1 ;;;; type-based constants
3 ;;;; This software is part of the SBCL system. See the README file for
6 ;;;; This software is derived from the CMU CL system, which was
7 ;;;; written at Carnegie Mellon University and released into the
8 ;;;; public domain. The software is in the public domain and is
9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
10 ;;;; files for more information.
14 ;;; Tags for the main low-level types are stored in the low n (usually three)
15 ;;; bits to identify the type of a machine word. Certain constraints
17 ;;; * EVEN-FIXNUM-LOWTAG and ODD-FIXNUM-LOWTAG must be 0 and 4: code
18 ;;; which shifts left two places to convert raw integers to tagged
19 ;;; fixnums is ubiquitous.
20 ;;; * LIST-POINTER-LOWTAG + N-WORD-BYTES = OTHER-POINTER-LOWTAG: NIL
21 ;;; is both a cons and a symbol (at the same address) and depends on this.
22 ;;; See the definition of SYMBOL in objdef.lisp
23 ;;; * OTHER-POINTER-LOWTAG > 4: Some code in the SPARC backend,
24 ;;; which uses bit 2 of the ALLOC register to indicate that
25 ;;; PSEUDO-ATOMIC is on, doesn't strip the low bits of reg_ALLOC
26 ;;; before ORing in OTHER-POINTER-LOWTAG within a PSEUDO-ATOMIC
28 ;;; * OTHER-IMMEDIATE-0-LOWTAG are spaced 4 apart: various code wants to
29 ;;; iterate through these
30 ;;; * Allocation code on Alpha wants lowtags for heap-allocated
31 ;;; objects to be odd.
32 ;;; (These are just the ones we know about as of sbcl-0.7.1.22. There
33 ;;; might easily be more, since these values have stayed highly
34 ;;; constrained for more than a decade, an inviting target for
35 ;;; inventive abstraction-phobic maintainers.:-)
36 (eval-when (:compile-toplevel
:load-toplevel
:execute
)
37 ;; The EVAL-WHEN is necessary (at least for Lispworks), because the
38 ;; second DEFENUM uses the value of OTHER-IMMEDIATE-0-LOWTAG, which is
39 ;; defined in the first DEFENUM. -- AL 20000216
40 #!+#.
(cl:if
(cl:= 64 sb
!vm
:n-word-bits
) '(and) '(or))
43 instance-pointer-lowtag
44 other-immediate-0-lowtag
46 pad1-lowtag pad2-lowtag
47 other-immediate-1-lowtag
51 other-immediate-2-lowtag
55 other-immediate-3-lowtag
57 #!+#.
(cl:if
(cl:= 32 sb
!vm
:n-word-bits
) '(and) '(or))
60 instance-pointer-lowtag
61 other-immediate-0-lowtag
65 other-immediate-1-lowtag
66 other-pointer-lowtag
))
68 (def!constant nil-value
69 (+ static-space-start n-word-bytes other-pointer-lowtag
))
71 ;;; the heap types, stored in 8 bits of the header of an object on the
72 ;;; heap, to identify the type of the heap object (which'll be at
73 ;;; least two machine words, often more)
75 ;;; Note: the order specified here is not critical for correctness,
76 ;;; but (FIXME) with %TEST-HEADERS as currently defined, BIGNUM must
77 ;;; be first, and COMPLEX-ARRAY must be last.
79 ;;; However, for efficiency, we prefer contiguous sets of widetags for
80 ;;; "similar" objects, so that type checking can be done with a range
81 ;;; check, rather than several individual checks.
83 ;;; * BIGNUM + RATIO (+ FIXNUM) = RATIONAL
85 ;;; * SINGLE-FLOAT + DOUBLE-FLOAT + LONG-FLOAT = FLOAT
87 ;;; * RATIONAL + FLOAT = REAL
89 ;;; * (FIXME: COMPLEX example, which needs fixing anyway -- see
90 ;;; UPGRADED-COMPLEX-PART-TYPE)
92 ;;; * SIMPLE-ARRAY-* = (SIMPLE-ARRAY * (*))
94 ;;; * SIMPLE-ARRAY-NIL + SIMPLE-BASE-STRING = SIMPLE-STRING
96 ;;; * SIMPLE-ARRAY + COMPLEX-ARRAYOID = (SATISFIES ARRAY-HEADER-P)
99 ;;; sufficient care we can cause extra combinations to appear with
100 ;;; differences in only one bit, permitting a more efficient type
101 ;;; test. As an example, if SIMPLE-BASE-STRING = 0xA6 and
102 ;;; COMPLEX-BASE-STRING = 0xE6, then the type test for BASE-STRING is
104 ;;; AND tag, ~0x40, tag
105 ;;; ANDcc tag, 0xA6, tag
108 ;;; rather than two separate tests and jumps
109 (defenum (;; The first widetag must be greater than SB!VM:LOWTAG-LIMIT
110 ;; otherwise code in generic/early-type-vops will suffer
111 ;; a long, horrible death. --njf, 2004-08-09
112 :start
(+ (ash 1 n-lowtag-bits
) other-immediate-0-lowtag
)
114 ;; NOTE: the binary numbers off to the side are only valid for 32-bit
115 ;; ports; add #b1000 if you want to know the values for 64-bit ports.
116 ;; And note that the numbers get a little scrambled further down.
118 bignum-widetag
; 00001010
119 ratio-widetag
; 00001110
120 single-float-widetag
; 00010010
121 double-float-widetag
; 00010110
122 complex-widetag
; 00011010
123 complex-single-float-widetag
; 00011110
124 complex-double-float-widetag
; 00100010
126 code-header-widetag
; 00100110
128 simple-fun-header-widetag
; 00101010
129 closure-header-widetag
; 00101110
130 funcallable-instance-header-widetag
; 00110010
132 return-pc-header-widetag
; 00110110
133 value-cell-header-widetag
; 00111010
134 symbol-header-widetag
; 00111110
135 character-widetag
; 01000010
136 sap-widetag
; 01000110
137 unbound-marker-widetag
; 01001010
138 weak-pointer-widetag
; 01001110
139 instance-header-widetag
; 01010010
140 fdefn-widetag
; 01010110
142 no-tls-value-marker-widetag
; 01011010
143 #!-
(and sb-lutex sb-thread
)
145 #!+(and sb-lutex sb-thread
)
146 lutex-widetag
; 01011110
150 sse-pack-widetag
; 01100010
151 unused03-widetag
; 01100110
152 unused04-widetag
; 01101010
153 unused05-widetag
; 01101110
154 unused06-widetag
; 01110010
155 unused07-widetag
; 01110110
156 #!+#.
(cl:if
(cl:= 32 sb
!vm
:n-word-bits
) '(and) '(or))
157 unused08-widetag
; 01111010
158 #!+#.
(cl:if
(cl:= 32 sb
!vm
:n-word-bits
) '(and) '(or))
159 unused09-widetag
; 01111110
161 #!+#.
(cl:if
(cl:= 32 sb
!vm
:n-word-bits
) '(and) '(or))
162 unused10-widetag
; 10000010
163 #!+#.
(cl:if
(cl:= 32 sb
!vm
:n-word-bits
) '(and) '(or))
164 unused11-widetag
; 10000110
166 simple-array-unsigned-byte-2-widetag
; 10001010
167 simple-array-unsigned-byte-4-widetag
; 10001110
168 simple-array-unsigned-byte-7-widetag
; 10010010
169 simple-array-unsigned-byte-8-widetag
; 10010110
170 simple-array-unsigned-byte-15-widetag
; 10011010
171 simple-array-unsigned-byte-16-widetag
; 10011110
172 simple-array-nil-widetag
; 10100010
173 simple-base-string-widetag
; 10100110
174 #!+sb-unicode simple-character-string-widetag
175 simple-bit-vector-widetag
; 10101010
176 simple-vector-widetag
; 10101110
177 #!+#.
(cl:if
(cl:= 32 sb
!vm
:n-word-bits
) '(and) '(or))
178 simple-array-unsigned-byte-29-widetag
; 10110010
179 simple-array-unsigned-byte-31-widetag
; 10110110
180 simple-array-unsigned-byte-32-widetag
; 10111010
181 #!+#.
(cl:if
(cl:= 64 sb
!vm
:n-word-bits
) '(and) '(or))
182 simple-array-unsigned-byte-60-widetag
183 #!+#.
(cl:if
(cl:= 64 sb
!vm
:n-word-bits
) '(and) '(or))
184 simple-array-unsigned-byte-63-widetag
185 #!+#.
(cl:if
(cl:= 64 sb
!vm
:n-word-bits
) '(and) '(or))
186 simple-array-unsigned-byte-64-widetag
187 simple-array-signed-byte-8-widetag
; 10111110
188 simple-array-signed-byte-16-widetag
; 11000010
189 #!+#.
(cl:if
(cl:= 32 sb
!vm
:n-word-bits
) '(and) '(or))
190 simple-array-signed-byte-30-widetag
; 11000110
191 simple-array-signed-byte-32-widetag
; 11001010
192 #!+#.
(cl:if
(cl:= 64 sb
!vm
:n-word-bits
) '(and) '(or))
193 simple-array-signed-byte-61-widetag
194 #!+#.
(cl:if
(cl:= 64 sb
!vm
:n-word-bits
) '(and) '(or))
195 simple-array-signed-byte-64-widetag
196 simple-array-single-float-widetag
; 11001110
197 simple-array-double-float-widetag
; 11010010
198 simple-array-complex-single-float-widetag
; 11010110
199 simple-array-complex-double-float-widetag
; 11011010
200 simple-array-widetag
; 11011110
201 complex-vector-nil-widetag
; 11100010
202 complex-base-string-widetag
; 11100110
203 #!+sb-unicode complex-character-string-widetag
204 complex-bit-vector-widetag
; 11101010
205 complex-vector-widetag
; 11101110
206 complex-array-widetag
; 11110010
208 #!+#.
(cl:if
(cl:= 32 sb
!vm
:n-word-bits
) '(and) '(or))
209 unused12-widetag
; 11110110
210 #!+(and #.
(cl:if
(cl:= 32 sb
!vm
:n-word-bits
) '(and) '(or))
212 unused13-widetag
; 11111010
213 #!+(and #.
(cl:if
(cl:= 32 sb
!vm
:n-word-bits
) '(and) '(or))
215 unused14-widetag
; 11111110
218 ;;; the different vector subtypes
220 vector-normal-subtype
221 vector-unused-subtype
222 vector-valid-hashing-subtype
)