The beginnings of the new bytecode interpreter.

Estimated hours taken: 40

 The beginnings of the new bytecode interpreter. Probably
 just over half the code is the same or a
 superficially modified revision of the old one.

bytecode/mb_bytecode.c
bytecode/mb_bytecode.h
	Almost identical. Only real change is made MB_read_cstring not use
	any static variables

bytecode/mb_disasm.c
bytecode/mb_disasm.h
	Again, code very similar. Changed all the functions to write to a
	buffer instead of a file and to allow for bytecode indenting. Output
	format string for some instructions changed (hopefully more menaingful
	than just a dump of numbers)

bytecode/mb_machine.c
bytecode/mb_machine.h
	(completely different from old machine.c)
	The actual part that contains an abstract machine.
	 The rest is really just support code.
	 The instruction_table array is how instructions are dispatched. Look
	 at instr_xxxx for the actual interpreter code. Not all instructions
	 are implemented. MB_step and MB_run execute the actual
	  interpreting code

bytecode/mb_machine_show.h
bytecode/mb_machine_show.c
	  displays output showing the state of the machine


bytecode/mb_mem.c
bytecode/mb_mem.h
	  Identical to old mem apart from file name changes

bytecode/mb_util.c
bytecode/mb_util.h
	  took out strdup (not needed) and changed some comments

bytecode/mb_stack.c
bytecode/mb_stack.h
	  word based stack that will reallocate itself if it needs to


bytecode/mbi.c
	  front end for bytecode interpreter

bytecode/mdis.c
	  disassembles a file and dumps it to the screen

bytecode/mb_stack.h

@@ -0,0 +1,56 @@
+
+/*
+** Copyright (C) 1997 The University of Melbourne.
+** This file may only be copied under the terms of the GNU Library General
+** Public License - see the file COPYING.LIB in the Mercury distribution.
+**
+** $Id: mb_stack.h,v 1.1 2001-01-24 07:42:28 lpcam Exp $
+**
+** High-water marked stack of 'MB_Word's
+**
+*/
+
+
+#ifndef MB_STACK_H
+#define	MB_STACK_H
+
+#include "mb_bytecode.h"
+
+typedef struct {
+	MB_Word*data;
+	MB_Word	sp;
+	MB_Word max_size;
+} MB_Stack;
+
+/* allocates space for a new stack */
+MB_Stack	MB_stack_new(MB_Word init_size);
+/* get number of words already pushed on stack */
+MB_Word		MB_stack_size(MB_Stack* s);
+/* pushes a value onto the stack */
+void		MB_stack_push(MB_Stack* s, MB_Word x);
+/* removes a value off the stack */
+MB_Word		MB_stack_pop(MB_Stack* s);
+/* allocates space for multiple places on the stack */
+/* return value is index of lowest word */
+MB_Word		MB_stack_alloc(MB_Stack* s, MB_Word num_words);
+/* remove multiple items off the stack */
+void		MB_stack_free(MB_Stack* s, MB_Word num_words);
+/* peek at an item at a given stack index*/
+MB_Word		MB_stack_peek(MB_Stack* s, MB_Word idx);
+/* peek at an item index items away from the top of the stack */
+MB_Word		MB_stack_peek_rel(MB_Stack* s, MB_Word idx);
+/* get the address for the item at index
+** Note: if you add or remove items, this value could change */
+MB_Word*	MB_stack_peek_p(MB_Stack* s, MB_Word idx);
+/* get the address for the item at index relative to the top of the stack */
+MB_Word*	MB_stack_peek_rel_p(MB_Stack* s, MB_Word idx);
+/* Set the value of an item on the stack */
+void		MB_stack_poke(MB_Stack* s, MB_Word idx, MB_Word x);
+/* Set the value of an item on the stack, idx items from the top */
+void		MB_stack_poke_rel(MB_Stack* s, MB_Word rel_idx, MB_Word value);
+/* deallocate space for the stack */
+void		MB_stack_delete(MB_Stack* s);
+
+#endif	/* MB_STACK_H */
+
+