1
/* biossums.c --- written by Eike W. for the Bochs BIOS */
2
/* adapted for the LGPL'd VGABIOS by vruppert */
4
/* This library is free software; you can redistribute it and/or
5
* modify it under the terms of the GNU Lesser General Public
6
* License as published by the Free Software Foundation; either
7
* version 2 of the License, or (at your option) any later version.
9
* This library is distributed in the hope that it will be useful,
10
* but WITHOUT ANY WARRANTY; without even the implied warranty of
11
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12
* Lesser General Public License for more details.
14
* You should have received a copy of the GNU Lesser General Public
15
* License along with this library; if not, write to the Free Software
16
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22
typedef unsigned char byte;
24
void check( int value, char* message );
26
#define MAX_BIOS_DATA 0x10000
28
long chksum_bios_get_offset( byte* data, long offset );
29
byte chksum_bios_calc_value( byte* data, long offset );
30
byte chksum_bios_get_value( byte* data, long offset );
31
void chksum_bios_set_value( byte* data, long offset, byte value );
34
#define PMID_CHKSUM 19
36
long chksum_pmid_get_offset( byte* data, long offset );
37
byte chksum_pmid_calc_value( byte* data, long offset );
38
byte chksum_pmid_get_value( byte* data, long offset );
39
void chksum_pmid_set_value( byte* data, long offset, byte value );
43
long chksum_pcir_get_offset( byte* data, long offset );
46
byte bios_data[MAX_BIOS_DATA];
50
int main(int argc, char* argv[])
53
long offset, tmp_offset, pcir_offset;
54
byte bios_len_byte, cur_val = 0, new_val = 0;
58
printf( "Error. Need a file-name as an argument.\n" );
62
if ((stream = fopen(argv[1], "rb")) == NULL) {
63
printf("Error opening %s for reading.\n", argv[1]);
66
memset(bios_data, 0, MAX_BIOS_DATA);
67
bios_len = fread(bios_data, 1, MAX_BIOS_DATA, stream);
68
if (bios_len > MAX_BIOS_DATA) {
69
printf("Error reading max. 65536 Bytes from %s.\n", argv[1]);
75
if (bios_len < 0x8000) {
78
} else if ((bios_len & 0x1FF) != 0) {
79
bios_len = (bios_len + 0x200) & ~0x1FF;
82
bios_len_byte = (byte)(bios_len / 512);
83
if (bios_len_byte != bios_data[2]) {
87
bios_data[2] = (byte)(bios_len / 512);
93
while( (tmp_offset = chksum_pmid_get_offset( bios_data, offset )) != -1L ) {
95
cur_val = chksum_pmid_get_value( bios_data, offset );
96
new_val = chksum_pmid_calc_value( bios_data, offset );
97
printf( "\nPMID entry at: 0x%4lX\n", offset );
98
printf( "Current checksum: 0x%02X\n", cur_val );
99
printf( "Calculated checksum: 0x%02X ", new_val );
102
if ((hits == 1) && (cur_val != new_val)) {
103
printf("Setting checksum.");
104
chksum_pmid_set_value( bios_data, offset, new_val );
112
printf( "Multiple PMID entries! No checksum set." );
119
pcir_offset = chksum_pcir_get_offset( bios_data, offset );
120
if (pcir_offset != -1L) {
121
if (bios_data[pcir_offset + 16] != bios_data[2]) {
122
bios_data[pcir_offset + 16] = bios_data[2];
126
bios_data[pcir_offset + 16]++;
134
offset = chksum_bios_get_offset(bios_data, offset);
135
cur_val = chksum_bios_get_value(bios_data, offset);
136
new_val = chksum_bios_calc_value(bios_data, offset);
137
if ((cur_val != new_val) && (modified == 0)) {
140
if (pcir_offset != -1L) {
141
bios_data[pcir_offset + 16]++;
145
printf("\nBios checksum at: 0x%4lX\n", offset);
146
printf("Current checksum: 0x%02X\n", cur_val);
147
printf("Calculated checksum: 0x%02X ", new_val);
148
if (cur_val != new_val) {
149
printf("Setting checksum.");
150
chksum_bios_set_value(bios_data, offset, new_val);
156
} while (cur_val != new_val);
159
if ((stream = fopen( argv[1], "wb")) == NULL) {
160
printf("Error opening %s for writing.\n", argv[1]);
163
if (fwrite(bios_data, 1, bios_len, stream) < bios_len) {
164
printf("Error writing %d KBytes to %s.\n", bios_len / 1024, argv[1]);
171
return (EXIT_SUCCESS);
175
void check( int okay, char* message ) {
178
printf( "\n\nError. %s.\n", message );
179
exit( EXIT_FAILURE );
184
long chksum_bios_get_offset( byte* data, long offset ) {
186
return (bios_len - 1);
190
byte chksum_bios_calc_value( byte* data, long offset ) {
196
for( i = 0; i < offset; i++ ) {
197
sum = sum + *( data + i );
199
sum = -sum; /* iso ensures -s + s == 0 on unsigned types */
204
byte chksum_bios_get_value( byte* data, long offset ) {
206
return( *( data + offset ) );
210
void chksum_bios_set_value( byte* data, long offset, byte value ) {
212
*( data + offset ) = value;
216
byte chksum_pmid_calc_value( byte* data, long offset ) {
223
check((offset + len) <= (bios_len - 1), "PMID entry length out of bounds" );
225
for( i = 0; i < len; i++ ) {
226
if( i != PMID_CHKSUM ) {
227
sum = sum + *( data + offset + i );
235
long chksum_pmid_get_offset( byte* data, long offset ) {
239
while ((offset + PMID_LEN) < (bios_len - 1)) {
241
if( *( data + offset + 0 ) == 'P' && \
242
*( data + offset + 1 ) == 'M' && \
243
*( data + offset + 2 ) == 'I' && \
244
*( data + offset + 3 ) == 'D' ) {
253
byte chksum_pmid_get_value( byte* data, long offset ) {
255
check((offset + PMID_CHKSUM) <= (bios_len - 1), "PMID checksum out of bounds" );
256
return( *( data + offset + PMID_CHKSUM ) );
260
void chksum_pmid_set_value( byte* data, long offset, byte value ) {
262
check((offset + PMID_CHKSUM) <= (bios_len - 1), "PMID checksum out of bounds" );
263
*( data + offset + PMID_CHKSUM ) = value;
267
long chksum_pcir_get_offset( byte* data, long offset ) {
271
while ((offset + PCIR_LEN) < (bios_len - 1)) {
273
if( *( data + offset + 0 ) == 'P' && \
274
*( data + offset + 1 ) == 'C' && \
275
*( data + offset + 2 ) == 'I' && \
276
*( data + offset + 3 ) == 'R' ) {