qemu/thunk.c

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/*
* Generic thunking code to convert data between host and target CPU
*
* Copyright (c) 2003 Fabrice Bellard
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include "gemu.h"
#include "thunk.h"
//#define DEBUG
#define MAX_STRUCTS 128
/* XXX: make it dynamic */
static StructEntry struct_entries[MAX_STRUCTS];
static inline int thunk_type_size(const argtype *type_ptr, int is_host)
{
int type, size;
const StructEntry *se;
type = *type_ptr;
switch(type) {
case TYPE_CHAR:
return 1;
case TYPE_SHORT:
return 2;
case TYPE_INT:
return 4;
case TYPE_LONGLONG:
case TYPE_ULONGLONG:
return 8;
case TYPE_LONG:
case TYPE_ULONG:
case TYPE_PTRVOID:
case TYPE_PTR:
if (is_host) {
return HOST_LONG_SIZE;
} else {
return TARGET_LONG_SIZE;
}
break;
case TYPE_ARRAY:
size = type_ptr[1];
return size * thunk_type_size(type_ptr + 2, is_host);
case TYPE_STRUCT:
se = struct_entries + type_ptr[1];
return se->size[is_host];
default:
return -1;
}
}
static inline int thunk_type_align(const argtype *type_ptr, int is_host)
{
int type;
const StructEntry *se;
type = *type_ptr;
switch(type) {
case TYPE_CHAR:
return 1;
case TYPE_SHORT:
return 2;
case TYPE_INT:
return 4;
case TYPE_LONGLONG:
case TYPE_ULONGLONG:
return 8;
case TYPE_LONG:
case TYPE_ULONG:
case TYPE_PTRVOID:
case TYPE_PTR:
if (is_host) {
return HOST_LONG_SIZE;
} else {
return TARGET_LONG_SIZE;
}
break;
case TYPE_ARRAY:
return thunk_type_align(type_ptr + 2, is_host);
case TYPE_STRUCT:
se = struct_entries + type_ptr[1];
return se->align[is_host];
default:
return -1;
}
}
static inline const argtype *thunk_type_next(const argtype *type_ptr)
{
int type;
type = *type_ptr++;
switch(type) {
case TYPE_CHAR:
case TYPE_SHORT:
case TYPE_INT:
case TYPE_LONGLONG:
case TYPE_ULONGLONG:
case TYPE_LONG:
case TYPE_ULONG:
case TYPE_PTRVOID:
return type_ptr;
case TYPE_PTR:
return thunk_type_next(type_ptr);
case TYPE_ARRAY:
return thunk_type_next(type_ptr + 1);
case TYPE_STRUCT:
return type_ptr + 1;
default:
return NULL;
}
}
void thunk_register_struct(int id, const char *name, const argtype *types)
{
const argtype *type_ptr;
StructEntry *se;
int nb_fields, offset, max_align, align, size, i, j;
se = struct_entries + id;
/* first we count the number of fields */
type_ptr = types;
nb_fields = 0;
while (*type_ptr != TYPE_NULL) {
type_ptr = thunk_type_next(type_ptr);
nb_fields++;
}
se->field_types = types;
se->nb_fields = nb_fields;
se->name = name;
#ifdef DEBUG
printf("struct %s: id=%d nb_fields=%d\n",
se->name, id, se->nb_fields);
#endif
/* now we can alloc the data */
for(i = 0;i < 2; i++) {
offset = 0;
max_align = 1;
se->field_offsets[i] = malloc(nb_fields * sizeof(int));
type_ptr = se->field_types;
for(j = 0;j < nb_fields; j++) {
size = thunk_type_size(type_ptr, i);
align = thunk_type_align(type_ptr, i);
offset = (offset + align - 1) & ~(align - 1);
se->field_offsets[i][j] = offset;
offset += size;
if (align > max_align)
max_align = align;
}
offset = (offset + max_align - 1) & ~(max_align - 1);
se->size[i] = offset;
se->align[i] = max_align;
#ifdef DEBUG
printf("%s: size=%d align=%d\n",
i == THUNK_HOST ? "host" : "target", offset, max_align);
#endif
}
}
void thunk_register_struct_direct(int id, const char *name, StructEntry *se1)
{
StructEntry *se;
se = struct_entries + id;
*se = *se1;
se->name = name;
}
/* now we can define the main conversion functions */
const argtype *thunk_convert(void *dst, const void *src,
const argtype *type_ptr, int to_host)
{
int type;
type = *type_ptr++;
switch(type) {
case TYPE_CHAR:
*(uint8_t *)dst = *(uint8_t *)src;
break;
case TYPE_SHORT:
*(uint16_t *)dst = tswap16(*(uint16_t *)src);
break;
case TYPE_INT:
*(uint32_t *)dst = tswap32(*(uint32_t *)src);
break;
case TYPE_LONGLONG:
case TYPE_ULONGLONG:
*(uint64_t *)dst = tswap64(*(uint64_t *)src);
break;
#if HOST_LONG_BITS == 32 && TARGET_LONG_BITS == 32
case TYPE_LONG:
case TYPE_ULONG:
case TYPE_PTRVOID:
*(uint32_t *)dst = tswap32(*(uint32_t *)src);
break;
#elif HOST_LONG_BITS == 64 && TARGET_LONG_BITS == 32
case TYPE_LONG:
case TYPE_ULONG:
case TYPE_PTRVOID:
if (target_to_host) {
*(uint64_t *)dst = tswap32(*(uint32_t *)src);
} else {
*(uint32_t *)dst = tswap32(*(uint64_t *)src & 0xffffffff);
}
break;
#else
#error unsupported conversion
#endif
case TYPE_ARRAY:
{
int array_length, i, dst_size, src_size;
const uint8_t *s;
uint8_t *d;
array_length = *type_ptr++;
dst_size = thunk_type_size(type_ptr, to_host);
src_size = thunk_type_size(type_ptr, 1 - to_host);
d = dst;
s = src;
for(i = 0;i < array_length; i++) {
thunk_convert(d, s, type_ptr, to_host);
d += dst_size;
s += src_size;
}
type_ptr = thunk_type_next(type_ptr);
}
break;
case TYPE_STRUCT:
{
int i;
const StructEntry *se;
const uint8_t *s;
uint8_t *d;
const argtype *field_types;
const int *dst_offsets, *src_offsets;
se = struct_entries + *type_ptr++;
if (se->convert[0] != NULL) {
/* specific conversion is needed */
(*se->convert[to_host])(dst, src);
} else {
/* standard struct conversion */
field_types = se->field_types;
dst_offsets = se->field_offsets[to_host];
src_offsets = se->field_offsets[1 - to_host];
d = dst;
s = src;
for(i = 0;i < se->nb_fields; i++) {
field_types = thunk_convert(d + dst_offsets[i],
s + src_offsets[i],
field_types, to_host);
}
}
}
break;
default:
fprintf(stderr, "Invalid type 0x%x\n", type);
break;
}
return type_ptr;
}
/* from em86 */
/* Utility function: Table-driven functions to translate bitmasks
* between X86 and Alpha formats...
*/
unsigned int target_to_host_bitmask(unsigned int x86_mask,
bitmask_transtbl * trans_tbl)
{
bitmask_transtbl * btp;
unsigned int alpha_mask = 0;
for(btp = trans_tbl; btp->x86_mask && btp->alpha_mask; btp++) {
if((x86_mask & btp->x86_mask) == btp->x86_bits) {
alpha_mask |= btp->alpha_bits;
}
}
return(alpha_mask);
}
unsigned int host_to_target_bitmask(unsigned int alpha_mask,
bitmask_transtbl * trans_tbl)
{
bitmask_transtbl * btp;
unsigned int x86_mask = 0;
for(btp = trans_tbl; btp->x86_mask && btp->alpha_mask; btp++) {
if((alpha_mask & btp->alpha_mask) == btp->alpha_bits) {
x86_mask |= btp->x86_mask;
}
}
return(x86_mask);
}