/*
** 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: bytecode.h,v 1.12 1997/07/27 14:59:19 fjh Exp $
*/

/*
** This file defines the bytecode format.
** The definitions here must match those in compiler/bytecode.m.
*/

#ifndef MB_BYTECODE_H
#define	MB_BYTECODE_H

#include	"conf.h"
#include	"mercury_types.h"
#include	"mercury_float.h"
#include	"gc.h"

/*
 * XXX: We should make bytecode portable from platform to platform.
 *
 * We require the following:
 *	sizeof(MB_Byte) = 1
 *	sizeof(MB_Short16) = 2 (2's complement)
 *	sizeof(MB_Integer64) = 8 (2's complement)
 *	sizeof(Float64) = 8 (IEEE)	// We don't really need float.
 * Each of the above is big-endian in the bytecode file.
 * That is, we read the byte at the big end first.
 *
 * We should have platform-dependent #defines to ensure that each of
 * these types has identical size on all platforms.
 */

typedef unsigned char
	MB_Byte;

typedef short
	MB_Short;

typedef char*
	MB_CString;

typedef struct MB_Tag_struct {
	MB_Byte	id;
	union {
		MB_Byte	primary;
		struct {
			MB_Byte	primary;
			Word	secondary; 
		} pair;
		MB_Byte	enum_tag;
	} opt;
} MB_Tag;


/* 
 *	Possible values for Tag.id ...
 */
#define	MB_TAG_SIMPLE			0
#define	MB_TAG_COMPLICATED		1
#define	MB_TAG_COMPLICATED_CONSTANT	2
#define	MB_TAG_ENUM			3
#define	MB_TAG_NONE			4


typedef MB_Byte
	MB_Determinism;
/*
 *	Possible values for Determinism ...
 */
#define	MB_DET_DET			0
#define	MB_DET_SEMIDET			1
#define	MB_DET_MULTIDET			2
#define	MB_DET_NONDET			3
#define	MB_DET_CC_MULTIDET		4
#define	MB_DET_CC_NONDET		5
#define	MB_DET_ERRONEOUS		6
#define	MB_DET_FAILURE			7

typedef struct MB_Op_arg_struct {
	MB_Byte	id;
	union {
		MB_Short	var;
		Integer 	int_const;
		Float		float_const;
	} opt;
} MB_Op_arg;

/*
 *	Possible values for Op_arg.id
 */
#define	MB_ARG_VAR			0
#define	MB_ARG_INT_CONST		1
#define	MB_ARG_FLOAT_CONST		2


typedef MB_Byte
	MB_Direction;

typedef struct MB_Var_dir_struct {
	MB_Short	var;
	MB_Direction	dir;
} MB_Var_dir;

/*
 *	Possible values for Direction ...
 */
#define	MB_DIR_TO_ARG		0
#define	MB_DIR_TO_VAR		1
#define	MB_DIR_TO_NONE		2


typedef struct MB_Cons_id_struct {
	MB_Byte	id;
	union {
		struct {
			MB_CString	module_id;
			MB_CString	string;
			MB_Short	arity;
			MB_Tag		tag;
		} cons;
		Integer		int_const;	
		MB_CString	string_const;
		Float		float_const;
		struct {
			MB_CString	module_id;
			MB_CString	pred_id;
			MB_Short	arity;
			MB_Byte		proc_id;
		} pred_const;
		struct {
			MB_CString	module_id;
			MB_CString	pred_id;
			MB_Short	arity;
			MB_Byte		proc_id;
		} code_addr_const;
		struct {
			MB_CString	module_id;
			MB_CString	type_name;
			MB_Byte		type_arity;
		} base_type_info_const;
		struct {
			MB_Byte		ch;
		} char_const;
	} opt;
} MB_Cons_id;

/*
 *	Possible values for Cons_id.id ...
 */
#define	MB_CONSID_CONS			0
#define	MB_CONSID_INT_CONST		1
#define	MB_CONSID_STRING_CONST		2
#define	MB_CONSID_FLOAT_CONST		3
#define	MB_CONSID_PRED_CONST		4
#define	MB_CONSID_CODE_ADDR_CONST	5
#define	MB_CONSID_BASE_TYPE_INFO_CONST	6
#define	MB_CONSID_CHAR_CONST		7


typedef struct MB_Bytecode_struct {
	MB_Byte	id;	/* Which bytecode instruction. e.g. BC_fail */
	union {
		struct {
			MB_CString	pred_name;	/* XXX: malloc */
			MB_Short	proc_count;
		} enter_pred;

		/* endof_pred */

		struct {
			MB_Byte		proc_id;
			MB_Determinism	det;
			MB_Short	label_count;
			MB_Short	temp_count;
			MB_Short	list_length;
			MB_CString	*var_info_list; /* XXX: malloc */
		} enter_proc;

		struct {
			MB_Short	label;
		} label;

		struct {
			MB_Short	end_label;
		} enter_disjunction;

		/* endof_disjunction */

		struct {
			MB_Short	next_label;
		} enter_disjunct;

		struct {
			MB_Short	label; /* XXX: what's label for? */
		} endof_disjunct;

		struct {
			MB_Short	var;
			MB_Short	end_label;
		} enter_switch;
			
		/* endof_switch */

		struct {
			MB_Cons_id	cons_id;
			MB_Short	next_label;
		} enter_switch_arm;

		struct {
			MB_Short	label;	/* XXX: what's this label for? */
		} endof_switch_arm;

		struct {
			MB_Short	else_label;
			MB_Short	end_label;
			MB_Short	frame_ptr_tmp;
		} enter_if;

		struct {
			MB_Short	frame_ptr_tmp;
		} enter_then;
		
		struct {
			MB_Short	follow_label;
		} endof_then;	/* XXX: should rename to enter_else */

		/* endof_if */
	
		struct {
			MB_Short	end_label;
		} enter_negation;

		/* endof_negation */

		struct {
			MB_Short	temp;	
		} enter_commit;

		struct {
			MB_Short	temp;	
		} endof_commit;

		struct {
			MB_Short	to_var;
			MB_Short	from_var;
		} assign;

		struct {
			MB_Short	var1;
			MB_Short	var2;
		} test;

		struct {
			MB_Short	to_var;
			MB_Cons_id	consid;
			MB_Short	list_length;
			MB_Short	*var_list;	/* XXX: malloc */
		} construct;

		struct {
			MB_Short	from_var;
			MB_Cons_id	consid;
			MB_Short	list_length;
			MB_Short	*var_list;	/* XXX: malloc */
		} deconstruct;

		struct {
			MB_Short	to_var;
			MB_Cons_id	consid;
			MB_Short	list_length;
			MB_Var_dir	*var_dir_list;/* XXX: malloc */	
		} complex_construct;

		struct {
			MB_Short	from_var;
			MB_Cons_id	consid;
			MB_Short	list_length;
			MB_Var_dir	*var_dir_list;/* XXX: malloc */
		} complex_deconstruct;

		struct {
			MB_Byte		to_reg;
			MB_Short	from_var;
		} place_arg;

		struct {
			MB_Byte		from_reg;
			MB_Short	to_var;
		} pickup_arg;
			
		struct {
			MB_CString	module_id;	/* XXX: malloc */
			MB_CString	pred_id;	/* XXX: malloc */
			MB_Short	arity;
			MB_Byte		proc_id;
		} call;

		struct  {
			MB_Short	pred_var;
			MB_Short	in_var_count;
			MB_Short	out_var_count;
			MB_Determinism	det;
		} higher_order_call;

		struct {
			MB_Byte		binop;
			MB_Op_arg	arg1;
			MB_Op_arg	arg2;
			MB_Short	to_var;
		} builtin_binop;

		struct {
			MB_Byte		unop;
			MB_Op_arg	arg;
			MB_Short	to_var;
		} builtin_unop;

		struct {
			MB_Byte		binop;
			MB_Op_arg	arg1;
			MB_Op_arg	arg2;
		} builtin_bintest;	

		struct {
			MB_Byte		unop;
			MB_Op_arg	arg;
		} builtin_untest;	

		/* semidet_succeed */

		/* semidet_success_check */

		/* fail */

		struct {
			/* XXX: is this int or short?? */
			MB_Short	line_number;
		} context;

		/* not_supported */

	} opt;
} MB_Bytecode;

/*
 *	Possible values for Bytecode.id ...
 *
 *	We use #defines rather than an enumeration here since
 *	C enumeration constant must be of type int whereas we
 *	want byte (unsigned char).   XXX the preceding comment is
 *	a bogus explanation, because the constants are #defines
 *	for integerliterals, which are of type int anyway.
 */
#define	MB_BC_enter_pred		0
#define	MB_BC_endof_pred		1
#define	MB_BC_enter_proc		2
#define	MB_BC_endof_proc		3
#define	MB_BC_label			4
#define MB_BC_enter_disjunction		5
#define	MB_BC_endof_disjunction		6
#define	MB_BC_enter_disjunct		7
#define	MB_BC_endof_disjunct		8
#define	MB_BC_enter_switch		9
#define	MB_BC_endof_switch		10
#define	MB_BC_enter_switch_arm		11
#define	MB_BC_endof_switch_arm		12
#define	MB_BC_enter_if			13
#define	MB_BC_enter_then		14
/* XXX: enter_else would be a better name than endof_then */
#define	MB_BC_endof_then		15
#define	MB_BC_endof_if			16
#define	MB_BC_enter_negation		17
#define	MB_BC_endof_negation		18
#define	MB_BC_enter_commit		19
#define	MB_BC_endof_commit		20
#define	MB_BC_assign			21
#define	MB_BC_test			22
#define	MB_BC_construct			23
#define	MB_BC_deconstruct		24
#define	MB_BC_complex_construct		25
#define	MB_BC_complex_deconstruct	26
#define	MB_BC_place_arg			27
#define	MB_BC_pickup_arg		28
#define	MB_BC_call			29
#define	MB_BC_higher_order_call		30
#define	MB_BC_builtin_binop		31
#define	MB_BC_builtin_unop		32
#define	MB_BC_builtin_bintest		33
#define	MB_BC_builtin_untest		34
#define	MB_BC_semidet_succeed		35
#define	MB_BC_semidet_success_check	36
#define	MB_BC_fail			37
#define	MB_BC_context			38
#define	MB_BC_not_supported		39
#define	MB_BC_noop			255

/*
 *	Read the next bytecode from the stream fp.
 *	If no bytecode can be read, return FALSE.
 *	Otherwise, return TRUE.
 */
MB_Bool
MB_read_bytecode(FILE *fp, MB_Bytecode *bc_p);

/*
 *	Read the bytecode version number from the stream fp.
 *	If the version number cannot be read, return FALSE.
 *	Otherwise, return TRUE.
 */
MB_Bool
MB_read_bytecode_version_number(FILE *fp, MB_Short *version_number_p);

#endif	/* MB_BYTECODE_H */