/* Fundamental definitions for XEmacs Lisp interpreter -- non-union objects. Copyright (C) 1985, 1986, 1987, 1992, 1993 Free Software Foundation, Inc. Copyright (C) 2001, 2002 Ben Wing. This file is part of XEmacs. XEmacs is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. XEmacs is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with XEmacs. If not, see . */ /* Synched up with: FSF 19.30. Split out from lisp.h. */ /* This file has diverged greatly from FSF Emacs. Syncing is no longer desirable or possible */ /* Format of a non-union-type Lisp Object 3 2 1 0 bit 10987654321098765432109876543210 -------------------------------- VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVTT Integers are treated specially, and look like this: 3 2 1 0 bit 10987654321098765432109876543210 -------------------------------- VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVT For integral Lisp types, i.e. integers and characters, the value bits are the Lisp object. Some people call such Lisp_Objects "immediate". The object is obtained by masking off the type bits. Bit 1 is used as a value bit by splitting the Lisp integer type into two subtypes, Lisp_Type_Fixnum_Even and Lisp_Type_Fixnum_Odd. By this trickery we get 31 bits for integers instead of 30. For non-integral types, the value bits of a Lisp_Object contain a pointer to a structure containing the object. The pointer is obtained by masking off the type and mark bits. All pointer-based types are coalesced under a single type called Lisp_Type_Record. The type bits for this type are required by the implementation to be 00, just like the least significant bits of word-aligned struct pointers on 32-bit hardware. This requires that all structs implementing Lisp_Objects have an alignment of at least 4 bytes. Because of this, Lisp_Object pointers don't have to be masked and are full-sized. There are no mark bits in the Lisp_Object itself (there used to be). Integers and characters don't need to be marked. All other types are lrecord-based, which means they get marked by setting the mark bit in the struct lrecord_header. Here is a brief description of the following macros: XTYPE The type bits of a Lisp_Object XPNTRVAL The value bits of a Lisp_Object storing a pointer XCHARVAL The value bits of a Lisp_Object storing a Ichar XREALFIXNUM The value bits of a Lisp_Object storing an integer, signed XUINT The value bits of a Lisp_Object storing an integer, unsigned FIXNUMP Non-zero if this Lisp_Object is an integer Qzero Lisp Integer 0 EQ Non-zero if two Lisp_Objects are identical, not merely equal. */ typedef EMACS_INT Lisp_Object; #define Lisp_Type_Fixnum_Bit (Lisp_Type_Fixnum_Even & Lisp_Type_Fixnum_Odd) #define VALMASK (((1UL << VALBITS) - 1UL) << GCTYPEBITS) #define XTYPE(x) ((enum Lisp_Type) (((EMACS_UINT)(x)) & ~VALMASK)) #define XPNTRVAL(x) (x) /* This depends on Lisp_Type_Record == 0 */ #define XCHARVAL(x) ((x) >> GCBITS) #define XREALFIXNUM(x) ((x) >> FIXNUM_GCBITS) #define XUINT(x) ((EMACS_UINT)(x) >> FIXNUM_GCBITS) #define wrap_pointer_1(ptr) ((Lisp_Object) (ptr)) DECLARE_INLINE_HEADER ( Lisp_Object make_fixnum_verify (EMACS_INT val) ) { Lisp_Object obj = (Lisp_Object) ((val << FIXNUM_GCBITS) | Lisp_Type_Fixnum_Bit); type_checking_assert (XREALFIXNUM (obj) == val); return obj; } #define make_fixnum(x) ((Lisp_Object) ((((EMACS_INT)(x)) << FIXNUM_GCBITS) | Lisp_Type_Fixnum_Bit)) #define make_char_1(x) ((Lisp_Object) ((((EMACS_UINT)(x)) << GCBITS) | Lisp_Type_Char)) #define FIXNUMP(x) ((EMACS_UINT)(x) & Lisp_Type_Fixnum_Bit) #define FIXNUM_PLUS(x,y) ((x)+(y)-Lisp_Type_Fixnum_Bit) #define FIXNUM_MINUS(x,y) ((x)-(y)+Lisp_Type_Fixnum_Bit) #define FIXNUM_PLUS1(x) FIXNUM_PLUS (x, make_fixnum (1)) #define FIXNUM_MINUS1(x) FIXNUM_MINUS (x, make_fixnum (1)) #define Qzero make_fixnum (0) #define Qnull_pointer ((Lisp_Object) 0) #define EQ(x,y) ((x) == (y)) /* WARNING!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! You can only GET_LISP_FROM_VOID something that had previously been STORE_LISP_IN_VOID'd. If you want to go the other way, use STORE_VOID_IN_LISP and GET_VOID_FROM_LISP, or use make_opaque_ptr(). */ /* Convert a Lisp object to a void * pointer, as when it needs to be passed to a toolkit callback function */ #define STORE_LISP_IN_VOID(larg) ((void *) (larg)) /* Convert a void * pointer back into a Lisp object, assuming that the pointer was generated by STORE_LISP_IN_VOID. */ #define GET_LISP_FROM_VOID(varg) ((Lisp_Object) (varg)) /* Convert a Lisp_Object into something that can't be used as an lvalue. Useful for type-checking. */ #define NON_LVALUE(larg) ((larg) + 0)