Tape endianness in Bob's simulator

Steven M. Schultz sms at moe.2bsd.com
Wed Dec 30 10:06:30 AEST 1998


Hi -

	In glancing thru Bob's simulator I spotted this:


* Endian independent binary I/O package

   For consistency, all binary data read and written by the simulator
   is stored in little endian data order.  That is, in a multi-byte
   data item, the bytes are written out right to left, low order byte
   to high order byte.  On a big endian host, data is read and written
   from high byte to low byte.  Consequently, data written on a little
   endian system must be byte reversed to be usable on a big endian
   system, and vice versa.


	Perhaps this sheds some light on why a Sparc can't read a pdp-11
	generated (via 'makesimtape') tape.

	I know I've read simulated tape files on an Intel system with no
	trouble - so it would appear that the endianness was correct.

	Good Luck Robin! ;)

	Steven

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