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) 1992,1993                                                   |
   7  |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
   8  |                       Australia.  E-mail apm233m@vaxc.cc.monash.edu.au    |
   9  |                                                                           |
  10  |                                                                           |
  11  +---------------------------------------------------------------------------*/
  12 
  13 /*---------------------------------------------------------------------------+
  14  | Note:                                                                     |
  15  |    The file contains code which accesses user memory.                     |
  16  |    Emulator static data may change when user memory is accessed, due to   |
  17  |    other processes using the emulator while swapping is in progress.      |
  18  +---------------------------------------------------------------------------*/
  19 
  20 #include <linux/signal.h>
  21 
  22 #include <asm/segment.h>
  23 
  24 #include "fpu_system.h"
  25 #include "exception.h"
  26 #include "fpu_emu.h"
  27 #include "status_w.h"
  28 #include "control_w.h"
  29 #include "reg_constant.h"
  30 #include "version.h"
  31 
  32 /* */
  33 #undef PRINT_MESSAGES
  34 /* */
  35 
  36 void Un_impl(void)
     /*  */
  37 {
  38   unsigned char byte1, FPU_modrm;
  39 
  40   RE_ENTRANT_CHECK_OFF
  41   byte1 = get_fs_byte((unsigned char *) FPU_ORIG_EIP);
  42   FPU_modrm = get_fs_byte(1 + (unsigned char *) FPU_ORIG_EIP);
  43 
  44   printk("Unimplemented FPU Opcode at eip=%p : %02x ",
  45          FPU_ORIG_EIP, byte1);
  46 
  47   if (FPU_modrm >= 0300)
  48     printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8, FPU_modrm & 7);
  49   else
  50     printk("/%d\n", (FPU_modrm >> 3) & 7);
  51   RE_ENTRANT_CHECK_ON
  52 
  53   EXCEPTION(EX_Invalid);
  54 
  55 }
  56 
  57 
  58 
  59 
  60 void emu_printall()
     /*  */
  61 {
  62   int i;
  63   static char *tag_desc[] = { "Valid", "Zero", "ERROR", "ERROR",
  64                               "DeNorm", "Inf", "NaN", "Empty" };
  65   unsigned char byte1, FPU_modrm;
  66 
  67   RE_ENTRANT_CHECK_OFF
  68   byte1 = get_fs_byte((unsigned char *) FPU_ORIG_EIP);
  69   FPU_modrm = get_fs_byte(1 + (unsigned char *) FPU_ORIG_EIP);
  70 
  71 #ifdef DEBUGGING
  72 if ( status_word & SW_B ) printk("SW: backward compatibility (=ES)\n");
  73 if ( status_word & SW_C3 ) printk("SW: condition bit 3\n");
  74 if ( status_word & SW_C2 ) printk("SW: condition bit 2\n");
  75 if ( status_word & SW_C1 ) printk("SW: condition bit 1\n");
  76 if ( status_word & SW_C0 ) printk("SW: condition bit 0\n");
  77 if ( status_word & SW_ES ) printk("SW: exception summary\n");
  78 if ( status_word & SW_SF ) printk("SW: stack fault\n");
  79 if ( status_word & SW_PE ) printk("SW: loss of precision\n");
  80 if ( status_word & SW_UE ) printk("SW: underflow\n");
  81 if ( status_word & SW_OE ) printk("SW: overflow\n");
  82 if ( status_word & SW_ZE ) printk("SW: divide by zero\n");
  83 if ( status_word & SW_DE ) printk("SW: denormalized operand\n");
  84 if ( status_word & SW_IE ) printk("SW: invalid operation\n");
  85 #endif DEBUGGING
  86 
  87   status_word = status_word & ~SW_TOP;
  88   status_word |= (top&7) << SW_TOPS;
  89 
  90   printk("At %p: %02x ", FPU_ORIG_EIP, byte1);
  91   if (FPU_modrm >= 0300)
  92     printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8, FPU_modrm & 7);
  93   else
  94     printk("/%d, mod=%d rm=%d\n",
  95            (FPU_modrm >> 3) & 7, (FPU_modrm >> 6) & 3, FPU_modrm & 7);
  96 
  97   printk(" SW: b=%d st=%d es=%d sf=%d cc=%d%d%d%d ef=%d%d%d%d%d%d\n",
  98          status_word & 0x8000 ? 1 : 0,   /* busy */
  99          (status_word & 0x3800) >> 11,   /* stack top pointer */
 100          status_word & 0x80 ? 1 : 0,     /* Error summary status */
 101          status_word & 0x40 ? 1 : 0,     /* Stack flag */
 102          status_word & SW_C3?1:0, status_word & SW_C2?1:0, /* cc */
 103          status_word & SW_C1?1:0, status_word & SW_C0?1:0, /* cc */
 104          status_word & SW_PE?1:0, status_word & SW_UE?1:0, /* exception fl */
 105          status_word & SW_OE?1:0, status_word & SW_ZE?1:0, /* exception fl */
 106          status_word & SW_DE?1:0, status_word & SW_IE?1:0); /* exception fl */
 107   
 108 printk(" CW: ic=%d rc=%d%d pc=%d%d iem=%d     ef=%d%d%d%d%d%d\n",
 109          control_word & 0x1000 ? 1 : 0,
 110          (control_word & 0x800) >> 11, (control_word & 0x400) >> 10,
 111          (control_word & 0x200) >> 9, (control_word & 0x100) >> 8,
 112          control_word & 0x80 ? 1 : 0,
 113          control_word & SW_PE?1:0, control_word & SW_UE?1:0, /* exception */
 114          control_word & SW_OE?1:0, control_word & SW_ZE?1:0, /* exception */
 115          control_word & SW_DE?1:0, control_word & SW_IE?1:0); /* exception */
 116 
 117   for ( i = 0; i < 8; i++ )
 118     {
 119       FPU_REG *r = &st(i);
 120       switch (r->tag)
 121         {
 122         case TW_Empty:
 123           continue;
 124           break;
 125         case TW_Zero:
 126           printk("st(%d)  %c .0000 0000 0000 0000         ",
 127                  i, r->sign ? '-' : '+');
 128           break;
 129         case TW_Valid:
 130         case TW_NaN:
 131         case TW_Denormal:
 132         case TW_Infinity:
 133           printk("st(%d)  %c .%04x %04x %04x %04x e%+-6d ", i,
 134                  r->sign ? '-' : '+',
 135                  (long)(r->sigh >> 16),
 136                  (long)(r->sigh & 0xFFFF),
 137                  (long)(r->sigl >> 16),
 138                  (long)(r->sigl & 0xFFFF),
 139                  r->exp - EXP_BIAS + 1);
 140           break;
 141         default:
 142           printk("Whoops! Error in errors.c      ");
 143           break;
 144         }
 145       printk("%s\n", tag_desc[(int) (unsigned) r->tag]);
 146     }
 147 
 148   printk("[data] %c .%04x %04x %04x %04x e%+-6d ",
 149          FPU_loaded_data.sign ? '-' : '+',
 150          (long)(FPU_loaded_data.sigh >> 16),
 151          (long)(FPU_loaded_data.sigh & 0xFFFF),
 152          (long)(FPU_loaded_data.sigl >> 16),
 153          (long)(FPU_loaded_data.sigl & 0xFFFF),
 154          FPU_loaded_data.exp - EXP_BIAS + 1);
 155   printk("%s\n", tag_desc[(int) (unsigned) FPU_loaded_data.tag]);
 156   RE_ENTRANT_CHECK_ON
 157 
 158 }
 159 
 160 static struct {
 161   int type;
 162   char *name;
 163 } exception_names[] = {
 164   { EX_StackOver, "stack overflow" },
 165   { EX_StackUnder, "stack underflow" },
 166   { EX_Precision, "loss of precision" },
 167   { EX_Underflow, "underflow" },
 168   { EX_Overflow, "overflow" },
 169   { EX_ZeroDiv, "divide by zero" },
 170   { EX_Denormal, "denormalized operand" },
 171   { EX_Invalid, "invalid operation" },
 172   { EX_INTERNAL, "INTERNAL BUG in "FPU_VERSION },
 173   { 0, NULL }
 174 };
 175 
 176 /*
 177  EX_INTERNAL is always given with a code which indicates where the
 178  error was detected.
 179 
 180  Internal error types:
 181        0x14   in e14.c
 182        0x1nn  in a *.c file:
 183               0x101  in reg_add_sub.c
 184               0x102  in reg_mul.c
 185               0x103  in poly_sin.c
 186               0x104  in poly_tan.c
 187               0x105  in reg_mul.c
 188               0x106  in reg_mov.c
 189               0x107  in fpu_trig.c
 190               0x108  in reg_compare.c
 191               0x109  in reg_compare.c
 192               0x110  in reg_add_sub.c
 193               0x111  in interface.c
 194               0x112  in fpu_trig.c
 195               0x113  in reg_add_sub.c
 196               0x114  in reg_ld_str.c
 197               0x115  in fpu_trig.c
 198               0x116  in fpu_trig.c
 199               0x117  in fpu_trig.c
 200               0x118  in fpu_trig.c
 201               0x119  in fpu_trig.c
 202               0x120  in poly_atan.c
 203               0x121  in reg_compare.c
 204               0x122  in reg_compare.c
 205               0x123  in reg_compare.c
 206        0x2nn  in an *.s file:
 207               0x201  in reg_u_add.S
 208               0x202  in reg_u_div.S
 209               0x203  in reg_u_div.S
 210               0x204  in reg_u_div.S
 211               0x205  in reg_u_mul.S
 212               0x206  in reg_u_sub.S
 213               0x207  in wm_sqrt.S
 214               0x208  in reg_div.S
 215               0x209  in reg_u_sub.S
 216               0x210  in reg_u_sub.S
 217               0x211  in reg_u_sub.S
 218               0x212  in reg_u_sub.S
 219  */
 220 
 221 void exception(int n)
     /*  */
 222 {
 223   int i, int_type;
 224 
 225   int_type = 0;         /* Needed only to stop compiler warnings */
 226   if ( n & EX_INTERNAL )
 227     {
 228       int_type = n - EX_INTERNAL;
 229       n = EX_INTERNAL;
 230       /* Set lots of exception bits! */
 231       status_word |= (0x3f | EX_ErrorSummary | FPU_BUSY);
 232     }
 233   else
 234     {
 235       /* Set the corresponding exception bit */
 236       status_word |= (n | EX_ErrorSummary | FPU_BUSY);
 237       if (n == EX_StackUnder)    /* Stack underflow */
 238         /* This bit distinguishes over- from underflow */
 239         status_word &= ~SW_C1;
 240     }
 241 
 242   RE_ENTRANT_CHECK_OFF
 243   if ( (~control_word & n & CW_EXM) || (n == EX_INTERNAL) )
 244     {
 245 #ifdef PRINT_MESSAGES
 246       /* My message from the sponsor */
 247       printk(FPU_VERSION" "__DATE__" (C) W. Metzenthen.\n");
 248 #endif PRINT_MESSAGES
 249       
 250       /* Get a name string for error reporting */
 251       for (i=0; exception_names[i].type; i++)
 252         if (exception_names[i].type == n)
 253           break;
 254       
 255       if (exception_names[i].type)
 256         {
 257 #ifdef PRINT_MESSAGES
 258           printk("FP Exception: %s!\n", exception_names[i].name);
 259 #endif PRINT_MESSAGES
 260         }
 261       else
 262         printk("FP emulator: Unknown Exception: 0x%04x!\n", n);
 263       
 264       if ( n == EX_INTERNAL )
 265         {
 266           printk("FP emulator: Internal error type 0x%04x\n", int_type);
 267           emu_printall();
 268         }
 269 #ifdef PRINT_MESSAGES
 270       else
 271         emu_printall();
 272 #endif PRINT_MESSAGES
 273 
 274       send_sig(SIGFPE, current, 1);
 275     }
 276   RE_ENTRANT_CHECK_ON
 277 
 278 #ifdef __DEBUG__
 279   math_abort(FPU_info,SIGFPE);
 280 #endif __DEBUG__
 281 
 282   /* Cause the look-ahead mechanism to terminate */
 283   FPU_lookahead = 0;
 284 }
 285 
 286 
 287 /* Real operation attempted on two operands, one a NaN */
 288 void real_2op_NaN(FPU_REG *a, FPU_REG *b, FPU_REG *dest)
     /*  */
 289 {
 290   FPU_REG *x;
 291   
 292   x = a;
 293   if (a->tag == TW_NaN)
 294     {
 295       if (b->tag == TW_NaN)
 296         {
 297           /* find the "larger" */
 298           if ( *(long long *)&(a->sigl) < *(long long *)&(b->sigl) )
 299             x = b;
 300         }
 301       /* else return the quiet version of the NaN in a */
 302     }
 303   else if (b->tag == TW_NaN)
 304     {
 305       x = b;
 306     }
 307 #ifdef PARANOID
 308   else
 309     {
 310       EXCEPTION(EX_INTERNAL|0x113);
 311       x = &CONST_QNaN;
 312     }
 313 #endif PARANOID
 314   
 315   if ( control_word & EX_Invalid )
 316     {
 317       /* The masked response */
 318       reg_move(x, dest);
 319       /* ensure a Quiet NaN */
 320       dest->sigh |= 0x40000000;
 321     }
 322 
 323   EXCEPTION(EX_Invalid);
 324   
 325   return;
 326 }
 327 
 328 /* Invalid arith operation on valid registers */
 329 void arith_invalid(FPU_REG *dest)
     /*  */
 330 {
 331   
 332   if ( control_word & EX_Invalid )
 333     {
 334       /* The masked response */
 335       reg_move(&CONST_QNaN, dest);
 336     }
 337 
 338   EXCEPTION(EX_Invalid);
 339   
 340   return;
 341 
 342 }
 343 
 344 
 345 /* Divide a finite number by zero */
 346 void divide_by_zero(int sign, FPU_REG *dest)
     /*  */
 347 {
 348 
 349   if ( control_word & EX_ZeroDiv )
 350     {
 351       /* The masked response */
 352       reg_move(&CONST_INF, dest);
 353       dest->sign = (unsigned char)sign;
 354     }
 355  
 356   EXCEPTION(EX_ZeroDiv);
 357 
 358   return;
 359 
 360 }
 361 
 362 
 363 void arith_overflow(FPU_REG *dest)
     /*  */
 364 {
 365 
 366   if ( control_word & EX_Overflow )
 367     {
 368       char sign;
 369       /* The masked response */
 370       sign = dest->sign;
 371       reg_move(&CONST_INF, dest);
 372       dest->sign = sign;
 373     }
 374   else
 375     {
 376       /* Subtract the magic number from the exponent */
 377       dest->exp -= (3 * (1 << 13));
 378     }
 379 
 380   EXCEPTION(EX_Overflow);
 381 
 382   return;
 383 
 384 }
 385 
 386 
 387 void arith_underflow(FPU_REG *dest)
     /*  */
 388 {
 389 
 390   if ( control_word & EX_Underflow )
 391     {
 392       /* The masked response */
 393       if ( dest->exp <= EXP_UNDER - 63 )
 394         reg_move(&CONST_Z, dest);
 395     }
 396   else
 397     {
 398       /* Add the magic number to the exponent */
 399       dest->exp += (3 * (1 << 13));
 400     }
 401 
 402   EXCEPTION(EX_Underflow);
 403 
 404   return;
 405 }
 406 
 407 
 408 void stack_overflow(void)
     /*  */
 409 {
 410 
 411  if ( control_word & EX_Invalid )
 412     {
 413       /* The masked response */
 414       top--;
 415       reg_move(&CONST_QNaN, FPU_st0_ptr = &st(0));
 416     }
 417 
 418   EXCEPTION(EX_StackOver);
 419 
 420   return;
 421 
 422 }
 423 
 424 
 425 void stack_underflow(void)
     /*  */
 426 {
 427 
 428  if ( control_word & EX_Invalid )
 429     {
 430       /* The masked response */
 431       reg_move(&CONST_QNaN, FPU_st0_ptr);
 432     }
 433 
 434   EXCEPTION(EX_StackUnder);
 435 
 436   return;
 437 
 438 }
 439
/* */
root/kernel/FPU-emu/errors.c

DEFINITIONS
