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 natural width of a machine word (as seen in e.g. register width,
32 (def!constant n-machine-word-bits 32)
34 ;;; the number of bits per byte, where a byte is the smallest
35 ;;; addressable object
36 (def!constant n-byte-bits 8)
38 ;;; the number of bits to shift between word addresses and byte addresses
39 (def!constant word-shift (1- (integer-length (/ n-word-bits n-byte-bits))))
41 ;;; the number of bytes in a word
42 (def!constant n-word-bytes (/ n-word-bits n-byte-bits))
44 (def!constant float-sign-shift 31)
46 ;;; comment from CMU CL:
47 ;;; These values were taken from the alpha code. The values for
48 ;;; bias and exponent min/max are not the same as shown in the 486 book.
49 ;;; They may be correct for how Python uses them.
50 (def!constant single-float-bias 126) ; Intel says 127.
51 (defconstant-eqx single-float-exponent-byte (byte 8 23) #'equalp)
52 (defconstant-eqx single-float-significand-byte (byte 23 0) #'equalp)
53 ;;; comment from CMU CL:
54 ;;; The 486 book shows the exponent range -126 to +127. The Lisp
55 ;;; code that uses these values seems to want already biased numbers.
56 (def!constant single-float-normal-exponent-min 1)
57 (def!constant single-float-normal-exponent-max 254)
58 (def!constant single-float-hidden-bit (ash 1 23))
59 (def!constant single-float-trapping-nan-bit (ash 1 22))
61 (def!constant double-float-bias 1022)
62 (defconstant-eqx double-float-exponent-byte (byte 11 20) #'equalp)
63 (defconstant-eqx double-float-significand-byte (byte 20 0) #'equalp)
64 (def!constant double-float-normal-exponent-min 1)
65 (def!constant double-float-normal-exponent-max #x7FE)
66 (def!constant double-float-hidden-bit (ash 1 20))
67 (def!constant double-float-trapping-nan-bit (ash 1 19))
69 (def!constant long-float-bias 16382)
70 (defconstant-eqx long-float-exponent-byte (byte 15 0) #'equalp)
71 (defconstant-eqx long-float-significand-byte (byte 31 0) #'equalp)
72 (def!constant long-float-normal-exponent-min 1)
73 (def!constant long-float-normal-exponent-max #x7FFE)
74 (def!constant long-float-hidden-bit (ash 1 31)) ; actually not hidden
75 (def!constant long-float-trapping-nan-bit (ash 1 30))
77 (def!constant single-float-digits
78 (+ (byte-size single-float-significand-byte) 1))
80 (def!constant double-float-digits
81 (+ (byte-size double-float-significand-byte) n-word-bits 1))
83 (def!constant long-float-digits
84 (+ (byte-size long-float-significand-byte) n-word-bits 1))
86 ;;; pfw -- from i486 microprocessor programmer's reference manual
87 (def!constant float-invalid-trap-bit (ash 1 0))
88 (def!constant float-denormal-trap-bit (ash 1 1))
89 (def!constant float-divide-by-zero-trap-bit (ash 1 2))
90 (def!constant float-overflow-trap-bit (ash 1 3))
91 (def!constant float-underflow-trap-bit (ash 1 4))
92 (def!constant float-inexact-trap-bit (ash 1 5))
94 (def!constant float-round-to-nearest 0)
95 (def!constant float-round-to-negative 1)
96 (def!constant float-round-to-positive 2)
97 (def!constant float-round-to-zero 3)
99 (defconstant-eqx float-rounding-mode (byte 2 10) #'equalp)
100 (defconstant-eqx float-sticky-bits (byte 6 16) #'equalp)
101 (defconstant-eqx float-traps-byte (byte 6 0) #'equalp)
102 (defconstant-eqx float-exceptions-byte (byte 6 16) #'equalp)
103 (defconstant-eqx float-precision-control (byte 2 8) #'equalp)
104 (def!constant float-fast-bit 0) ; no fast mode on x86
106 ;;;; description of the target address space
108 ;;; where to put the different spaces
110 ;;; Note: Mostly these values are black magic, inherited from CMU CL
111 ;;; without any documentation. However, there were a few explanatory
112 ;;; comments in the CMU CL sources:
114 ;;; ** The space 0x08000000-0x10000000 is "C program and memory allocation".
115 ;;; ** The space 0x40000000-0x48000000 is reserved for shared libs.
116 ;;; ** The space >0xE0000000 is "C stack - Alien stack".
118 ;;; ** The space 0x0E000000-0x10000000 is "Foreign segment".
119 ;;; ** The space 0x20000000-0x30000000 is reserved for shared libs.
120 ;;; And there have been some changes since the fork from CMU CL:
121 ;;; * The OpenBSD port is new since the fork. We started with
122 ;;; the FreeBSD address map, which actually worked until the
123 ;;; Alpha port patches, for reasons which in retrospect are rather
124 ;;; mysterious. After the Alpha port patches were added, the
125 ;;; OpenBSD port suffered memory corruption problems. While
126 ;;; debugging those, it was discovered that src/runtime/trymap
127 ;;; failed for the control stack region #x40000000-#x47fff000.
128 ;;; After the control stack was moved upward out of this region
129 ;;; (stealing some bytes from dynamic space) the problems went
131 ;;; * The FreeBSD STATIC-SPACE-START value was bumped up from
132 ;;; #x28000000 to #x30000000 when FreeBSD ld.so dynamic linking
133 ;;; support was added for FreeBSD ca. 20000910. This was to keep from
134 ;;; stomping on an address range that the dynamic libraries want to
135 ;;; use. (They want to use this address range even if we try to
136 ;;; reserve it with a call to validate() as the first operation in
142 (def!constant read-only-space-start #x01000000)
143 (def!constant read-only-space-end #x037ff000)
145 (def!constant static-space-start #x05000000)
146 (def!constant static-space-end #x07fff000)
148 (def!constant dynamic-space-start #x09000000)
149 (def!constant dynamic-space-end #x29000000))
154 (def!constant read-only-space-start #x10000000)
155 (def!constant read-only-space-end #x1ffff000)
157 (def!constant static-space-start
158 #!+freebsd #x30000000
159 #!+openbsd #x28000000)
160 (def!constant static-space-end #x37fff000)
162 (def!constant dynamic-space-start
163 #!+freebsd #x48000000
164 #!+openbsd #x50000000)
165 (def!constant dynamic-space-end #x88000000))
167 ;;; Given that NIL is the first thing allocated in static space, we
168 ;;; know its value at compile time:
169 (def!constant nil-value (+ static-space-start #xb))
171 ;;;; other miscellaneous constants
173 (defenum (:suffix -trap :start 8)
180 single-step-breakpoint)
181 ;;; FIXME: It'd be nice to replace all the DEFENUMs with something like
182 ;;; (WITH-DEF-ENUM (:START 8)
183 ;;; (DEF-ENUM HALT-TRAP)
184 ;;; (DEF-ENUM PENDING-INTERRUPT-TRAP)
186 ;;; for the benefit of anyone doing a lexical search for definitions
187 ;;; of these symbols.
189 (defenum (:prefix object-not- :suffix -trap :start 16)
193 (defenum (:prefix trace-table-)
201 ;;; These symbols are loaded into static space directly after NIL so
202 ;;; that the system can compute their address by adding a constant
205 ;;; The fdefn objects for the static functions are loaded into static
206 ;;; space directly after the static symbols. That way, the raw-addr
207 ;;; can be loaded directly out of them by indirecting relative to NIL.
209 ;;; pfw X86 doesn't have enough registers to keep these things there.
210 ;;; Note these spaces grow from low to high addresses.
211 (defvar *allocation-pointer*)
212 (defvar *binding-stack-pointer*)
214 ;;; FIXME: !COLD-INIT probably doesn't need
215 ;;; to be in the static symbols table any more.
216 (defparameter *static-symbols*
219 ;; The C startup code must fill these in.
222 ;; functions that the C code needs to call. When adding to this list,
223 ;; also add a `frob' form in genesis.lisp finish-symbols.
225 sb!kernel::internal-error
226 sb!kernel::control-stack-exhausted-error
227 sb!di::handle-breakpoint
232 ;; Note that these are FIXNUM word counts, not (as one might
233 ;; expect) byte counts or SAPs. The reason seems to be that by
234 ;; representing them this way, we can avoid consing bignums.
236 *read-only-space-free-pointer*
237 *static-space-free-pointer*
238 *initial-dynamic-space-free-pointer*
240 ;; things needed for non-local exit
241 *current-catch-block*
242 *current-unwind-protect-block*
245 ;; interrupt handling
246 *pseudo-atomic-atomic*
247 *pseudo-atomic-interrupted*
248 sb!unix::*interrupts-enabled*
249 sb!unix::*interrupt-pending*
250 *free-interrupt-context-index*
253 sb!thread::*foreground-thread-stack*
256 *binding-stack-pointer*
257 *binding-stack-start*
258 *control-stack-start*
261 ;; the floating point constants
266 ;; The following are all long-floats.
275 ;; The ..SLOT-UNBOUND.. symbol is static in order to optimise the
276 ;; common slot unbound check.
278 ;; FIXME: In SBCL, the CLOS code has become sufficiently tightly
279 ;; integrated into the system that it'd probably make sense to use
280 ;; the ordinary unbound marker for this.
281 sb!pcl::..slot-unbound..))
283 (defparameter *static-funs*
294 sb!kernel:two-arg-and
295 sb!kernel:two-arg-ior
296 sb!kernel:two-arg-xor
297 sb!kernel:two-arg-gcd
298 sb!kernel:two-arg-lcm))
300 ;;;; stuff added by jrd
302 ;;; FIXME: Is this used? Delete it or document it.
303 ;;; cf the sparc PARMS.LISP
304 (defparameter *assembly-unit-length* 8)