This is an attempt to document the Berkeley changes to SPIMSAL as used
in the EECS Instructional environment. Please amend as necessary, and
whenever you make new changes.

Originally written 21 August 1999 by Brian Gaeke <brg@EECS.Berkeley.EDU>.

Last revised: $Date: 2001/06/04 23:43:47 $

* Bison will appear to successfully compile the SPIM parser.y, but the
  resulting parser will not work (loops infinitely at the end of each file.)
  You *must* use Berkeley or AT&T YACC to compile the SPIM parser.y, not Bison.

* Jeremy Lin <jjlin@cory.eecs.berkeley.edu> added "clear console" and
  "reload" options to xspim.

* Makefile changes to work on Solaris/SPARC.

* 'dumpnative' command dumps in the local byte order of the host you're on.
  'dump' dumps in big-endian (network) byte order. Both commands now take
  an optional argument, which is the filename to dump to if the default
  "spim.dump" is not desired.

* Phil Buonadonna's <philipb@cs.berkeley.edu> changes to make it compile
  under Cygwin b20 have been checked in.

* A couple of changes to spim.h in prototypes, to allow for compilation under
  Linux (it already compiles fine under Solaris/x86, and with some warnings
  under HP-UX.)

* Fixed a bug in the interface between spim and the flex scanner where if you
  tried to load a file (e.g., trap.handler) and then read from stdin it would
  use the wrong file descriptor and abort with "input in flex scanner failed".
  This involved adding some calls, as described in the flex man page, to
  destroy and re-create buffers when new filehandles are passed to
  scanner.l:initialize_scanner(). This was necessary to use flex 2.5.4
  to compile the scanner (the scanner we were using dated from 1990!)

* 'dump' command dumps text segment in network byte order to file 'spim.dump'
  in current working directory.

* Changes to Makefile/build process to look in /usr/sww for things and
  to put the trap handler under ~cs61c, and generally to help build under
  the Instructional environment(s).

* Changes to buttons.c to allow 'set value' to use chars as values, in xspim.
  Use 'a' (incl. single quotes) to set a register to 97, for example.

* inst.c includes assert.h, and next_text_pc is made global for use by 'dump'.

* In inst.c:print_inst(), the buffer size for printing instructions
  has been increased from 128 bytes to 3 Kbytes. This is a partial
  workaround for a very common spim core dump caused by a buffer overflow.

* In mem.h, the memory-mapped IO region has been moved from 0xbfff0000 to
  0xffff0000. (IO_BOT and IO_TOP functions changed.)

* In memio.c, the READY and INTER bits have been moved to the least-significant
  and second-to-least-significant bits, respectively; also the resetting of
  the status bits has been changed to only modify the appropriate bits, when
  necessary (instead of clearing the entire control register when some device
  becomes unready.) Also, the keyboards now do not become unready when written
  to.

* In memio.c, the BUF_ADDRs (memory-mapped data registers) for all
  memory-mapped I/O devices have been moved BEFORE the STAT_ADDRs
  (memory-mapped control registers), as opposed to their original
  configuration. The new mapping is:

  Keyboard 1 data register    0xffff0004
  Keyboard 1 control register 0xffff0000
  Display 1 data register     0xffff000c
  Display 1 control register  0xffff0008
  Keyboard 2 data register    0xffff0014
  Keyboard 2 control register 0xffff0010
  Display 2 data register     0xffff001c
  Display 2 control register  0xffff0018
  Clock control register      0xffff0020

* A futile attempt to update Tests/tt.memio.s was made.

* In parser.y, support for explicitly specifying the starting text and
  kernel-text segment starting addresses (.text ADDR and .ktext ADDR)
  has been added.

* In run.c, we look for "EXIT_SYSCALL" (10) instead of "EXIT_NOW_SYSCALL" (13)
  when processing the "done" macro.

$Id: CHANGES.UCB,v 1.9 2001/06/04 23:43:47 spim Exp $