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comparison src/lisp-disunion.h @ 398:74fd4e045ea6 r21-2-29

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Import from CVS: tag r21-2-29
author cvs
date Mon, 13 Aug 2007 11:13:30 +0200
parents 8626e4521993
children 697ef44129c6
comparison
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397:f4aeb21a5bad 398:74fd4e045ea6
23 longer desirable or possible */ 23 longer desirable or possible */
24 24
25 /* 25 /*
26 Format of a non-union-type Lisp Object 26 Format of a non-union-type Lisp Object
27 27
28 For the USE_MINIMAL_TAGBITS implementation:
29
30 3 2 1 0 28 3 2 1 0
31 bit 10987654321098765432109876543210 29 bit 10987654321098765432109876543210
32 -------------------------------- 30 --------------------------------
33 VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVTT 31 VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVTT
34 32
37 3 2 1 0 35 3 2 1 0
38 bit 10987654321098765432109876543210 36 bit 10987654321098765432109876543210
39 -------------------------------- 37 --------------------------------
40 VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVT 38 VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVT
41 39
42 For the non-USE_MINIMAL_TAGBITS implementation:
43
44 3 2 1 0
45 bit 10987654321098765432109876543210
46 --------------------------------
47 TTTMVVVVVVVVVVVVVVVVVVVVVVVVVVVV
48
49 V = value bits
50 T = type bits
51 M = mark bits
52
53 For integral Lisp types, i.e. integers and characters, the value 40 For integral Lisp types, i.e. integers and characters, the value
54 bits are the Lisp object. 41 bits are the Lisp object.
55 42
56 The object is obtained by masking off the type and mark 43 The object is obtained by masking off the type and mark bits.
57 bits. In the USE_MINIMAL_TAGBITS implementation, bit 1 is 44 Bit 1 is used as a value bit by splitting the Lisp integer type
58 used as a value bit by splitting the Lisp integer type into 45 into two subtypes, Lisp_Type_Int_Even and Lisp_Type_Int_Odd. By
59 two subtypes, Lisp_Type_Int_Even and Lisp_Type_Int_Odd. By
60 this trickery we get 31 bits for integers instead of 30. 46 this trickery we get 31 bits for integers instead of 30.
61
62 In the non-USE_MINIMAL_TAGBITS world, Lisp integers are 28 bits,
63 or more properly (BITS_PER_EMACS_INT - GCTYPEBITS - 1) bits.
64 47
65 For non-integral types, the value bits of a Lisp_Object contain 48 For non-integral types, the value bits of a Lisp_Object contain
66 a pointer to a structure containing the object. The pointer is 49 a pointer to a structure containing the object. The pointer is
67 obtained by masking off the type and mark bits. 50 obtained by masking off the type and mark bits.
68 51
69 In the USE_MINIMAL_TAGBITS implementation, all 52 All pointer-based types are coalesced under a single type called
70 pointer-based types are coalesced under a single type called
71 Lisp_Type_Record. The type bits for this type are required 53 Lisp_Type_Record. The type bits for this type are required
72 by the implementation to be 00, just like the least 54 by the implementation to be 00, just like the least
73 significant bits of word-aligned struct pointers on 32-bit 55 significant bits of word-aligned struct pointers on 32-bit
74 hardware. Because of this, Lisp_Object pointers don't have 56 hardware. Because of this, Lisp_Object pointers don't have
75 to be masked and are full-sized. 57 to be masked and are full-sized.
76 58
77 In the non-USE_MINIMAL_TAGBITS implementation, the type and 59 There are no mark bits.
78 mark bits must be masked off and pointers are limited to 28
79 bits (really BITS_PER_EMACS_INT - GCTYPEBITS - 1 bits).
80
81 There are no mark bits in the USE_MINIMAL_TAGBITS implementation.
82 Integers and characters don't need to be marked. All other types 60 Integers and characters don't need to be marked. All other types
83 are lrecord-based, which means they get marked by incrementing 61 are lrecord-based, which means they get marked by incrementing
84 their ->implementation pointer. 62 their ->implementation pointer.
85 63
86 In the non-USE_MINIMAL_TAGBITS implementation, the markbit is stored
87 in the Lisp_Object itself. It is stored in the middle so that the
88 type bits can be obtained by simply shifting them.
89
90 Outside of garbage collection, all mark bits are always zero.
91
92 Here is a brief description of the following macros: 64 Here is a brief description of the following macros:
93 65
94 XMARKBIT Extract the mark bit (non-USE_MINIMAL_TAGBITS)
95 XMARK Set the mark bit of this Lisp_Object (non-USE_MINIMAL_TAGBITS)
96 XUNMARK Clear the mark bit of this Lisp_Object (non-USE_MINIMAL_TAGBITS)
97 XTYPE The type bits of a Lisp_Object 66 XTYPE The type bits of a Lisp_Object
98 XPNTRVAL The value bits of a Lisp_Object storing a pointer 67 XPNTRVAL The value bits of a Lisp_Object storing a pointer
99 XCHARVAL The value bits of a Lisp_Object storing a Emchar 68 XCHARVAL The value bits of a Lisp_Object storing a Emchar
100 XREALINT The value bits of a Lisp_Object storing an integer, signed 69 XREALINT The value bits of a Lisp_Object storing an integer, signed
101 XUINT The value bits of a Lisp_Object storing an integer, unsigned 70 XUINT The value bits of a Lisp_Object storing an integer, unsigned
102 INTP Non-zero if this Lisp_Object an integer? 71 INTP Non-zero if this Lisp_Object an integer?
103 Qzero Lisp Integer 0 72 Qzero Lisp Integer 0
104 EQ Non-zero if two Lisp_Objects are identical 73 EQ Non-zero if two Lisp_Objects are identical */
105 GC_EQ Version of EQ used during garbage collection 74
106 */
107 75
108 typedef EMACS_INT Lisp_Object; 76 typedef EMACS_INT Lisp_Object;
109 77
110 #ifdef USE_MINIMAL_TAGBITS 78 #define Lisp_Type_Int_Bit (Lisp_Type_Int_Even & Lisp_Type_Int_Odd)
111 79 #define make_obj(vartype, x) ((Lisp_Object) (x))
112 # define Lisp_Type_Int_Bit (Lisp_Type_Int_Even & Lisp_Type_Int_Odd) 80 #define make_int(x) ((Lisp_Object) (((x) << INT_GCBITS) | Lisp_Type_Int_Bit))
113 # define XUNMARK(x) DO_NOTHING 81 #define make_char(x) ((Lisp_Object) (((x) << GCBITS) | Lisp_Type_Char))
114 # define make_obj(vartype, x) ((Lisp_Object) (x)) 82 #define VALMASK (((1UL << VALBITS) - 1UL) << GCTYPEBITS)
115 # define make_int(x) ((Lisp_Object) (((x) << INT_GCBITS) | Lisp_Type_Int_Bit)) 83 #define XTYPE(x) ((enum Lisp_Type) (((EMACS_UINT)(x)) & ~VALMASK))
116 # define make_char(x) ((Lisp_Object) (((x) << GCBITS) | Lisp_Type_Char)) 84 #define XPNTRVAL(x) (x) /* This depends on Lisp_Type_Record == 0 */
117 # define VALMASK (((1UL << VALBITS) - 1UL) << GCTYPEBITS) 85 #define XCHARVAL(x) ((x) >> GCBITS)
118 # define XTYPE(x) ((enum Lisp_Type) (((EMACS_UINT)(x)) & ~VALMASK)) 86 #define XREALINT(x) ((x) >> INT_GCBITS)
119 # define XPNTRVAL(x) (x) /* This depends on Lisp_Type_Record == 0 */ 87 #define XUINT(x) ((EMACS_UINT)(x) >> INT_GCBITS)
120 # define XCHARVAL(x) ((x) >> GCBITS) 88 #define INTP(x) ((EMACS_UINT)(x) & Lisp_Type_Int_Bit)
121 # define GC_EQ(x,y) EQ (x,y) 89 #define INT_PLUS(x,y) ((x)+(y)-Lisp_Type_Int_Bit)
122 # define XREALINT(x) ((x) >> INT_GCBITS) 90 #define INT_MINUS(x,y) ((x)-(y)+Lisp_Type_Int_Bit)
123 # define XUINT(x) ((EMACS_UINT)(x) >> INT_GCBITS) 91 #define INT_PLUS1(x) INT_PLUS (x, make_int (1))
124 # define INTP(x) ((EMACS_UINT)(x) & Lisp_Type_Int_Bit) 92 #define INT_MINUS1(x) INT_MINUS (x, make_int (1))
125
126 #else /* !USE_MINIMAL_TAGBITS */
127
128 # define MARKBIT (1UL << VALBITS)
129 # define XMARKBIT(x) (((x) & MARKBIT) != 0)
130 # define XMARK(x) ((void) ((x) |= MARKBIT))
131 # define XUNMARK(x) ((void) ((x) &= ~MARKBIT))
132 # define make_obj(vartype, value) \
133 ((Lisp_Object) (((EMACS_UINT) (vartype) << (VALBITS + GCMARKBITS)) \
134 + ((EMACS_UINT) (value) & VALMASK)))
135 # define make_int(value) make_obj (Lisp_Type_Int, value)
136 # define make_char(value) make_obj (Lisp_Type_Char, value)
137 # define VALMASK ((1UL << VALBITS) - 1UL)
138 # define XTYPE(x) ((enum Lisp_Type) (((EMACS_UINT)(x)) >> (VALBITS + GCMARKBITS)))
139 # define XPNTRVAL(x) ((x) & VALMASK)
140 # define XCHARVAL(x) XPNTRVAL(x)
141 # define GC_EQ(x,y) (((x) & ~MARKBIT) == ((y) & ~MARKBIT))
142 # define XREALINT(x) (((x) << INT_GCBITS) >> INT_GCBITS)
143 # define XUINT(x) ((EMACS_UINT) ((x) & VALMASK))
144 # define INTP(x) (XTYPE (x) == Lisp_Type_Int)
145
146 #endif /* !USE_MINIMAL_TAGBITS */
147 93
148 #define Qzero make_int (0) 94 #define Qzero make_int (0)
149 #define Qnull_pointer ((Lisp_Object) 0) 95 #define Qnull_pointer ((Lisp_Object) 0)
150 #define XGCTYPE(x) XTYPE(x)
151 #define EQ(x,y) ((x) == (y)) 96 #define EQ(x,y) ((x) == (y))
152 #define XSETINT(var, value) ((void) ((var) = make_int (value))) 97 #define XSETINT(var, value) ((void) ((var) = make_int (value)))
153 #define XSETCHAR(var, value) ((void) ((var) = make_char (value))) 98 #define XSETCHAR(var, value) ((void) ((var) = make_char (value)))
154 #define XSETOBJ(var, vartype, value) ((void) ((var) = make_obj (vartype, value))) 99 #define XSETOBJ(var, vartype, value) ((void) ((var) = make_obj (vartype, value)))
155 100
156 /* Convert between a (void *) and a Lisp_Object, as when the 101 /* Convert between a (void *) and a Lisp_Object, as when the
157 Lisp_Object is passed to a toolkit callback function */ 102 Lisp_Object is passed to a toolkit callback function */
158 #define VOID_TO_LISP(larg,varg) ((void) ((larg) = ((Lisp_Object) (varg)))) 103 #define VOID_TO_LISP(larg,varg) ((void) ((larg) = ((Lisp_Object) (varg))))
159 #define CVOID_TO_LISP VOID_TO_LISP 104 #define CVOID_TO_LISP VOID_TO_LISP
160 #define LISP_TO_VOID(larg) ((void *) (larg)) 105 #define LISP_TO_VOID(larg) ((void *) (larg))
161 #define LISP_TO_CVOID(varg) ((CONST void *) (larg)) 106 #define LISP_TO_CVOID(varg) ((const void *) (larg))
162 107
163 /* Convert a Lisp_Object into something that can't be used as an 108 /* Convert a Lisp_Object into something that can't be used as an
164 lvalue. Useful for type-checking. */ 109 lvalue. Useful for type-checking. */
165 #define NON_LVALUE(larg) ((larg) + 0) 110 #define NON_LVALUE(larg) ((larg) + 0)