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128 lines
4.2 KiB
C
128 lines
4.2 KiB
C
/* sp.c: Routines for handling .sp snapshots
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Copyright (c) 1998,2003 Philip Kendall
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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Author contact information:
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E-mail: philip-fuse@shadowmagic.org.uk
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*/
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#include "config.h"
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#include <string.h>
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#include "internals.h"
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static const size_t SP_HEADER_LENGTH = 37;
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libspectrum_error
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libspectrum_sp_read( libspectrum_snap *snap, const libspectrum_byte *buffer,
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size_t length )
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{
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libspectrum_error error;
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libspectrum_word start, memory_length, flags;
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libspectrum_byte *memory;
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/* Length must be at least 48K of RAM plus the 'trailer' */
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if( length < SP_HEADER_LENGTH ) {
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libspectrum_print_error(
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LIBSPECTRUM_ERROR_CORRUPT,
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"libspectrum_sp_read: not enough bytes for .sp header"
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);
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return LIBSPECTRUM_ERROR_CORRUPT;
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}
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/* Check the signature */
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if( buffer[0] != 'S' || buffer[1] != 'P' ) {
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libspectrum_print_error(
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LIBSPECTRUM_ERROR_SIGNATURE,
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"libspectrum_sp_read: 'SP' signature not present"
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);
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return LIBSPECTRUM_ERROR_SIGNATURE;
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}
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buffer += 2;
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memory_length = libspectrum_read_word( &buffer );
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start = libspectrum_read_word( &buffer );
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/* Check for overrun of 48K memory */
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if( start + (libspectrum_dword)memory_length > 0x10000 ) {
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libspectrum_print_error(
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LIBSPECTRUM_ERROR_CORRUPT,
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"libspectrum_sp_read: memory dump extends beyond 0xffff"
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);
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return LIBSPECTRUM_ERROR_CORRUPT;
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}
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if( start + memory_length < 0x8000 ) {
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libspectrum_snap_set_machine( snap, LIBSPECTRUM_MACHINE_16 );
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} else {
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libspectrum_snap_set_machine( snap, LIBSPECTRUM_MACHINE_48 );
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}
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/* Note that `buffer' has been incremented by 6 above */
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libspectrum_snap_set_bc ( snap, buffer[ 0] + buffer[ 1] * 0x100 );
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libspectrum_snap_set_de ( snap, buffer[ 2] + buffer[ 3] * 0x100 );
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libspectrum_snap_set_hl ( snap, buffer[ 4] + buffer[ 5] * 0x100 );
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libspectrum_snap_set_f ( snap, buffer[ 6] );
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libspectrum_snap_set_a ( snap, buffer[ 7] );
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libspectrum_snap_set_ix ( snap, buffer[ 8] + buffer[ 9] * 0x100 );
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libspectrum_snap_set_iy ( snap, buffer[10] + buffer[11] * 0x100 );
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libspectrum_snap_set_bc_ ( snap, buffer[12] + buffer[13] * 0x100 );
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libspectrum_snap_set_de_ ( snap, buffer[14] + buffer[15] * 0x100 );
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libspectrum_snap_set_hl_ ( snap, buffer[16] + buffer[17] * 0x100 );
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libspectrum_snap_set_f_ ( snap, buffer[18] );
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libspectrum_snap_set_a_ ( snap, buffer[19] );
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libspectrum_snap_set_r ( snap, buffer[20] );
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libspectrum_snap_set_i ( snap, buffer[21] );
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libspectrum_snap_set_sp ( snap, buffer[22] + buffer[23] * 0x100 );
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libspectrum_snap_set_pc ( snap, buffer[24] + buffer[25] * 0x100 );
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/* Bytes 32 and 33 not used */
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libspectrum_snap_set_out_ula( snap, buffer[28] );
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/* Byte 35 not used */
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buffer += 30;
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flags = libspectrum_read_word( &buffer );
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libspectrum_snap_set_iff1 ( snap, flags & 0x01 );
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libspectrum_snap_set_iff2 ( snap, ( flags & 0x04 ) >> 2 );
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/* bit 3 1 | IM
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--------+---
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0 0 | 1
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0 1 | 2
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1 - | 0 */
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libspectrum_snap_set_im( snap,
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( flags & 0x08 ? 0 : ( flags & 0x02 ? 2 : 1 ) ) );
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/* Get me 48K of zero-ed memory and then copy in the bits that were
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represented in the snap */
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memory = libspectrum_new0( libspectrum_byte, 0xc000 );
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memcpy( &memory[ start ], buffer, memory_length );
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error = libspectrum_split_to_48k_pages( snap, memory );
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if( error ) { libspectrum_free( memory ); return error; }
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libspectrum_free( memory );
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return LIBSPECTRUM_ERROR_NONE;
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}
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