint32) S390_RELATIVE(throw_exception, code);
 334         s390_brasl(code, s390_r14, offset);
 335         /* we should never reach this breakpoint */
 336         s390_break (code);
 337         g_assert ((code - start) < size);
 338         return start;
 339 }
 340
 341 /*========================= End of Function ========================*/
 342
 343 /*------------------------------------------------------------------*/
 344 /*                                                                  */
 345 /* Name         - arch_get_throw_exception                          */
 346 /*                                                                  */
 347 /* Function     - Return a function pointer which can be used to    */
 348 /*                raise exceptions. The returned function has the   */
 349 /*                following signature:                              */
 350 /*                void (*func) (MonoException *exc);                */
 351 /*                                                                  */
 352 /*------------------------------------------------------------------*/
 353
 354 gpointer
 355 mono_arch_get_throw_exception (MonoTrampInfo **info, gboolean aot)
 356 {
 357         static guint8 *start;
 358         static int inited = 0;
 359
 360         g_assert (!aot);
 361         if (info)
 362                 *info = NULL;
 363
 364         if (inited)
 365                 return start;
 366         start = mono_global_codeman_reserve (SZ_THROW);
 367         get_throw_exception_generic (start, SZ_THROW, FALSE, FALSE);
 368         inited = 1;
 369         return start;
 370 }
 371
 372 /*========================= End of Function ========================*/
 373
 374 /*------------------------------------------------------------------*/
 375 /*                                                                  */
 376 /* Name         - arch_get_rethrow_exception                        */
 377 /*                                                                  */
 378 /* Function     - Return a function pointer which can be used to    */
 379 /*                raise exceptions. The returned function has the   */
 380 /*                following signature:                              */
 381 /*                void (*func) (MonoException *exc);                */
 382 /*                                                                  */
 383 /*------------------------------------------------------------------*/
 384
 385 gpointer
 386 mono_arch_get_rethrow_exception (MonoTrampInfo **info, gboolean aot)
 387 {
 388         static guint8 *start;
 389         static int inited = 0;
 390
 391         g_assert (!aot);
 392         if (info)
 393                 *info = NULL;
 394
 395         if (inited)
 396                 return start;
 397         start = mono_global_codeman_reserve (SZ_THROW);
 398         get_throw_exception_generic (start, SZ_THROW, FALSE, TRUE);
 399         inited = 1;
 400         return start;
 401 }
 402
 403 /*========================= End of Function ========================*/
 404
 405 /*------------------------------------------------------------------*/
 406 /*                                                                  */
 407 /* Name         - arch_get_throw_exception_by_name                  */
 408 /*                                                                  */
 409 /* Function     - Return a function pointer which can be used to    */
 410 /*                raise corlib exceptions. The return function has  */
 411 /*                the following signature:                          */
 412 /*                void (*func) (char *exc_name);                    */
 413 /*                                                                  */
 414 /*------------------------------------------------------------------*/
 415
 416 gpointer
 417 mono_arch_get_throw_exception_by_name (void)
 418 {
 419         static guint8 *start;
 420         static int inited = 0;
 421
 422         if (inited)
 423                 return start;
 424         start = mono_global_codeman_reserve (SZ_THROW);
 425         get_throw_exception_generic (start, SZ_THROW, TRUE, FALSE);
 426         inited = 1;
 427         return start;
 428 }
 429
 430 /*========================= End of Function ========================*/
 431
 432 /*------------------------------------------------------------------*/
 433 /*                                                                  */
 434 /* Name         - mono_arch_find_jit_info                           */
 435 /*                                                                  */
 436 /* Function     - This function is used to gather informatoin from  */
 437 /*                @ctx. It returns the MonoJitInfo of the corres-   */
 438 /*                ponding function, unwinds one stack frame and     */
 439 /*                stores the resulting context into @new_ctx. It    */
 440 /*                also stores a string describing the stack location*/
 441 /*                into @trace (if not NULL), and modifies the @lmf  */
 442 /*                if necessary. @native_offset returns the IP off-  */
 443 /*                set from the start of the function or -1 if that  */
 444 /*                informatoin is not available.                     */
 445 /*                                                                  */
 446 /*------------------------------------------------------------------*/
 447
 448 MonoJitInfo *
 449 mono_arch_find_jit_info (MonoDomain *domain, MonoJitTlsData *jit_tls,
 450                          MonoJitInfo *res, MonoJitInfo *prev_ji, MonoContext *ctx,
 451                          MonoContext *new_ctx, MonoLMF **lmf, gboolean *managed)
 452 {
 453         MonoJitInfo *ji;
 454         gpointer ip = MONO_CONTEXT_GET_IP (ctx);
 455         MonoS390StackFrame *sframe;
 456
 457         if (prev_ji &&
 458             (ip >= prev_ji->code_start &&
 459             ((guint8 *) ip <= ((guint8 *) prev_ji->code_start) + prev_ji->code_size)))
 460                 ji = prev_ji;
 461         else
 462                 ji = mini_jit_info_table_find (domain, ip, NULL);
 463
 464         if (managed)
 465                 *managed = FALSE;
 466
 467         if (ji != NULL) {
 468                 gint32 address;
 469
 470                 *new_ctx = *ctx;
 471
 472                 if (*lmf && (MONO_CONTEXT_GET_SP (ctx) >= (gpointer)(*lmf)->ebp)) {
 473                         /* remove any unused lmf */
 474                         *lmf = (*lmf)->previous_lmf;
 475                 }
 476
 477                 address = (char *)ip - (char *)ji->code_start;
 478
 479                 if (managed)
 480                         if (!ji->method->wrapper_type)
 481                                 *managed = TRUE;
 482
 483                 sframe = (MonoS390StackFrame *) MONO_CONTEXT_GET_SP (ctx);
 484                 MONO_CONTEXT_SET_BP (new_ctx, sframe->prev);
 485                 sframe = (MonoS390StackFrame *) sframe->prev;
 486                 MONO_CONTEXT_SET_IP (new_ctx, sframe->return_address);
 487                 memcpy (&new_ctx->uc_mcontext.gregs[6], sframe->regs, (8*sizeof(gint32)));
 488                 return ji;
 489         } else if (*lmf) {
 490
 491                 *new_ctx = *ctx;
 492
 493                 if (!(*lmf)->method)
 494                         return (gpointer)-1;
 495
 496                 if ((ji = mini_jit_info_table_find (domain, (gpointer)(*lmf)->eip, NULL))) {
 497                 } else {
 498                         memset (res, 0, MONO_SIZEOF_JIT_INFO);
 499                         res->method = (*lmf)->method;
 500                 }
 501
 502                 memcpy(new_ctx->uc_mcontext.gregs, (*lmf)->gregs, sizeof((*lmf)->gregs));
 503                 memcpy(new_ctx->uc_mcontext.fpregs.fprs, (*lmf)->fregs, sizeof((*lmf)->fregs));
 504
 505                 MONO_CONTEXT_SET_BP (new_ctx, (*lmf)->ebp);
 506                 MONO_CONTEXT_SET_IP (new_ctx, (*lmf)->eip);
 507                 *lmf = (*lmf)->previous_lmf;
 508
 509                 return ji ? ji : res;
 510         }
 511
 512         return NULL;
 513 }
 514
 515 /*========================= End of Function ========================*/
 516
 517 /*------------------------------------------------------------------*/
 518 /*                                                                  */
 519 /* Name         - mono_arch_handle_exception                        */
 520 /*                                                                  */
 521 /* Function     - Handle an exception raised by the JIT code.       */
 522 /*                                                                  */
 523 /* Parameters   - ctx       - Saved processor state                 */
 524 /*                obj       - The exception object                  */
 525 /*                test_only - Only test if the exception is caught, */
 526 /*                            but don't call handlers               */
 527 /*                                                                  */
 528 /*------------------------------------------------------------------*/
 529
 530 gboolean
 531 mono_arch_handle_exception (void *uc, gpointer obj, gboolean test_only)
 532 {
 533         return mono_handle_exception (uc, obj, mono_arch_ip_from_context(uc), test_only);
 534 }
 535
 536 /*========================= End of Function ========================*/
 537
 538 /*------------------------------------------------------------------*/
 539 /*                                                                  */
 540 /* Name         - mono_arch_ip_from_context                         */
 541 /*                                                                  */
 542 /* Function     - Return the instruction pointer from the context.  */
 543 /*                                                                  */
 544 /* Parameters   - sigctx    - Saved processor state                 */
 545 /*                                                                  */
 546 /*------------------------------------------------------------------*/
 547
 548 gpointer
 549 mono_arch_ip_from_context (void *sigctx)
 550 {
 551         return context_get_ip (sigctx);
 552 }
 553
 554
 555 /*========================= End of Function ========================*/
 556
 557 /*------------------------------------------------------------------*/
 558 /*                                                                  */
 559 /* Name         - mono_arch_get_restore_context                    */
 560 /*                                                                  */
 561 /* Function     - Return the address of the routine that will rest- */
 562 /*                ore the context.                                  */
 563 /*                                                                  */
 564 /*------------------------------------------------------------------*/
 565
 566 gpointer
 567 mono_arch_get_restore_context (MonoTrampInfo **info, gboolean aot)
 568 {
 569         g_assert (!aot);
 570         if (info)
 571                 *info = NULL;
 572
 573         return setcontext;
 574 }
 575
 576
 577 /*========================= End of Function ========================*/
 578
 579 /*------------------------------------------------------------------*/
 580 /*                                                                  */
 581 /* Name         - mono_arch_is_int_overflow                         */
 582 /*                                                                  */
 583 /* Function     - Inspect the code that raised the SIGFPE signal    */
 584 /*                to see if the DivideByZero or Arithmetic exception*/
 585 /*                should be raised.                                 */
 586 /*                                                                  */
 587 /*------------------------------------------------------------------*/
 588
 589 gboolean
 590 mono_arch_is_int_overflow (void *uc, void *info)
 591 {
 592         MonoContext *ctx;
 593         guint8      *code;
 594         guint32     *operand;
 595         gboolean    arithExc = TRUE;
 596         gint        regNo,
 597                     offset;
 598
 599         ctx  = (MonoContext *) uc;
 600         code =  (guint8 *) ((siginfo_t *)info)->si_addr;
 601         /*----------------------------------------------------------*/
 602         /* Divide operations are the only ones that will give the   */
 603         /* divide by zero exception so just check for these ops.    */
 604         /*----------------------------------------------------------*/
 605         switch (code[0]) {
 606                 case 0x1d :             /* Divide Register          */
 607                         regNo = code[1] & 0x0f;
 608                         if (ctx->uc_mcontext.gregs[regNo] == 0)
 609                                 arithExc = FALSE;
 610                 break;
 611                 case 0x5d :             /* Divide                   */
 612                         regNo   = (code[2] & 0xf0 >> 8);
 613                         offset  = *((guint16 *) code+2) & 0x0fff;
 614                         operand = (guint32*)(ctx->uc_mcontext.gregs[regNo] + offset);
 615                         if (*operand == 0)
 616                                 arithExc = FALSE;
 617                 break;
 618                 case 0xb9 :             /* Divide logical Register? */
 619                         if (code[1] == 0x97) {
 620                                 regNo = (code[2] & 0xf0 >> 8);
 621                                 if (ctx->uc_mcontext.gregs[regNo] == 0)
 622                                         arithExc = FALSE;
 623                         }
 624                 break;
 625                 case 0xe3 :             /* Divide logical?          */
 626                         if (code[1] == 0x97) {
 627                                 regNo   = (code[2] & 0xf0 >> 8);
 628                                 offset  = *((guint32 *) code+1) & 0x000fffff;
 629                                 operand = (guint32*)(ctx->uc_mcontext.gregs[regNo] + offset);
 630                                 if (*operand == 0)
 631                                         arithExc = FALSE;
 632                         }
 633                 break;
 634                 default:
 635                         arithExc = TRUE;
 636         }
 637         ctx->uc_mcontext.psw.addr = (guint32)code;
 638         return (arithExc);
 639 }
 640
 641 /*========================= End of Function ========================*/