1 ;;;; This file contains some parameterizations of various VM
2 ;;;; attributes for the x86. This file is separate from other stuff so
3 ;;;; that it can be compiled and loaded earlier.
5 ;;;; This software is part of the SBCL system. See the README file for
8 ;;;; This software is derived from the CMU CL system, which was
9 ;;;; written at Carnegie Mellon University and released into the
10 ;;;; public domain. The software is in the public domain and is
11 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
12 ;;;; files for more information.
16 ;;; ### Note: we simultaneously use ``word'' to mean a 32 bit quantity
17 ;;; and a 16 bit quantity depending on context. This is because Intel
18 ;;; insists on calling 16 bit things words and 32 bit things
19 ;;; double-words (or dwords). Therefore, in the instruction definition
20 ;;; and register specs, we use the Intel convention. But whenever we
21 ;;; are talking about stuff the rest of the lisp system might be
22 ;;; interested in, we use ``word'' to mean the size of a descriptor
23 ;;; object, which is 32 bits.
25 ;;;; machine architecture parameters
27 ;;; the number of bits per word, where a word holds one lisp descriptor
28 (def!constant n-word-bits 32)
30 ;;; the number of bits per byte, where a byte is the smallest
31 ;;; addressable object
32 (def!constant n-byte-bits 8)
34 ;;; the number of bits to shift between word addresses and byte addresses
35 (def!constant word-shift (1- (integer-length (/ n-word-bits n-byte-bits))))
37 ;;; the number of bytes in a word
38 (def!constant n-word-bytes (/ n-word-bits n-byte-bits))
40 (def!constant float-sign-shift 31)
42 ;;; comment from CMU CL:
43 ;;; These values were taken from the alpha code. The values for
44 ;;; bias and exponent min/max are not the same as shown in the 486 book.
45 ;;; They may be correct for how Python uses them.
46 (def!constant single-float-bias 126) ; Intel says 127.
47 (defconstant-eqx single-float-exponent-byte (byte 8 23) #'equalp)
48 (defconstant-eqx single-float-significand-byte (byte 23 0) #'equalp)
49 ;;; comment from CMU CL:
50 ;;; The 486 book shows the exponent range -126 to +127. The Lisp
51 ;;; code that uses these values seems to want already biased numbers.
52 (def!constant single-float-normal-exponent-min 1)
53 (def!constant single-float-normal-exponent-max 254)
54 (def!constant single-float-hidden-bit (ash 1 23))
55 (def!constant single-float-trapping-nan-bit (ash 1 22))
57 (def!constant double-float-bias 1022)
58 (defconstant-eqx double-float-exponent-byte (byte 11 20) #'equalp)
59 (defconstant-eqx double-float-significand-byte (byte 20 0) #'equalp)
60 (def!constant double-float-normal-exponent-min 1)
61 (def!constant double-float-normal-exponent-max #x7FE)
62 (def!constant double-float-hidden-bit (ash 1 20))
63 (def!constant double-float-trapping-nan-bit (ash 1 19))
65 (def!constant long-float-bias 16382)
66 (defconstant-eqx long-float-exponent-byte (byte 15 0) #'equalp)
67 (defconstant-eqx long-float-significand-byte (byte 31 0) #'equalp)
68 (def!constant long-float-normal-exponent-min 1)
69 (def!constant long-float-normal-exponent-max #x7FFE)
70 (def!constant long-float-hidden-bit (ash 1 31)) ; actually not hidden
71 (def!constant long-float-trapping-nan-bit (ash 1 30))
73 (def!constant single-float-digits
74 (+ (byte-size single-float-significand-byte) 1))
76 (def!constant double-float-digits
77 (+ (byte-size double-float-significand-byte) n-word-bits 1))
79 (def!constant long-float-digits
80 (+ (byte-size long-float-significand-byte) n-word-bits 1))
82 ;;; pfw -- from i486 microprocessor programmer's reference manual
83 (def!constant float-invalid-trap-bit (ash 1 0))
84 (def!constant float-denormal-trap-bit (ash 1 1))
85 (def!constant float-divide-by-zero-trap-bit (ash 1 2))
86 (def!constant float-overflow-trap-bit (ash 1 3))
87 (def!constant float-underflow-trap-bit (ash 1 4))
88 (def!constant float-inexact-trap-bit (ash 1 5))
90 (def!constant float-round-to-nearest 0)
91 (def!constant float-round-to-negative 1)
92 (def!constant float-round-to-positive 2)
93 (def!constant float-round-to-zero 3)
95 (defconstant-eqx float-rounding-mode (byte 2 10) #'equalp)
96 (defconstant-eqx float-sticky-bits (byte 6 16) #'equalp)
97 (defconstant-eqx float-traps-byte (byte 6 0) #'equalp)
98 (defconstant-eqx float-exceptions-byte (byte 6 16) #'equalp)
99 (defconstant-eqx float-precision-control (byte 2 8) #'equalp)
100 (def!constant float-fast-bit 0) ; no fast mode on x86
102 ;;;; description of the target address space
104 ;;; where to put the different spaces
106 ;;; Note: Mostly these values are black magic, inherited from CMU CL
107 ;;; without any documentation. However, there were a few explanatory
108 ;;; comments in the CMU CL sources:
110 ;;; ** The space 0x08000000-0x10000000 is "C program and memory allocation".
111 ;;; ** The space 0x40000000-0x48000000 is reserved for shared libs.
112 ;;; ** The space >0xE0000000 is "C stack - Alien stack".
114 ;;; ** The space 0x0E000000-0x10000000 is "Foreign segment".
115 ;;; ** The space 0x20000000-0x30000000 is reserved for shared libs.
116 ;;; And there have been some changes since the fork from CMU CL:
117 ;;; * The OpenBSD port is new since the fork. We started with
118 ;;; the FreeBSD address map, which actually worked until the
119 ;;; Alpha port patches, for reasons which in retrospect are rather
120 ;;; mysterious. After the Alpha port patches were added, the
121 ;;; OpenBSD port suffered memory corruption problems. While
122 ;;; debugging those, it was discovered that src/runtime/trymap
123 ;;; failed for the control stack region #x40000000-#x47fff000.
124 ;;; After the control stack was moved upward out of this region
125 ;;; (stealing some bytes from dynamic space) the problems went
127 ;;; * The FreeBSD STATIC-SPACE-START value was bumped up from
128 ;;; #x28000000 to #x30000000 when FreeBSD ld.so dynamic linking
129 ;;; support was added for FreeBSD ca. 20000910. This was to keep from
130 ;;; stomping on an address range that the dynamic libraries want to
131 ;;; use. (They want to use this address range even if we try to
132 ;;; reserve it with a call to validate() as the first operation in
138 (def!constant read-only-space-start #x01000000)
139 (def!constant read-only-space-end #x037ff000)
141 (def!constant static-space-start #x05000000)
142 (def!constant static-space-end #x07fff000)
144 (def!constant dynamic-space-start #x09000000)
145 (def!constant dynamic-space-end #x29000000)
147 (def!constant control-stack-start #x50000000)
148 (def!constant control-stack-end #x57fff000)
150 (def!constant binding-stack-start #x60000000)
151 (def!constant binding-stack-end #x67fff000)
152 (def!constant alternate-signal-stack-start #x58000000))
157 (def!constant read-only-space-start #x10000000)
158 (def!constant read-only-space-end #x1ffff000)
160 (def!constant static-space-start
161 #!+freebsd #x30000000
162 #!+openbsd #x28000000)
163 (def!constant static-space-end #x37fff000)
165 (def!constant binding-stack-start #x38000000)
166 (def!constant binding-stack-end #x3ffff000)
168 (def!constant control-stack-start
169 #!+freebsd #x40000000
170 #!+openbsd #x48000000)
171 (def!constant control-stack-end
172 #!+freebsd #x43fff000
173 #!+openbsd #x4bfff000)
174 (def!constant dynamic-space-start
175 #!+freebsd #x48000000
176 #!+openbsd #x50000000)
177 (def!constant dynamic-space-end #x88000000)
178 (def!constant alternate-signal-stack-start
179 #!+freebsd #x44000000
180 #!+openbsd #x4c000000))
183 ;;; don't need alternate-signal-stack-end : it's -start+SIGSTKSZ
186 ;;; Given that NIL is the first thing allocated in static space, we
187 ;;; know its value at compile time:
188 (def!constant nil-value (+ static-space-start #xb))
190 ;;;; other miscellaneous constants
192 (defenum (:suffix -trap :start 8)
199 single-step-breakpoint)
200 ;;; FIXME: It'd be nice to replace all the DEFENUMs with something like
201 ;;; (WITH-DEF-ENUM (:START 8)
202 ;;; (DEF-ENUM HALT-TRAP)
203 ;;; (DEF-ENUM PENDING-INTERRUPT-TRAP)
205 ;;; for the benefit of anyone doing a lexical search for definitions
206 ;;; of these symbols.
208 (defenum (:prefix object-not- :suffix -trap :start 16)
212 (defenum (:prefix trace-table-)
220 ;;; These symbols are loaded into static space directly after NIL so
221 ;;; that the system can compute their address by adding a constant
224 ;;; The fdefn objects for the static functions are loaded into static
225 ;;; space directly after the static symbols. That way, the raw-addr
226 ;;; can be loaded directly out of them by indirecting relative to NIL.
228 ;;; pfw X86 doesn't have enough registers to keep these things there.
229 ;;; Note these spaces grow from low to high addresses.
230 (defvar *allocation-pointer*)
231 (defvar *binding-stack-pointer*)
233 ;;; FIXME: !COLD-INIT probably doesn't need
234 ;;; to be in the static symbols table any more.
235 (defparameter *static-symbols*
238 ;; The C startup code must fill these in.
241 ;; functions that the C code needs to call. When adding to this list,
242 ;; also add a `frob' form in genesis.lisp finish-symbols.
244 sb!kernel::internal-error
245 sb!kernel::control-stack-exhausted-error
246 sb!di::handle-breakpoint
251 ;; Note that these are FIXNUM word counts, not (as one might
252 ;; expect) byte counts or SAPs. The reason seems to be that by
253 ;; representing them this way, we can avoid consing bignums.
255 *read-only-space-free-pointer*
256 *static-space-free-pointer*
257 *initial-dynamic-space-free-pointer*
259 ;; things needed for non-local exit
260 *current-catch-block*
261 *current-unwind-protect-block*
264 ;; interrupt handling
265 *pseudo-atomic-atomic*
266 *pseudo-atomic-interrupted*
267 sb!unix::*interrupts-enabled*
268 sb!unix::*interrupt-pending*
269 *free-interrupt-context-index*
272 *binding-stack-pointer*
274 ;; the floating point constants
279 ;; The following are all long-floats.
288 ;; The ..SLOT-UNBOUND.. symbol is static in order to optimise the
289 ;; common slot unbound check.
291 ;; FIXME: In SBCL, the CLOS code has become sufficiently tightly
292 ;; integrated into the system that it'd probably make sense to use
293 ;; the ordinary unbound marker for this.
294 sb!pcl::..slot-unbound..))
296 (defparameter *static-funs*
307 sb!kernel:two-arg-and
308 sb!kernel:two-arg-ior
309 sb!kernel:two-arg-xor
310 sb!kernel:two-arg-gcd
311 sb!kernel:two-arg-lcm))
313 ;;;; stuff added by jrd
315 ;;; FIXME: Is this used? Delete it or document it.
316 ;;; cf the sparc PARMS.LISP
317 (defparameter *assembly-unit-length* 8)