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/* sp.c: Routines for handling .sp snapshots
Copyright (c) 1998,2003 Philip Kendall
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.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
Author contact information:
E-mail: philip-fuse@shadowmagic.org.uk
*/
#include "config.h"
#include <string.h>
#include "internals.h"
static const size_t SP_HEADER_LENGTH = 37;
libspectrum_error
libspectrum_sp_read( libspectrum_snap *snap, const libspectrum_byte *buffer,
size_t length )
{
libspectrum_error error;
libspectrum_word start, memory_length, flags;
libspectrum_byte *memory;
/* Length must be at least 48K of RAM plus the 'trailer' */
if( length < SP_HEADER_LENGTH ) {
libspectrum_print_error(
LIBSPECTRUM_ERROR_CORRUPT,
"libspectrum_sp_read: not enough bytes for .sp header"
);
return LIBSPECTRUM_ERROR_CORRUPT;
}
/* Check the signature */
if( buffer[0] != 'S' || buffer[1] != 'P' ) {
libspectrum_print_error(
LIBSPECTRUM_ERROR_SIGNATURE,
"libspectrum_sp_read: 'SP' signature not present"
);
return LIBSPECTRUM_ERROR_SIGNATURE;
}
buffer += 2;
memory_length = libspectrum_read_word( &buffer );
start = libspectrum_read_word( &buffer );
/* Check for overrun of 48K memory */
if( start + (libspectrum_dword)memory_length > 0x10000 ) {
libspectrum_print_error(
LIBSPECTRUM_ERROR_CORRUPT,
"libspectrum_sp_read: memory dump extends beyond 0xffff"
);
return LIBSPECTRUM_ERROR_CORRUPT;
}
if( start + memory_length < 0x8000 ) {
libspectrum_snap_set_machine( snap, LIBSPECTRUM_MACHINE_16 );
} else {
libspectrum_snap_set_machine( snap, LIBSPECTRUM_MACHINE_48 );
}
/* Note that `buffer' has been incremented by 6 above */
libspectrum_snap_set_bc ( snap, buffer[ 0] + buffer[ 1] * 0x100 );
libspectrum_snap_set_de ( snap, buffer[ 2] + buffer[ 3] * 0x100 );
libspectrum_snap_set_hl ( snap, buffer[ 4] + buffer[ 5] * 0x100 );
libspectrum_snap_set_f ( snap, buffer[ 6] );
libspectrum_snap_set_a ( snap, buffer[ 7] );
libspectrum_snap_set_ix ( snap, buffer[ 8] + buffer[ 9] * 0x100 );
libspectrum_snap_set_iy ( snap, buffer[10] + buffer[11] * 0x100 );
libspectrum_snap_set_bc_ ( snap, buffer[12] + buffer[13] * 0x100 );
libspectrum_snap_set_de_ ( snap, buffer[14] + buffer[15] * 0x100 );
libspectrum_snap_set_hl_ ( snap, buffer[16] + buffer[17] * 0x100 );
libspectrum_snap_set_f_ ( snap, buffer[18] );
libspectrum_snap_set_a_ ( snap, buffer[19] );
libspectrum_snap_set_r ( snap, buffer[20] );
libspectrum_snap_set_i ( snap, buffer[21] );
libspectrum_snap_set_sp ( snap, buffer[22] + buffer[23] * 0x100 );
libspectrum_snap_set_pc ( snap, buffer[24] + buffer[25] * 0x100 );
/* Bytes 32 and 33 not used */
libspectrum_snap_set_out_ula( snap, buffer[28] );
/* Byte 35 not used */
buffer += 30;
flags = libspectrum_read_word( &buffer );
libspectrum_snap_set_iff1 ( snap, flags & 0x01 );
libspectrum_snap_set_iff2 ( snap, ( flags & 0x04 ) >> 2 );
/* bit 3 1 | IM
--------+---
0 0 | 1
0 1 | 2
1 - | 0 */
libspectrum_snap_set_im( snap,
( flags & 0x08 ? 0 : ( flags & 0x02 ? 2 : 1 ) ) );
/* Get me 48K of zero-ed memory and then copy in the bits that were
represented in the snap */
memory = libspectrum_new0( libspectrum_byte, 0xc000 );
memcpy( &memory[ start ], buffer, memory_length );
error = libspectrum_split_to_48k_pages( snap, memory );
if( error ) { libspectrum_free( memory ); return error; }
libspectrum_free( memory );
return LIBSPECTRUM_ERROR_NONE;
}
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