thunk.c

   1 /*
   2  *  Generic thunking code to convert data between host and target CPU
   3  *
   4  *  Copyright (c) 2003 Fabrice Bellard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #include <stdlib.h>
  21 #include <stdio.h>
  22 #include <stdarg.h>
  23
  24 #include "qemu.h"
  25 #include "thunk.h"
  26
  27 //#define DEBUG
  28
  29 #define MAX_STRUCTS 128
  30
  31 /* XXX: make it dynamic */
  32 StructEntry struct_entries[MAX_STRUCTS];
  33
  34 static inline const argtype *thunk_type_next(const argtype *type_ptr)
  35 {
  36     int type;
  37
  38     type = *type_ptr++;
  39     switch(type) {
  40     case TYPE_CHAR:
  41     case TYPE_SHORT:
  42     case TYPE_INT:
  43     case TYPE_LONGLONG:
  44     case TYPE_ULONGLONG:
  45     case TYPE_LONG:
  46     case TYPE_ULONG:
  47     case TYPE_PTRVOID:
  48         return type_ptr;
  49     case TYPE_PTR:
  50         return thunk_type_next(type_ptr);
  51     case TYPE_ARRAY:
  52         return thunk_type_next(type_ptr + 1);
  53     case TYPE_STRUCT:
  54         return type_ptr + 1;
  55     default:
  56         return NULL;
  57     }
  58 }
  59
  60 void thunk_register_struct(int id, const char *name, const argtype *types)
  61 {
  62     const argtype *type_ptr;
  63     StructEntry *se;
  64     int nb_fields, offset, max_align, align, size, i, j;
  65
  66     se = struct_entries + id;
  67
  68     /* first we count the number of fields */
  69     type_ptr = types;
  70     nb_fields = 0;
  71     while (*type_ptr != TYPE_NULL) {
  72         type_ptr = thunk_type_next(type_ptr);
  73         nb_fields++;
  74     }
  75     se->field_types = types;
  76     se->nb_fields = nb_fields;
  77     se->name = name;
  78 #ifdef DEBUG
  79     printf("struct %s: id=%d nb_fields=%d\n",
  80            se->name, id, se->nb_fields);
  81 #endif
  82     /* now we can alloc the data */
  83
  84     for(i = 0;i < 2; i++) {
  85         offset = 0;
  86         max_align = 1;
  87         se->field_offsets[i] = malloc(nb_fields * sizeof(int));
  88         type_ptr = se->field_types;
  89         for(j = 0;j < nb_fields; j++) {
  90             size = thunk_type_size(type_ptr, i);
  91             align = thunk_type_align(type_ptr, i);
  92             offset = (offset + align - 1) & ~(align - 1);
  93             se->field_offsets[i][j] = offset;
  94             offset += size;
  95             if (align > max_align)
  96                 max_align = align;
  97             type_ptr = thunk_type_next(type_ptr);
  98         }
  99         offset = (offset + max_align - 1) & ~(max_align - 1);
 100         se->size[i] = offset;
 101         se->align[i] = max_align;
 102 #ifdef DEBUG
 103         printf("%s: size=%d align=%d\n",
 104                i == THUNK_HOST ? "host" : "target", offset, max_align);
 105 #endif
 106     }
 107 }
 108
 109 void thunk_register_struct_direct(int id, const char *name, StructEntry *se1)
 110 {
 111     StructEntry *se;
 112     se = struct_entries + id;
 113     *se = *se1;
 114     se->name = name;
 115 }
 116
 117
 118 /* now we can define the main conversion functions */
 119 const argtype *thunk_convert(void *dst, const void *src,
 120                              const argtype *type_ptr, int to_host)
 121 {
 122     int type;
 123
 124     type = *type_ptr++;
 125     switch(type) {
 126     case TYPE_CHAR:
 127         *(uint8_t *)dst = *(uint8_t *)src;
 128         break;
 129     case TYPE_SHORT:
 130         *(uint16_t *)dst = tswap16(*(uint16_t *)src);
 131         break;
 132     case TYPE_INT:
 133         *(uint32_t *)dst = tswap32(*(uint32_t *)src);
 134         break;
 135     case TYPE_LONGLONG:
 136     case TYPE_ULONGLONG:
 137         *(uint64_t *)dst = tswap64(*(uint64_t *)src);
 138         break;
 139 #if HOST_LONG_BITS == 32 && TARGET_LONG_BITS == 32
 140     case TYPE_LONG:
 141     case TYPE_ULONG:
 142     case TYPE_PTRVOID:
 143         *(uint32_t *)dst = tswap32(*(uint32_t *)src);
 144         break;
 145 #elif HOST_LONG_BITS == 64 && TARGET_LONG_BITS == 32
 146     case TYPE_LONG:
 147     case TYPE_ULONG:
 148     case TYPE_PTRVOID:
 149         if (to_host) {
 150             *(uint64_t *)dst = tswap32(*(uint32_t *)src);
 151         } else {
 152             *(uint32_t *)dst = tswap32(*(uint64_t *)src & 0xffffffff);
 153         }
 154         break;
 155 #else
 156 #warning unsupported conversion
 157 #endif
 158     case TYPE_ARRAY:
 159         {
 160             int array_length, i, dst_size, src_size;
 161             const uint8_t *s;
 162             uint8_t  *d;
 163
 164             array_length = *type_ptr++;
 165             dst_size = thunk_type_size(type_ptr, to_host);
 166             src_size = thunk_type_size(type_ptr, 1 - to_host);
 167             d = dst;
 168             s = src;
 169             for(i = 0;i < array_length; i++) {
 170                 thunk_convert(d, s, type_ptr, to_host);
 171                 d += dst_size;
 172                 s += src_size;
 173             }
 174             type_ptr = thunk_type_next(type_ptr);
 175         }
 176         break;
 177     case TYPE_STRUCT:
 178         {
 179             int i;
 180             const StructEntry *se;
 181             const uint8_t *s;
 182             uint8_t  *d;
 183             const argtype *field_types;
 184             const int *dst_offsets, *src_offsets;
 185
 186             se = struct_entries + *type_ptr++;
 187             if (se->convert[0] != NULL) {
 188                 /* specific conversion is needed */
 189                 (*se->convert[to_host])(dst, src);
 190             } else {
 191                 /* standard struct conversion */
 192                 field_types = se->field_types;
 193                 dst_offsets = se->field_offsets[to_host];
 194                 src_offsets = se->field_offsets[1 - to_host];
 195                 d = dst;
 196                 s = src;
 197                 for(i = 0;i < se->nb_fields; i++) {
 198                     field_types = thunk_convert(d + dst_offsets[i],
 199                                                 s + src_offsets[i],
 200                                                 field_types, to_host);
 201                 }
 202             }
 203         }
 204         break;
 205     default:
 206         fprintf(stderr, "Invalid type 0x%x\n", type);
 207         break;
 208     }
 209     return type_ptr;
 210 }
 211
 212 /* from em86 */
 213
 214 /* Utility function: Table-driven functions to translate bitmasks
 215  * between X86 and Alpha formats...
 216  */
 217 unsigned int target_to_host_bitmask(unsigned int x86_mask,
 218                                     bitmask_transtbl * trans_tbl)
 219 {
 220     bitmask_transtbl *  btp;
 221     unsigned int        alpha_mask = 0;
 222
 223     for(btp = trans_tbl; btp->x86_mask && btp->alpha_mask; btp++) {
 224         if((x86_mask & btp->x86_mask) == btp->x86_bits) {
 225             alpha_mask |= btp->alpha_bits;
 226         }
 227     }
 228     return(alpha_mask);
 229 }
 230
 231 unsigned int host_to_target_bitmask(unsigned int alpha_mask,
 232                                     bitmask_transtbl * trans_tbl)
 233 {
 234     bitmask_transtbl *  btp;
 235     unsigned int        x86_mask = 0;
 236
 237     for(btp = trans_tbl; btp->x86_mask && btp->alpha_mask; btp++) {
 238         if((alpha_mask & btp->alpha_mask) == btp->alpha_bits) {
 239             x86_mask |= btp->x86_bits;
 240         }
 241     }
 242     return(x86_mask);
 243 }