137 lines
3.2 KiB
C
137 lines
3.2 KiB
C
|
/*
|
||
|
|
* libtilemcore - Graphing calculator emulation library
|
||
|
|
*
|
||
|
|
* Copyright (C) 2009-2011 Benjamin Moody
|
||
|
|
*
|
||
|
|
* This library is free software; you can redistribute it and/or
|
||
|
|
* modify it under the terms of the GNU Lesser General Public License
|
||
|
|
* as published by the Free Software Foundation; either version 2.1 of
|
||
|
|
* the License, or (at your option) any later version.
|
||
|
|
*
|
||
|
|
* This library 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
|
||
|
|
* Lesser General Public License for more details.
|
||
|
|
*
|
||
|
|
* You should have received a copy of the GNU Lesser General Public
|
||
|
|
* License along with this library; if not, see
|
||
|
|
* <http://www.gnu.org/licenses/>.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifdef HAVE_CONFIG_H
|
||
|
|
# include <config.h>
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <string.h>
|
||
|
|
#include "tilem.h"
|
||
|
|
|
||
|
|
static int certificate_valid(byte* cert)
|
||
|
|
{
|
||
|
|
int i, n;
|
||
|
|
|
||
|
|
if (cert[0] != 0)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
i = 1;
|
||
|
|
|
||
|
|
/* check that the actual certificate area consists of valid
|
||
|
|
certificate fields */
|
||
|
|
while (cert[i] <= 0x0F) {
|
||
|
|
switch (cert[i + 1] & 0x0F) {
|
||
|
|
case 0x0D:
|
||
|
|
n = cert[i + 2] + 3;
|
||
|
|
break;
|
||
|
|
case 0x0E:
|
||
|
|
n = (cert[i + 2] << 8) + cert[i + 3] + 4;
|
||
|
|
break;
|
||
|
|
case 0x0F:
|
||
|
|
n = 6;
|
||
|
|
break;
|
||
|
|
default:
|
||
|
|
n = (cert[i + 1] & 0xf) + 2;
|
||
|
|
}
|
||
|
|
i += n;
|
||
|
|
if (i >= 0x2000)
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* check that the fields end with FF */
|
||
|
|
if (cert[i] != 0xFF)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
/* if there are fields present, assume the certificate is OK */
|
||
|
|
if (i > 1)
|
||
|
|
return 1;
|
||
|
|
|
||
|
|
/* no fields present -> this could be an incompletely-patched
|
||
|
|
certificate from an older version of TilEm; verify that the
|
||
|
|
next 4k bytes are truly empty */
|
||
|
|
while (i < 0x1000) {
|
||
|
|
if (cert[i] != 0xFF)
|
||
|
|
return 0;
|
||
|
|
i++;
|
||
|
|
}
|
||
|
|
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
void tilem_calc_fix_certificate(TilemCalc* calc, byte* cert,
|
||
|
|
int app_start, int app_end,
|
||
|
|
unsigned exptab_offset)
|
||
|
|
{
|
||
|
|
int i, base, max_apps, page;
|
||
|
|
unsigned insttab_offset = 0x1fe0;
|
||
|
|
|
||
|
|
/* If the ROM was dumped from an unpatched OS, the certificate
|
||
|
|
needs to be patched for some calculator functions to
|
||
|
|
work. */
|
||
|
|
|
||
|
|
/* First, check if the certificate is already valid */
|
||
|
|
|
||
|
|
if (cert[0x2000] == 0)
|
||
|
|
base = 0x2000;
|
||
|
|
else
|
||
|
|
base = 0;
|
||
|
|
|
||
|
|
if (certificate_valid(cert + base)) {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
tilem_message(calc, "Repairing certificate area...");
|
||
|
|
|
||
|
|
memset(cert, 0xff, 16384);
|
||
|
|
|
||
|
|
cert[0] = 0;
|
||
|
|
|
||
|
|
cert[insttab_offset] = 0xfe;
|
||
|
|
|
||
|
|
if (app_start < app_end)
|
||
|
|
max_apps = app_end - app_start + 1;
|
||
|
|
else
|
||
|
|
max_apps = app_start - app_end + 1;
|
||
|
|
|
||
|
|
for (i = 0; i < max_apps; i++) {
|
||
|
|
if (app_start < app_end)
|
||
|
|
page = app_start + i;
|
||
|
|
else
|
||
|
|
page = app_start - i;
|
||
|
|
|
||
|
|
/* Clear installed bit / set expiration count for
|
||
|
|
existing apps. (If this incorrectly detects pages
|
||
|
|
that aren't really apps, don't worry about it;
|
||
|
|
better to err on the side of caution.) */
|
||
|
|
if (calc->mem[page << 14] != 0x80
|
||
|
|
|| calc->mem[(page << 14) + 1] != 0x0f)
|
||
|
|
continue;
|
||
|
|
|
||
|
|
tilem_message(calc, "Found application at page %02x (index %d)",
|
||
|
|
page, i);
|
||
|
|
|
||
|
|
cert[insttab_offset + ((i + 1) / 8)] &= ~(1 << ((i + 1) % 8));
|
||
|
|
|
||
|
|
cert[exptab_offset + 2 * i] = 0x80;
|
||
|
|
cert[exptab_offset + 2 * i + 1] = 0x00;
|
||
|
|
}
|
||
|
|
}
|