errors.c 11.1 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11
/*---------------------------------------------------------------------------+
 |  errors.c                                                                 |
 |                                                                           |
 |  The error handling functions for wm-FPU-emu                              |
 |                                                                           |
 | Copyright (C) 1992    W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
 |                       Australia.  E-mail apm233m@vaxc.cc.monash.edu.au    |
 |                                                                           |
 |                                                                           |
 +---------------------------------------------------------------------------*/

12 13 14 15 16 17 18
/*---------------------------------------------------------------------------+
 | Note:                                                                     |
 |    The file contains code which accesses user memory.                     |
 |    Emulator static data may change when user memory is accessed, due to   |
 |    other processes using the emulator while swapping is in progress.      |
 +---------------------------------------------------------------------------*/

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
#include <linux/signal.h>

#include <asm/segment.h>

#include "fpu_system.h"
#include "exception.h"
#include "fpu_emu.h"
#include "status_w.h"
#include "control_w.h"
#include "reg_constant.h"
#include "version.h"

/* */
#undef PRINT_MESSAGES
/* */

void Un_impl(void)
{
37 38 39 40 41
  unsigned char byte1, FPU_modrm;

  RE_ENTRANT_CHECK_OFF
  byte1 = get_fs_byte((unsigned char *) FPU_ORIG_EIP);
  FPU_modrm = get_fs_byte(1 + (unsigned char *) FPU_ORIG_EIP);
42 43 44 45 46 47 48 49

  printk("Unimplemented FPU Opcode at eip=%p : %02x ",
	 FPU_ORIG_EIP, byte1);

  if (FPU_modrm >= 0300)
    printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8, FPU_modrm & 7);
  else
    printk("/%d\n", (FPU_modrm >> 3) & 7);
50
  RE_ENTRANT_CHECK_ON
51 52 53 54 55 56 57 58 59 60 61 62 63

  EXCEPTION(EX_Invalid);

}




void emu_printall()
{
  int i;
  static char *tag_desc[] = { "Valid", "Zero", "ERROR", "ERROR",
                              "DeNorm", "Inf", "NaN", "Empty" };
64 65 66 67 68
  unsigned char byte1, FPU_modrm;

  RE_ENTRANT_CHECK_OFF
  byte1 = get_fs_byte((unsigned char *) FPU_ORIG_EIP);
  FPU_modrm = get_fs_byte(1 + (unsigned char *) FPU_ORIG_EIP);
69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117

#ifdef DEBUGGING
if ( status_word & SW_B ) printk("SW: backward compatibility (=ES)\n");
if ( status_word & SW_C3 ) printk("SW: condition bit 3\n");
if ( status_word & SW_C2 ) printk("SW: condition bit 2\n");
if ( status_word & SW_C1 ) printk("SW: condition bit 1\n");
if ( status_word & SW_C0 ) printk("SW: condition bit 0\n");
if ( status_word & SW_ES ) printk("SW: exception summary\n");
if ( status_word & SW_SF ) printk("SW: stack fault\n");
if ( status_word & SW_PE ) printk("SW: loss of precision\n");
if ( status_word & SW_UE ) printk("SW: underflow\n");
if ( status_word & SW_OE ) printk("SW: overflow\n");
if ( status_word & SW_ZE ) printk("SW: divide by zero\n");
if ( status_word & SW_DE ) printk("SW: denormalized operand\n");
if ( status_word & SW_IE ) printk("SW: invalid operation\n");
#endif DEBUGGING

  status_word = status_word & ~SW_TOP;
  status_word |= (top&7) << SW_TOPS;

  printk("At %p: %02x ", FPU_ORIG_EIP, byte1);
  if (FPU_modrm >= 0300)
    printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8, FPU_modrm & 7);
  else
    printk("/%d, mod=%d rm=%d\n",
	   (FPU_modrm >> 3) & 7, (FPU_modrm >> 6) & 3, FPU_modrm & 7);

  printk(" SW: b=%d st=%d es=%d sf=%d cc=%d%d%d%d ef=%d%d%d%d%d%d\n",
	 status_word & 0x8000 ? 1 : 0,   /* busy */
	 (status_word & 0x3800) >> 11,   /* stack top pointer */
	 status_word & 0x80 ? 1 : 0,     /* Error summary status */
	 status_word & 0x40 ? 1 : 0,     /* Stack flag */
	 status_word & SW_C3?1:0, status_word & SW_C2?1:0, /* cc */
	 status_word & SW_C1?1:0, status_word & SW_C0?1:0, /* cc */
	 status_word & SW_PE?1:0, status_word & SW_UE?1:0, /* exception fl */
	 status_word & SW_OE?1:0, status_word & SW_ZE?1:0, /* exception fl */
	 status_word & SW_DE?1:0, status_word & SW_IE?1:0); /* exception fl */
  
printk(" CW: ic=%d rc=%d%d pc=%d%d iem=%d     ef=%d%d%d%d%d%d\n",
	 control_word & 0x1000 ? 1 : 0,
	 (control_word & 0x800) >> 11, (control_word & 0x400) >> 10,
	 (control_word & 0x200) >> 9, (control_word & 0x100) >> 8,
	 control_word & 0x80 ? 1 : 0,
	 control_word & SW_PE?1:0, control_word & SW_UE?1:0, /* exception */
	 control_word & SW_OE?1:0, control_word & SW_ZE?1:0, /* exception */
	 control_word & SW_DE?1:0, control_word & SW_IE?1:0); /* exception */

  for ( i = 0; i < 8; i++ )
    {
118
      FPU_REG *r = &st(i);
119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154
      switch (r->tag)
	{
	case TW_Empty:
	  continue;
	  break;
	case TW_Zero:
	  printk("st(%d)  %c .0000 0000 0000 0000         ",
		 i, r->sign ? '-' : '+');
	  break;
	case TW_Valid:
	case TW_NaN:
	case TW_Denormal:
	case TW_Infinity:
	  printk("st(%d)  %c .%04x %04x %04x %04x e%+-6d ", i,
		 r->sign ? '-' : '+',
		 (long)(r->sigh >> 16),
		 (long)(r->sigh & 0xFFFF),
		 (long)(r->sigl >> 16),
		 (long)(r->sigl & 0xFFFF),
		 r->exp - EXP_BIAS + 1);
	  break;
	default:
	  printk("Whoops! Error in errors.c      ");
	  break;
	}
      printk("%s\n", tag_desc[(int) (unsigned) r->tag]);
    }

  printk("[data] %c .%04x %04x %04x %04x e%+-6d ",
	 FPU_loaded_data.sign ? '-' : '+',
	 (long)(FPU_loaded_data.sigh >> 16),
	 (long)(FPU_loaded_data.sigh & 0xFFFF),
	 (long)(FPU_loaded_data.sigl >> 16),
	 (long)(FPU_loaded_data.sigl & 0xFFFF),
	 FPU_loaded_data.exp - EXP_BIAS + 1);
  printk("%s\n", tag_desc[(int) (unsigned) FPU_loaded_data.tag]);
155
  RE_ENTRANT_CHECK_ON
156 157 158 159 160 161 162

}

static struct {
  int type;
  char *name;
} exception_names[] = {
163 164 165 166 167 168 169 170 171 172
  { EX_StackOver, "stack overflow" },
  { EX_StackUnder, "stack underflow" },
  { EX_Precision, "loss of precision" },
  { EX_Underflow, "underflow" },
  { EX_Overflow, "overflow" },
  { EX_ZeroDiv, "divide by zero" },
  { EX_Denormal, "denormalized operand" },
  { EX_Invalid, "invalid operation" },
  { EX_INTERNAL, "INTERNAL BUG in "FPU_VERSION },
  { 0, NULL }
173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222
};

/*
 EX_INTERNAL is always given with a code which indicates where the
 error was detected.

 Internal error types:
       0x14   in e14.c
       0x1nn  in a *.c file:
              0x101  in reg_add_sub.c
              0x102  in reg_mul.c
              0x103  in poly_sin.c
              0x104  in poly_tan.c
              0x105  in reg_mul.c
	      0x106  in reg_mov.c
              0x107  in fpu_trig.c
	      0x108  in reg_compare.c
	      0x109  in reg_compare.c
	      0x110  in reg_add_sub.c
	      0x111  in interface.c
	      0x112  in fpu_trig.c
	      0x113  in reg_add_sub.c
	      0x114  in reg_ld_str.c
	      0x115  in fpu_trig.c
	      0x116  in fpu_trig.c
	      0x117  in fpu_trig.c
	      0x118  in fpu_trig.c
	      0x119  in fpu_trig.c
	      0x120  in poly_atan.c
	      0x121  in reg_compare.c
	      0x122  in reg_compare.c
	      0x123  in reg_compare.c
       0x2nn  in an *.s file:
              0x201  in reg_u_add.S
              0x202  in reg_u_div.S
              0x203  in reg_u_div.S
              0x204  in reg_u_div.S
              0x205  in reg_u_mul.S
              0x206  in reg_u_sub.S
              0x207  in wm_sqrt.S
	      0x208  in reg_div.S
              0x209  in reg_u_sub.S
              0x210  in reg_u_sub.S
              0x211  in reg_u_sub.S
              0x212  in reg_u_sub.S
 */

void exception(int n)
{
  int i, int_type;
223

224
  int_type = 0;         /* Needed only to stop compiler warnings */
225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240
  if ( n & EX_INTERNAL )
    {
      int_type = n - EX_INTERNAL;
      n = EX_INTERNAL;
      /* Set lots of exception bits! */
      status_word |= (0x3f | EX_ErrorSummary | FPU_BUSY);
    }
  else
    {
      /* Set the corresponding exception bit */
      status_word |= (n | EX_ErrorSummary | FPU_BUSY);
      if (n == EX_StackUnder)    /* Stack underflow */
	/* This bit distinguishes over- from underflow */
	status_word &= ~SW_C1;
    }

241
  RE_ENTRANT_CHECK_OFF
242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274
  if ( (~control_word & n & CW_EXM) || (n == EX_INTERNAL) )
    {
#ifdef PRINT_MESSAGES
      /* My message from the sponsor */
      printk(FPU_VERSION" "__DATE__" (C) W. Metzenthen.\r\n");
#endif PRINT_MESSAGES
      
      /* Get a name string for error reporting */
      for (i=0; exception_names[i].type; i++)
	if (exception_names[i].type == n)
	  break;
      
      if (exception_names[i].type)
	{
#ifdef PRINT_MESSAGES
	  printk("FP Exception: %s!\n", exception_names[i].name);
#endif PRINT_MESSAGES
	}
      else
	printk("FP emulator: Unknown Exception: 0x%04x!\n", n);
      
      if ( n == EX_INTERNAL )
	{
	  printk("FP emulator: Internal error type 0x%04x\n", int_type);
	  emu_printall();
	}
#ifdef PRINT_MESSAGES
      else
	emu_printall();
#endif PRINT_MESSAGES

      send_sig(SIGFPE, current, 1);
    }
275
  RE_ENTRANT_CHECK_ON
276 277 278 279 280 281 282 283 284 285 286

#ifdef __DEBUG__
  math_abort(FPU_info,SIGFPE);
#endif __DEBUG__

  /* Cause the look-ahead mechanism to terminate */
  FPU_lookahead = 0;
}


/* Real operation attempted on two operands, one a NaN */
287
void real_2op_NaN(FPU_REG *a, FPU_REG *b, FPU_REG *dest)
288
{
289
  FPU_REG *x;
290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327
  
  x = a;
  if (a->tag == TW_NaN)
    {
      if (b->tag == TW_NaN)
	{
	  /* find the "larger" */
	  if ( *(long long *)&(a->sigl) < *(long long *)&(b->sigl) )
	    x = b;
	}
      /* else return the quiet version of the NaN in a */
    }
  else if (b->tag == TW_NaN)
    {
      x = b;
    }
#ifdef PARANOID
  else
    {
      EXCEPTION(EX_INTERNAL|0x113);
      x = &CONST_QNaN;
    }
#endif PARANOID
  
  if ( control_word & EX_Invalid )
    {
      /* The masked response */
      reg_move(x, dest);
      /* ensure a Quiet NaN */
      dest->sigh |= 0x40000000;
    }

  EXCEPTION(EX_Invalid);
  
  return;
}

/* Invalid arith operation on valid registers */
328
void arith_invalid(FPU_REG *dest)
329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344
{
  
  if ( control_word & EX_Invalid )
    {
      /* The masked response */
      reg_move(&CONST_QNaN, dest);
    }

  EXCEPTION(EX_Invalid);
  
  return;

}


/* Divide a finite number by zero */
345
void divide_by_zero(int sign, FPU_REG *dest)
346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361
{

  if ( control_word & EX_ZeroDiv )
    {
      /* The masked response */
      reg_move(&CONST_INF, dest);
      dest->sign = (unsigned char)sign;
    }
 
  EXCEPTION(EX_ZeroDiv);

  return;

}


362
void arith_overflow(FPU_REG *dest)
363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385
{

  if ( control_word & EX_Overflow )
    {
      char sign;
      /* The masked response */
      sign = dest->sign;
      reg_move(&CONST_INF, dest);
      dest->sign = sign;
    }
  else
    {
      /* Subtract the magic number from the exponent */
      dest->exp -= (3 * (1 << 13));
    }

  EXCEPTION(EX_Overflow);

  return;

}


386
void arith_underflow(FPU_REG *dest)
387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413
{

  if ( control_word & EX_Underflow )
    {
      /* The masked response */
      if ( dest->exp <= EXP_UNDER - 63 )
	reg_move(&CONST_Z, dest);
    }
  else
    {
      /* Add the magic number to the exponent */
      dest->exp += (3 * (1 << 13));
    }

  EXCEPTION(EX_Underflow);

  return;
}


void stack_overflow(void)
{

 if ( control_word & EX_Invalid )
    {
      /* The masked response */
      top--;
414
      reg_move(&CONST_QNaN, FPU_st0_ptr = &st(0));
415 416 417 418 419 420 421 422 423 424 425 426 427 428 429
    }

  EXCEPTION(EX_StackOver);

  return;

}


void stack_underflow(void)
{

 if ( control_word & EX_Invalid )
    {
      /* The masked response */
430
      reg_move(&CONST_QNaN, FPU_st0_ptr);
431 432 433 434 435 436 437 438
    }

  EXCEPTION(EX_StackUnder);

  return;

}