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#include <stdio.h>
#include <stdlib.h>
/*
A part of Fopen/Fcreate routine... (adding #100 to the file handle for in mem data)
L2334:
move.l a5,4(a4) ; 294D0004
clr.l (a4) ; 4294
addq #1,10(a5) ; 526D000A
moveq #100,d0 ; 7064
add d4,d0 ; D044
L2348:
addq #6,a7 ; 5C4F
movem.l (a7)+,d3-d4/a3-a5 ; 4CDF3818
rts ; 4E75
*/
unsigned char moveq100[] = {
0x29, 0x4d, 0x00, 0x04,
0x42, 0x94,
0x52, 0x6d, 0x00, 0x0a,
0x70, 0x64,
0xd0, 0x44,
0x5c, 0x4f,
0x4c, 0xdf, 0x38, 0x18,
0x4e, 0x75,
};
/*
A parts of Fread/Fdatime/Fseek/Fclose routines... (fh #100..#140)
L2356:
movem.l d3-d4/a2-a4,-(a7) ; 48E71838
move d0,d3 ; 3600
movea.l a0,a2 ; 2448
move.l d1,d4 ; 2801
cmp #100,d0 ; B07C0064
blt.s L2378 ; 6D06
cmp #140,d0 ; B07C008C
blt.s L2392 ; 6D0E
L2378:
move.l d4,d1 ; 2204
movea.l a2,a0 ; 204A
move d3,d0 ; 3003
jsr L173498 ; 4EB90002A5BA
bra.s L2456 ; 6040
L2392:
sub #100,d3 ; 967C0064
move d3,d0 ; 3003
lsl #3,d0 ; E748
lea U223702,a3 ; 47F9000369D6
adda d0,a3 ; D6C0
*/
unsigned char cmp100140[] = {
0xb0, 0x7c, 0x00, 0x64,
0x6d, 0x06,
0xb0, 0x7c, 0x00, 0x8c,
};
unsigned char sub100d3[] = {
0x96, 0x7c, 0x00, 0x64,
0x30, 0x03,
};
FILE *fh;
unsigned char patchBuffer[2];
int getByte( unsigned char *buff ) {
return fread( (void*)buff, 1, 1, fh ) == -1 ? -1 : 1;
}
int findPart( unsigned char *buffer, size_t len )
{
unsigned char charBuffer[2];
int idx = 0;
int total = 0;
while ( getByte( charBuffer ) > 0 ) {
if ( idx >= len )
return 1;
if ( *charBuffer != buffer[idx] )
idx = 0;
else
idx++;
if ( total++ > 2000 )
return 0;
}
return 0;
}
int main() {
char *result = NULL;
fh = fopen ("PC.PRG", "rb+");
if ( !fh ) {
result = "PC.PRG not found in current directory";
goto finalize;
}
if ( fseek( fh, 2000, SEEK_SET ) < 0 ) {
result = "PC.PRG cannot seek to 2000 (too short file?)";
goto finalize;
}
if ( ! findPart( moveq100, sizeof( moveq100 ) / sizeof( *moveq100 ) ) ) {
result = "findPart(moveq100) failed";
goto finalize;
}
*patchBuffer = 200;
fseek( fh, -12, SEEK_CUR );
fwrite( patchBuffer, 1, 1, fh );
while ( 1 ) {
if ( ! findPart( cmp100140, sizeof( cmp100140 ) / sizeof( *cmp100140 ) ) ) {
result = "findPart(cmp100140) failed";
break;
}
*patchBuffer = 200;
fseek( fh, -8, SEEK_CUR );
fwrite( patchBuffer, 1, 1, fh );
*patchBuffer = 240;
fseek( fh, 5, SEEK_CUR );
fwrite( patchBuffer, 1, 1, fh );
if ( ! findPart( sub100d3, sizeof( sub100d3 ) / sizeof( *sub100d3 ) ) ) {
result = "findPart(sub100d3) failed";
break;
}
*patchBuffer = 200;
fseek( fh, -4, SEEK_CUR );
fwrite( patchBuffer, 1, 1, fh );
}
finalize:
fclose( fh );
if ( result == NULL ) {
printf( "PureC was patched successfully.\n" );
} else {
printf( "Error patching PureC: %s\n", result );
}
puts("Press [Return] to quit.");
getchar();
return 0;
}
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