kernel/FPU-emu/errors.c

/* */
This source file includes following definitions.
Un_impl
emu_printall
exception
real_2op_NaN
arith_invalid
divide_by_zero
arith_overflow
arith_underflow
stack_overflow
stack_underflow
   1 /*---------------------------------------------------------------------------+
   2  |  errors.c                                                                 |
   3  |                                                                           |
   4  |  The error handling functions for wm-FPU-emu                              |
   5  |                                                                           |
   6  | Copyright (C) 1992    W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
   7  |                       Australia.  E-mail apm233m@vaxc.cc.monash.edu.au    |
   8  |                                                                           |
   9  |                                                                           |
  10  +---------------------------------------------------------------------------*/
  11 
  12 /*---------------------------------------------------------------------------+
  13  | Note:                                                                     |
  14  |    The file contains code which accesses user memory.                     |
  15  |    Emulator static data may change when user memory is accessed, due to   |
  16  |    other processes using the emulator while swapping is in progress.      |
  17  +---------------------------------------------------------------------------*/
  18 
  19 #include <linux/signal.h>
  20 
  21 #include <asm/segment.h>
  22 
  23 #include "fpu_system.h"
  24 #include "exception.h"
  25 #include "fpu_emu.h"
  26 #include "status_w.h"
  27 #include "control_w.h"
  28 #include "reg_constant.h"
  29 #include "version.h"
  30 
  31 /* */
  32 #undef PRINT_MESSAGES
  33 /* */
  34 
  35 void Un_impl(void)
     /*  */
  36 {
  37   unsigned char byte1, FPU_modrm;
  38 
  39   RE_ENTRANT_CHECK_OFF
  40   byte1 = get_fs_byte((unsigned char *) FPU_ORIG_EIP);
  41   FPU_modrm = get_fs_byte(1 + (unsigned char *) FPU_ORIG_EIP);
  42 
  43   printk("Unimplemented FPU Opcode at eip=%p : %02x ",
  44          FPU_ORIG_EIP, byte1);
  45 
  46   if (FPU_modrm >= 0300)
  47     printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8, FPU_modrm & 7);
  48   else
  49     printk("/%d\n", (FPU_modrm >> 3) & 7);
  50   RE_ENTRANT_CHECK_ON
  51 
  52   EXCEPTION(EX_Invalid);
  53 
  54 }
  55 
  56 
  57 
  58 
  59 void emu_printall()
     /*  */
  60 {
  61   int i;
  62   static char *tag_desc[] = { "Valid", "Zero", "ERROR", "ERROR",
  63                               "DeNorm", "Inf", "NaN", "Empty" };
  64   unsigned char byte1, FPU_modrm;
  65 
  66   RE_ENTRANT_CHECK_OFF
  67   byte1 = get_fs_byte((unsigned char *) FPU_ORIG_EIP);
  68   FPU_modrm = get_fs_byte(1 + (unsigned char *) FPU_ORIG_EIP);
  69 
  70 #ifdef DEBUGGING
  71 if ( status_word & SW_B ) printk("SW: backward compatibility (=ES)\n");
  72 if ( status_word & SW_C3 ) printk("SW: condition bit 3\n");
  73 if ( status_word & SW_C2 ) printk("SW: condition bit 2\n");
  74 if ( status_word & SW_C1 ) printk("SW: condition bit 1\n");
  75 if ( status_word & SW_C0 ) printk("SW: condition bit 0\n");
  76 if ( status_word & SW_ES ) printk("SW: exception summary\n");
  77 if ( status_word & SW_SF ) printk("SW: stack fault\n");
  78 if ( status_word & SW_PE ) printk("SW: loss of precision\n");
  79 if ( status_word & SW_UE ) printk("SW: underflow\n");
  80 if ( status_word & SW_OE ) printk("SW: overflow\n");
  81 if ( status_word & SW_ZE ) printk("SW: divide by zero\n");
  82 if ( status_word & SW_DE ) printk("SW: denormalized operand\n");
  83 if ( status_word & SW_IE ) printk("SW: invalid operation\n");
  84 #endif DEBUGGING
  85 
  86   status_word = status_word & ~SW_TOP;
  87   status_word |= (top&7) << SW_TOPS;
  88 
  89   printk("At %p: %02x ", FPU_ORIG_EIP, byte1);
  90   if (FPU_modrm >= 0300)
  91     printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8, FPU_modrm & 7);
  92   else
  93     printk("/%d, mod=%d rm=%d\n",
  94            (FPU_modrm >> 3) & 7, (FPU_modrm >> 6) & 3, FPU_modrm & 7);
  95 
  96   printk(" SW: b=%d st=%d es=%d sf=%d cc=%d%d%d%d ef=%d%d%d%d%d%d\n",
  97          status_word & 0x8000 ? 1 : 0,   /* busy */
  98          (status_word & 0x3800) >> 11,   /* stack top pointer */
  99          status_word & 0x80 ? 1 : 0,     /* Error summary status */
 100          status_word & 0x40 ? 1 : 0,     /* Stack flag */
 101          status_word & SW_C3?1:0, status_word & SW_C2?1:0, /* cc */
 102          status_word & SW_C1?1:0, status_word & SW_C0?1:0, /* cc */
 103          status_word & SW_PE?1:0, status_word & SW_UE?1:0, /* exception fl */
 104          status_word & SW_OE?1:0, status_word & SW_ZE?1:0, /* exception fl */
 105          status_word & SW_DE?1:0, status_word & SW_IE?1:0); /* exception fl */
 106   
 107 printk(" CW: ic=%d rc=%d%d pc=%d%d iem=%d     ef=%d%d%d%d%d%d\n",
 108          control_word & 0x1000 ? 1 : 0,
 109          (control_word & 0x800) >> 11, (control_word & 0x400) >> 10,
 110          (control_word & 0x200) >> 9, (control_word & 0x100) >> 8,
 111          control_word & 0x80 ? 1 : 0,
 112          control_word & SW_PE?1:0, control_word & SW_UE?1:0, /* exception */
 113          control_word & SW_OE?1:0, control_word & SW_ZE?1:0, /* exception */
 114          control_word & SW_DE?1:0, control_word & SW_IE?1:0); /* exception */
 115 
 116   for ( i = 0; i < 8; i++ )
 117     {
 118       FPU_REG *r = &st(i);
 119       switch (r->tag)
 120         {
 121         case TW_Empty:
 122           continue;
 123           break;
 124         case TW_Zero:
 125           printk("st(%d)  %c .0000 0000 0000 0000         ",
 126                  i, r->sign ? '-' : '+');
 127           break;
 128         case TW_Valid:
 129         case TW_NaN:
 130         case TW_Denormal:
 131         case TW_Infinity:
 132           printk("st(%d)  %c .%04x %04x %04x %04x e%+-6d ", i,
 133                  r->sign ? '-' : '+',
 134                  (long)(r->sigh >> 16),
 135                  (long)(r->sigh & 0xFFFF),
 136                  (long)(r->sigl >> 16),
 137                  (long)(r->sigl & 0xFFFF),
 138                  r->exp - EXP_BIAS + 1);
 139           break;
 140         default:
 141           printk("Whoops! Error in errors.c      ");
 142           break;
 143         }
 144       printk("%s\n", tag_desc[(int) (unsigned) r->tag]);
 145     }
 146 
 147   printk("[data] %c .%04x %04x %04x %04x e%+-6d ",
 148          FPU_loaded_data.sign ? '-' : '+',
 149          (long)(FPU_loaded_data.sigh >> 16),
 150          (long)(FPU_loaded_data.sigh & 0xFFFF),
 151          (long)(FPU_loaded_data.sigl >> 16),
 152          (long)(FPU_loaded_data.sigl & 0xFFFF),
 153          FPU_loaded_data.exp - EXP_BIAS + 1);
 154   printk("%s\n", tag_desc[(int) (unsigned) FPU_loaded_data.tag]);
 155   RE_ENTRANT_CHECK_ON
 156 
 157 }
 158 
 159 static struct {
 160   int type;
 161   char *name;
 162 } exception_names[] = {
 163   { EX_StackOver, "stack overflow" },
 164   { EX_StackUnder, "stack underflow" },
 165   { EX_Precision, "loss of precision" },
 166   { EX_Underflow, "underflow" },
 167   { EX_Overflow, "overflow" },
 168   { EX_ZeroDiv, "divide by zero" },
 169   { EX_Denormal, "denormalized operand" },
 170   { EX_Invalid, "invalid operation" },
 171   { EX_INTERNAL, "INTERNAL BUG in "FPU_VERSION },
 172   { 0, NULL }
 173 };
 174 
 175 /*
 176  EX_INTERNAL is always given with a code which indicates where the
 177  error was detected.
 178 
 179  Internal error types:
 180        0x14   in e14.c
 181        0x1nn  in a *.c file:
 182               0x101  in reg_add_sub.c
 183               0x102  in reg_mul.c
 184               0x103  in poly_sin.c
 185               0x104  in poly_tan.c
 186               0x105  in reg_mul.c
 187               0x106  in reg_mov.c
 188               0x107  in fpu_trig.c
 189               0x108  in reg_compare.c
 190               0x109  in reg_compare.c
 191               0x110  in reg_add_sub.c
 192               0x111  in interface.c
 193               0x112  in fpu_trig.c
 194               0x113  in reg_add_sub.c
 195               0x114  in reg_ld_str.c
 196               0x115  in fpu_trig.c
 197               0x116  in fpu_trig.c
 198               0x117  in fpu_trig.c
 199               0x118  in fpu_trig.c
 200               0x119  in fpu_trig.c
 201               0x120  in poly_atan.c
 202               0x121  in reg_compare.c
 203               0x122  in reg_compare.c
 204               0x123  in reg_compare.c
 205        0x2nn  in an *.s file:
 206               0x201  in reg_u_add.S
 207               0x202  in reg_u_div.S
 208               0x203  in reg_u_div.S
 209               0x204  in reg_u_div.S
 210               0x205  in reg_u_mul.S
 211               0x206  in reg_u_sub.S
 212               0x207  in wm_sqrt.S
 213               0x208  in reg_div.S
 214               0x209  in reg_u_sub.S
 215               0x210  in reg_u_sub.S
 216               0x211  in reg_u_sub.S
 217               0x212  in reg_u_sub.S
 218  */
 219 
 220 void exception(int n)
     /*  */
 221 {
 222   int i, int_type;
 223 
 224   int_type = 0;         /* Needed only to stop compiler warnings */
 225   if ( n & EX_INTERNAL )
 226     {
 227       int_type = n - EX_INTERNAL;
 228       n = EX_INTERNAL;
 229       /* Set lots of exception bits! */
 230       status_word |= (0x3f | EX_ErrorSummary | FPU_BUSY);
 231     }
 232   else
 233     {
 234       /* Set the corresponding exception bit */
 235       status_word |= (n | EX_ErrorSummary | FPU_BUSY);
 236       if (n == EX_StackUnder)    /* Stack underflow */
 237         /* This bit distinguishes over- from underflow */
 238         status_word &= ~SW_C1;
 239     }
 240 
 241   RE_ENTRANT_CHECK_OFF
 242   if ( (~control_word & n & CW_EXM) || (n == EX_INTERNAL) )
 243     {
 244 #ifdef PRINT_MESSAGES
 245       /* My message from the sponsor */
 246       printk(FPU_VERSION" "__DATE__" (C) W. Metzenthen.\r\n");
 247 #endif PRINT_MESSAGES
 248       
 249       /* Get a name string for error reporting */
 250       for (i=0; exception_names[i].type; i++)
 251         if (exception_names[i].type == n)
 252           break;
 253       
 254       if (exception_names[i].type)
 255         {
 256 #ifdef PRINT_MESSAGES
 257           printk("FP Exception: %s!\n", exception_names[i].name);
 258 #endif PRINT_MESSAGES
 259         }
 260       else
 261         printk("FP emulator: Unknown Exception: 0x%04x!\n", n);
 262       
 263       if ( n == EX_INTERNAL )
 264         {
 265           printk("FP emulator: Internal error type 0x%04x\n", int_type);
 266           emu_printall();
 267         }
 268 #ifdef PRINT_MESSAGES
 269       else
 270         emu_printall();
 271 #endif PRINT_MESSAGES
 272 
 273       send_sig(SIGFPE, current, 1);
 274     }
 275   RE_ENTRANT_CHECK_ON
 276 
 277 #ifdef __DEBUG__
 278   math_abort(FPU_info,SIGFPE);
 279 #endif __DEBUG__
 280 
 281   /* Cause the look-ahead mechanism to terminate */
 282   FPU_lookahead = 0;
 283 }
 284 
 285 
 286 /* 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   x = a;
 292   if (a->tag == TW_NaN)
 293     {
 294       if (b->tag == TW_NaN)
 295         {
 296           /* find the "larger" */
 297           if ( *(long long *)&(a->sigl) < *(long long *)&(b->sigl) )
 298             x = b;
 299         }
 300       /* else return the quiet version of the NaN in a */
 301     }
 302   else if (b->tag == TW_NaN)
 303     {
 304       x = b;
 305     }
 306 #ifdef PARANOID
 307   else
 308     {
 309       EXCEPTION(EX_INTERNAL|0x113);
 310       x = &CONST_QNaN;
 311     }
 312 #endif PARANOID
 313   
 314   if ( control_word & EX_Invalid )
 315     {
 316       /* The masked response */
 317       reg_move(x, dest);
 318       /* ensure a Quiet NaN */
 319       dest->sigh |= 0x40000000;
 320     }
 321 
 322   EXCEPTION(EX_Invalid);
 323   
 324   return;
 325 }
 326 
 327 /* Invalid arith operation on valid registers */
 328 void arith_invalid(FPU_REG *dest)
     /*  */
 329 {
 330   
 331   if ( control_word & EX_Invalid )
 332     {
 333       /* The masked response */
 334       reg_move(&CONST_QNaN, dest);
 335     }
 336 
 337   EXCEPTION(EX_Invalid);
 338   
 339   return;
 340 
 341 }
 342 
 343 
 344 /* Divide a finite number by zero */
 345 void divide_by_zero(int sign, FPU_REG *dest)
     /*  */
 346 {
 347 
 348   if ( control_word & EX_ZeroDiv )
 349     {
 350       /* The masked response */
 351       reg_move(&CONST_INF, dest);
 352       dest->sign = (unsigned char)sign;
 353     }
 354  
 355   EXCEPTION(EX_ZeroDiv);
 356 
 357   return;
 358 
 359 }
 360 
 361 
 362 void arith_overflow(FPU_REG *dest)
     /*  */
 363 {
 364 
 365   if ( control_word & EX_Overflow )
 366     {
 367       char sign;
 368       /* The masked response */
 369       sign = dest->sign;
 370       reg_move(&CONST_INF, dest);
 371       dest->sign = sign;
 372     }
 373   else
 374     {
 375       /* Subtract the magic number from the exponent */
 376       dest->exp -= (3 * (1 << 13));
 377     }
 378 
 379   EXCEPTION(EX_Overflow);
 380 
 381   return;
 382 
 383 }
 384 
 385 
 386 void arith_underflow(FPU_REG *dest)
     /*  */
 387 {
 388 
 389   if ( control_word & EX_Underflow )
 390     {
 391       /* The masked response */
 392       if ( dest->exp <= EXP_UNDER - 63 )
 393         reg_move(&CONST_Z, dest);
 394     }
 395   else
 396     {
 397       /* Add the magic number to the exponent */
 398       dest->exp += (3 * (1 << 13));
 399     }
 400 
 401   EXCEPTION(EX_Underflow);
 402 
 403   return;
 404 }
 405 
 406 
 407 void stack_overflow(void)
     /*  */
 408 {
 409 
 410  if ( control_word & EX_Invalid )
 411     {
 412       /* The masked response */
 413       top--;
 414       reg_move(&CONST_QNaN, FPU_st0_ptr = &st(0));
 415     }
 416 
 417   EXCEPTION(EX_StackOver);
 418 
 419   return;
 420 
 421 }
 422 
 423 
 424 void stack_underflow(void)
     /*  */
 425 {
 426 
 427  if ( control_word & EX_Invalid )
 428     {
 429       /* The masked response */
 430       reg_move(&CONST_QNaN, FPU_st0_ptr);
 431     }
 432 
 433   EXCEPTION(EX_StackUnder);
 434 
 435   return;
 436 
 437 }
 438
/* */
root/kernel/FPU-emu/errors.c

DEFINITIONS
