add turbo pascal v3 patch app

Borland turbo pascal v3/patchtp3.cxx

@@ -0,0 +1,90 @@
+// Turbo Pascal v3.02a generates apps that try to determine the speed of the CPU at startup.
+// On emulators this can cause many instructions to be executed and throws off benchmark numbers.
+// This code replaces the call to do the speed check with NOP instructions.
+
+#include <stdio.h>
+#include <string.h>
+#include <process.h>
+#include <stdint.h>
+
+void usage()
+{
+    printf( "usage: p app.com\n" );
+    exit( 1 );
+} //usage
+
+long portable_filelen( FILE * fp )
+{
+    long current = ftell( fp );
+    fseek( fp, 0, SEEK_END );
+    long len = ftell( fp );
+    fseek( fp, current, SEEK_SET );
+    return len;
+} //portable_filelen
+
+int main( int argc, char * argv[] )
+{
+    if ( 2 != argc )
+        usage();
+
+    FILE * fp = fopen( argv[1], "r+b" );
+    if ( !fp )
+    {
+        printf( "can't open file %s\n", argv[1] );
+        usage();
+    }
+
+    long len = portable_filelen( fp );
+    if ( len < 0x8a9 )
+    {
+        printf( "file length: %ld\n", len );
+        printf( "file seems too small\n" );
+        exit( 1 );
+    }
+
+    char acBuf[ 32 ];
+    fseek( fp, 7, SEEK_SET );
+    fread( acBuf, 30, 1, fp );
+    acBuf[ 30 ] = 0;
+
+    if ( strcmp( acBuf, "Copyright (C) 1985 BORLAND Inc" ) )
+    {
+        printf( "file doesn't appear to be a Turbo Pascal v3.02a generated app\n" );
+        exit( 1 );
+    }
+
+    uint8_t abytes[ 3 ] = { 0 };
+    fseek( fp, 0x8a7, SEEK_SET );
+    fread( abytes, 3, 1, fp );
+
+    if ( 0x90 == abytes[ 0 ] && 0x90 == abytes[ 1 ] && 0x90 == abytes[ 2 ] )
+    {
+        printf( "file is apparently already patched\n" );
+        exit( 0 );
+    }
+
+    if ( 0xe8 != abytes[ 0 ] || 0xe8 != abytes[ 1 ] || 0xf7 != abytes[ 2 ] )
+    {
+        printf( "file doesn't have call 0f7e8h at offset 08a7h\n" );
+        printf( "values there: %02x, %02x, %02x\n", abytes[ 0 ], abytes[ 1 ], abytes[ 2 ] );
+        exit( 1 );
+    }
+
+    abytes[ 0 ] = 0x90;
+    abytes[ 1 ] = 0x90;
+    abytes[ 2 ] = 0x90;
+    fseek( fp, 0x8a7, SEEK_SET );
+    int result = fwrite( abytes, 3, 1, fp );
+    if ( 1 != result )
+    {
+        printf( "couldn't write the NOP instructions, error %d\n", errno );
+        exit( 1 );
+    }
+
+    fclose( fp );
+    printf( "file %s successfully patched to remove startup cpu timing code\n", argv[ 1 ] );
+
+    return 0;
+} //main
+
+