libffi/src/mips/ffi.c

   1 /* -----------------------------------------------------------------------
   2    ffi.c - Copyright (c) 1996 Cygnus Solutions
   3
   4    MIPS Foreign Function Interface
   5
   6    Permission is hereby granted, free of charge, to any person obtaining
   7    a copy of this software and associated documentation files (the
   8    ``Software''), to deal in the Software without restriction, including
   9    without limitation the rights to use, copy, modify, merge, publish,
  10    distribute, sublicense, and/or sell copies of the Software, and to
  11    permit persons to whom the Software is furnished to do so, subject to
  12    the following conditions:
  13
  14    The above copyright notice and this permission notice shall be included
  15    in all copies or substantial portions of the Software.
  16
  17    THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  19    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  20    IN NO EVENT SHALL CYGNUS SOLUTIONS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21    OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22    ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23    OTHER DEALINGS IN THE SOFTWARE.
  24    ----------------------------------------------------------------------- */
  25
  26 #include <sgidefs.h>
  27 #include <ffi.h>
  28 #include <ffi_common.h>
  29
  30 #include <stdlib.h>
  31
  32 #if _MIPS_SIM == _MIPS_SIM_NABI32
  33 #define FIX_ARGP \
  34 FFI_ASSERT(argp <= &stack[bytes]); \
  35 if (argp == &stack[bytes]) \
  36 { \
  37   argp = stack; \
  38   ffi_stop_here(); \
  39 }
  40 #else
  41 #define FIX_ARGP
  42 #endif
  43
  44
  45 /* ffi_prep_args is called by the assembly routine once stack space
  46    has been allocated for the function's arguments */
  47
  48 static void ffi_prep_args(char *stack,
  49                           extended_cif *ecif,
  50                           int bytes,
  51                           int flags)
  52 {
  53   register int i;
  54   register void **p_argv;
  55   register char *argp;
  56   register ffi_type **p_arg;
  57
  58 #if _MIPS_SIM == _MIPS_SIM_NABI32
  59   /* If more than 8 double words are used, the remainder go
  60      on the stack. We reorder stuff on the stack here to
  61      support this easily. */
  62   if (bytes > 8 * SIZEOF_ARG)
  63     argp = &stack[bytes - (8 * SIZEOF_ARG)];
  64   else
  65     argp = stack;
  66 #else
  67   argp = stack;
  68 #endif
  69
  70   memset(stack, 0, bytes);
  71
  72 #if _MIPS_SIM == _MIPS_SIM_NABI32
  73   if ( ecif->cif->rstruct_flag != 0 )
  74 #else
  75   if ( ecif->cif->rtype->type == FFI_TYPE_STRUCT )
  76 #endif
  77     {
  78       *(SLOT_TYPE_UNSIGNED *) argp = (SLOT_TYPE_UNSIGNED) ecif->rvalue;
  79       argp += sizeof(SLOT_TYPE_UNSIGNED);
  80       FIX_ARGP;
  81     }
  82
  83   p_argv = ecif->avalue;
  84
  85   for (i = ecif->cif->nargs, p_arg = ecif->cif->arg_types; i; i--, p_arg++)
  86     {
  87       size_t z;
  88
  89       /* Align if necessary */
  90       if (((*p_arg)->alignment - 1) & (unsigned) argp) {
  91         argp = (char *) ALIGN(argp, (*p_arg)->alignment);
  92         FIX_ARGP;
  93       }
  94
  95 #if _MIPS_SIM == _MIPS_SIM_ABI32
  96 #define OFFSET 0
  97 #else
  98 #define OFFSET sizeof(int)
  99 #endif
 100
 101           z = (*p_arg)->size;
 102           if (z < sizeof(SLOT_TYPE_UNSIGNED))
 103             {
 104               z = sizeof(SLOT_TYPE_UNSIGNED);
 105
 106               switch ((*p_arg)->type)
 107                 {
 108                 case FFI_TYPE_SINT8:
 109                   *(SINT32 *) &argp[OFFSET] = (SINT32)*(SINT8 *)(* p_argv);
 110                   break;
 111
 112                 case FFI_TYPE_UINT8:
 113                   *(UINT32 *) &argp[OFFSET] = (UINT32)*(UINT8 *)(* p_argv);
 114                   break;
 115
 116                 case FFI_TYPE_SINT16:
 117                   *(SINT32 *) &argp[OFFSET] = (SINT32)*(SINT16 *)(* p_argv);
 118                   break;
 119
 120                 case FFI_TYPE_UINT16:
 121                   *(UINT32 *) &argp[OFFSET] = (UINT32)*(UINT16 *)(* p_argv);
 122                   break;
 123
 124                 case FFI_TYPE_SINT32:
 125                   *(SINT32 *) &argp[OFFSET] = (SINT32)*(SINT32 *)(* p_argv);
 126                   break;
 127
 128                 case FFI_TYPE_UINT32:
 129                 case FFI_TYPE_POINTER:
 130                   *(UINT32 *) &argp[OFFSET] = (UINT32)*(UINT32 *)(* p_argv);
 131                   break;
 132
 133                   /* This can only happen with 64bit slots */
 134                 case FFI_TYPE_FLOAT:
 135                   *(float *) argp = *(float *)(* p_argv);
 136                   break;
 137
 138                   /* Handle small structures */
 139                 case FFI_TYPE_STRUCT:
 140                   memcpy(argp, *p_argv, (*p_arg)->size);
 141                   break;
 142
 143                 default:
 144                   FFI_ASSERT(0);
 145                 }
 146             }
 147           else
 148             {
 149 #if _MIPS_SIM == _MIPS_SIM_ABI32
 150               memcpy(argp, *p_argv, z);
 151 #else
 152               {
 153                 unsigned end = (unsigned) argp+z;
 154                 unsigned cap = (unsigned) stack+bytes;
 155
 156                 /* Check if the data will fit within the register
 157                    space. Handle it if it doesn't. */
 158
 159                 if (end <= cap)
 160                   memcpy(argp, *p_argv, z);
 161                 else
 162                   {
 163                     unsigned portion = end - cap;
 164
 165                     memcpy(argp, *p_argv, portion);
 166                     argp = stack;
 167                     memcpy(argp,
 168                            (void*)((unsigned)(*p_argv)+portion), z - portion);
 169                   }
 170               }
 171 #endif
 172             }
 173           p_argv++;
 174           argp += z;
 175           FIX_ARGP;
 176     }
 177
 178   return;
 179 }
 180
 181 #if _MIPS_SIM == _MIPS_SIM_NABI32
 182
 183 /* The n32 spec says that if "a chunk consists solely of a double
 184    float field (but not a double, which is part of a union), it
 185    is passed in a floating point register. Any other chunk is
 186    passed in an integer register". This code traverses structure
 187    definitions and generates the appropriate flags. */
 188
 189 unsigned calc_n32_struct_flags(ffi_type *arg, unsigned *shift)
 190 {
 191   unsigned flags = 0;
 192   unsigned index = 0;
 193
 194   ffi_type *e;
 195
 196   while (e = arg->elements[index])
 197     {
 198       if (e->type == FFI_TYPE_DOUBLE)
 199         {
 200           flags += (FFI_TYPE_DOUBLE << *shift);
 201           *shift += FFI_FLAG_BITS;
 202         }
 203       else if (e->type == FFI_TYPE_STRUCT)
 204           flags += calc_n32_struct_flags(e, shift);
 205       else
 206         *shift += FFI_FLAG_BITS;
 207
 208       index++;
 209     }
 210
 211   return flags;
 212 }
 213
 214 unsigned calc_n32_return_struct_flags(ffi_type *arg)
 215 {
 216   unsigned flags = 0;
 217   unsigned index = 0;
 218   unsigned small = FFI_TYPE_SMALLSTRUCT;
 219   ffi_type *e;
 220
 221   /* Returning structures under n32 is a tricky thing.
 222      A struct with only one or two floating point fields
 223      is returned in $f0 (and $f2 if necessary). Any other
 224      struct results at most 128 bits are returned in $2
 225      (the first 64 bits) and $3 (remainder, if necessary).
 226      Larger structs are handled normally. */
 227
 228   if (arg->size > 16)
 229     return 0;
 230
 231   if (arg->size > 8)
 232     small = FFI_TYPE_SMALLSTRUCT2;
 233
 234   e = arg->elements[0];
 235   if (e->type == FFI_TYPE_DOUBLE)
 236     flags = FFI_TYPE_DOUBLE << FFI_FLAG_BITS;
 237   else if (e->type == FFI_TYPE_FLOAT)
 238     flags = FFI_TYPE_FLOAT << FFI_FLAG_BITS;
 239
 240   if (flags && (e = arg->elements[1]))
 241     {
 242       if (e->type == FFI_TYPE_DOUBLE)
 243         flags += FFI_TYPE_DOUBLE;
 244       else if (e->type == FFI_TYPE_FLOAT)
 245         flags += FFI_TYPE_FLOAT;
 246       else
 247         return small;
 248
 249       if (flags && (arg->elements[2]))
 250         {
 251           /* There are three arguments and the first two are
 252              floats! This must be passed the old way. */
 253           return small;
 254         }
 255     }
 256   else
 257     if (!flags)
 258       return small;
 259
 260   return flags;
 261 }
 262
 263 #endif
 264
 265 /* Perform machine dependent cif processing */
 266 ffi_status ffi_prep_cif_machdep(ffi_cif *cif)
 267 {
 268   cif->flags = 0;
 269
 270 #if _MIPS_SIM == _MIPS_SIM_ABI32
 271   /* Set the flags necessary for O32 processing */
 272
 273   if (cif->rtype->type != FFI_TYPE_STRUCT)
 274     {
 275       if (cif->nargs > 0)
 276         {
 277           switch ((cif->arg_types)[0]->type)
 278             {
 279             case FFI_TYPE_FLOAT:
 280             case FFI_TYPE_DOUBLE:
 281               cif->flags += (cif->arg_types)[0]->type;
 282               break;
 283
 284             default:
 285               break;
 286             }
 287
 288           if (cif->nargs > 1)
 289             {
 290               /* Only handle the second argument if the first
 291                  is a float or double. */
 292               if (cif->flags)
 293                 {
 294                   switch ((cif->arg_types)[1]->type)
 295                     {
 296                     case FFI_TYPE_FLOAT:
 297                     case FFI_TYPE_DOUBLE:
 298                       cif->flags += (cif->arg_types)[1]->type << FFI_FLAG_BITS;
 299                       break;
 300
 301                     default:
 302                       break;
 303                     }
 304                 }
 305             }
 306         }
 307     }
 308
 309   /* Set the return type flag */
 310   switch (cif->rtype->type)
 311     {
 312     case FFI_TYPE_VOID:
 313     case FFI_TYPE_STRUCT:
 314     case FFI_TYPE_FLOAT:
 315     case FFI_TYPE_DOUBLE:
 316       cif->flags += cif->rtype->type << (FFI_FLAG_BITS * 2);
 317       break;
 318
 319     default:
 320       cif->flags += FFI_TYPE_INT << (FFI_FLAG_BITS * 2);
 321       break;
 322     }
 323 #endif
 324
 325 #if _MIPS_SIM == _MIPS_SIM_NABI32
 326   /* Set the flags necessary for N32 processing */
 327   {
 328     unsigned shift = 0;
 329     unsigned count = (cif->nargs < 8) ? cif->nargs : 8;
 330     unsigned index = 0;
 331
 332     unsigned struct_flags = 0;
 333
 334     if (cif->rtype->type == FFI_TYPE_STRUCT)
 335       {
 336         struct_flags = calc_n32_return_struct_flags(cif->rtype);
 337
 338         if (struct_flags == 0)
 339           {
 340             /* This means that the structure is being passed as
 341                a hidden argument */
 342
 343             shift = FFI_FLAG_BITS;
 344             count = (cif->nargs < 7) ? cif->nargs : 7;
 345
 346             cif->rstruct_flag = !0;
 347           }
 348         else
 349             cif->rstruct_flag = 0;
 350       }
 351     else
 352       cif->rstruct_flag = 0;
 353
 354     while (count-- > 0)
 355       {
 356         switch ((cif->arg_types)[index]->type)
 357           {
 358           case FFI_TYPE_FLOAT:
 359           case FFI_TYPE_DOUBLE:
 360             cif->flags += ((cif->arg_types)[index]->type << shift);
 361             shift += FFI_FLAG_BITS;
 362             break;
 363
 364           case FFI_TYPE_STRUCT:
 365             cif->flags += calc_n32_struct_flags((cif->arg_types)[index],
 366                                                 &shift);
 367             break;
 368
 369           default:
 370             shift += FFI_FLAG_BITS;
 371           }
 372
 373         index++;
 374       }
 375
 376   /* Set the return type flag */
 377     switch (cif->rtype->type)
 378       {
 379       case FFI_TYPE_STRUCT:
 380         {
 381           if (struct_flags == 0)
 382             {
 383               /* The structure is returned through a hidden
 384                  first argument. Do nothing, 'cause FFI_TYPE_VOID
 385                  is 0 */
 386             }
 387           else
 388             {
 389               /* The structure is returned via some tricky
 390                  mechanism */
 391               cif->flags += FFI_TYPE_STRUCT << (FFI_FLAG_BITS * 8);
 392               cif->flags += struct_flags << (4 + (FFI_FLAG_BITS * 8));
 393             }
 394           break;
 395         }
 396
 397       case FFI_TYPE_VOID:
 398         /* Do nothing, 'cause FFI_TYPE_VOID is 0 */
 399         break;
 400
 401       case FFI_TYPE_FLOAT:
 402       case FFI_TYPE_DOUBLE:
 403         cif->flags += cif->rtype->type << (FFI_FLAG_BITS * 8);
 404         break;
 405
 406       default:
 407         cif->flags += FFI_TYPE_INT << (FFI_FLAG_BITS * 8);
 408         break;
 409       }
 410   }
 411 #endif
 412
 413   return FFI_OK;
 414 }
 415
 416 /* Low level routine for calling O32 functions */
 417 extern int ffi_call_O32(void (*)(char *, extended_cif *, int, int),
 418                         extended_cif *, unsigned,
 419                         unsigned, unsigned *, void (*)());
 420
 421 /* Low level routine for calling N32 functions */
 422 extern int ffi_call_N32(void (*)(char *, extended_cif *, int, int),
 423                         extended_cif *, unsigned,
 424                         unsigned, unsigned *, void (*)());
 425
 426 void ffi_call(ffi_cif *cif, void (*fn)(), void *rvalue, void **avalue)
 427 {
 428   extended_cif ecif;
 429
 430   ecif.cif = cif;
 431   ecif.avalue = avalue;
 432
 433   /* If the return value is a struct and we don't have a return */
 434   /* value address then we need to make one                     */
 435
 436   if ((rvalue == NULL) &&
 437       (cif->rtype->type == FFI_TYPE_STRUCT))
 438     ecif.rvalue = alloca(cif->rtype->size);
 439   else
 440     ecif.rvalue = rvalue;
 441
 442   switch (cif->abi)
 443     {
 444 #if _MIPS_SIM == _MIPS_SIM_ABI32
 445     case FFI_O32:
 446       ffi_call_O32(ffi_prep_args, &ecif, cif->bytes,
 447                    cif->flags, ecif.rvalue, fn);
 448       break;
 449 #endif
 450
 451 #if _MIPS_SIM == _MIPS_SIM_NABI32
 452     case FFI_N32:
 453       ffi_call_N32(ffi_prep_args, &ecif, cif->bytes,
 454                    cif->flags, ecif.rvalue, fn);
 455       break;
 456 #endif
 457
 458     default:
 459       FFI_ASSERT(0);
 460       break;
 461     }
 462 }