src/compiler/x86/parms.lisp

   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.
   4
   5 ;;;; This software is part of the SBCL system. See the README file for
   6 ;;;; more information.
   7 ;;;;
   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.
  13
  14 (in-package "SB!VM")
  15
  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.
  24 \f
  25 ;;;; machine architecture parameters
  26
  27 ;;; the number of bits per word, where a word holds one lisp descriptor
  28 (def!constant n-word-bits 32)
  29
  30 ;;; the number of bits per byte, where a byte is the smallest
  31 ;;; addressable object
  32 (def!constant n-byte-bits 8)
  33
  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))))
  36
  37 ;;; the number of bytes in a word
  38 (def!constant n-word-bytes (/ n-word-bits n-byte-bits))
  39
  40 (def!constant float-sign-shift 31)
  41
  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))
  56
  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))
  64
  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))
  72
  73 (def!constant single-float-digits
  74   (+ (byte-size single-float-significand-byte) 1))
  75
  76 (def!constant double-float-digits
  77   (+ (byte-size double-float-significand-byte) n-word-bits 1))
  78
  79 (def!constant long-float-digits
  80   (+ (byte-size long-float-significand-byte) n-word-bits 1))
  81
  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))
  89
  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)
  94
  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
 101 \f
 102 ;;;; description of the target address space
 103
 104 ;;; where to put the different spaces
 105 ;;;
 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:
 109 ;;;   * On Linux,
 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".
 113 ;;;   * On FreeBSD,
 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
 126 ;;;     away.
 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
 133 ;;;     main().)
 134
 135 #!+linux
 136 (progn
 137
 138   (def!constant read-only-space-start #x01000000)
 139   (def!constant read-only-space-end   #x037ff000)
 140
 141   (def!constant static-space-start    #x05000000)
 142   (def!constant static-space-end      #x07fff000)
 143
 144   (def!constant dynamic-space-start   #x09000000)
 145   (def!constant dynamic-space-end     #x29000000)
 146
 147   (def!constant alternate-signal-stack-start #x58000000))
 148
 149 #!+bsd
 150 (progn
 151
 152   (def!constant read-only-space-start #x10000000)
 153   (def!constant read-only-space-end   #x1ffff000)
 154
 155   (def!constant static-space-start
 156     #!+freebsd #x30000000
 157     #!+openbsd #x28000000)
 158   (def!constant static-space-end      #x37fff000)
 159
 160   (def!constant dynamic-space-start
 161     #!+freebsd                             #x48000000
 162     #!+openbsd                             #x50000000)
 163   (def!constant dynamic-space-end          #x88000000)
 164   (def!constant alternate-signal-stack-start
 165       #!+freebsd #x44000000
 166       #!+openbsd #x4c000000))
 167
 168
 169 ;;; don't need alternate-signal-stack-end : it's -start+SIGSTKSZ
 170
 171
 172 ;;; Given that NIL is the first thing allocated in static space, we
 173 ;;; know its value at compile time:
 174 (def!constant nil-value (+ static-space-start #xb))
 175 \f
 176 ;;;; other miscellaneous constants
 177
 178 (defenum (:suffix -trap :start 8)
 179   halt
 180   pending-interrupt
 181   error
 182   cerror
 183   breakpoint
 184   fun-end-breakpoint
 185   single-step-breakpoint)
 186 ;;; FIXME: It'd be nice to replace all the DEFENUMs with something like
 187 ;;;   (WITH-DEF-ENUM (:START 8)
 188 ;;;     (DEF-ENUM HALT-TRAP)
 189 ;;;     (DEF-ENUM PENDING-INTERRUPT-TRAP)
 190 ;;;     ..)
 191 ;;; for the benefit of anyone doing a lexical search for definitions
 192 ;;; of these symbols.
 193
 194 (defenum (:prefix object-not- :suffix -trap :start 16)
 195   list
 196   instance)
 197
 198 (defenum (:prefix trace-table-)
 199   normal
 200   call-site
 201   fun-prologue
 202   fun-epilogue)
 203 \f
 204 ;;;; static symbols
 205
 206 ;;; These symbols are loaded into static space directly after NIL so
 207 ;;; that the system can compute their address by adding a constant
 208 ;;; amount to NIL.
 209 ;;;
 210 ;;; The fdefn objects for the static functions are loaded into static
 211 ;;; space directly after the static symbols. That way, the raw-addr
 212 ;;; can be loaded directly out of them by indirecting relative to NIL.
 213 ;;;
 214 ;;; pfw X86 doesn't have enough registers to keep these things there.
 215 ;;;     Note these spaces grow from low to high addresses.
 216 (defvar *allocation-pointer*)
 217 (defvar *binding-stack-pointer*)
 218
 219 ;;; FIXME: !COLD-INIT probably doesn't need
 220 ;;; to be in the static symbols table any more.
 221 (defparameter *static-symbols*
 222   '(t
 223
 224     ;; The C startup code must fill these in.
 225     *posix-argv*
 226
 227     ;; functions that the C code needs to call.  When adding to this list,
 228     ;; also add a `frob' form in genesis.lisp finish-symbols.
 229     maybe-gc
 230     sb!kernel::internal-error
 231     sb!kernel::control-stack-exhausted-error
 232     sb!di::handle-breakpoint
 233     fdefinition-object
 234
 235     ;; free pointers
 236     ;;
 237     ;; Note that these are FIXNUM word counts, not (as one might
 238     ;; expect) byte counts or SAPs. The reason seems to be that by
 239     ;; representing them this way, we can avoid consing bignums.
 240     ;; -- WHN 2000-10-02
 241     *read-only-space-free-pointer*
 242     *static-space-free-pointer*
 243     *initial-dynamic-space-free-pointer*
 244
 245     ;; things needed for non-local exit
 246     *current-catch-block*
 247     *current-unwind-protect-block*
 248     *alien-stack*
 249
 250     ;; interrupt handling
 251     *pseudo-atomic-atomic*
 252     *pseudo-atomic-interrupted*
 253     sb!unix::*interrupts-enabled*
 254     sb!unix::*interrupt-pending*
 255     *free-interrupt-context-index*
 256
 257     *free-tls-index*
 258     sb!thread::*foreground-thread-stack*
 259
 260     *allocation-pointer*
 261     *binding-stack-pointer*
 262     *binding-stack-start*
 263     *control-stack-start*
 264     *control-stack-end*
 265
 266     ;; the floating point constants
 267     *fp-constant-0d0*
 268     *fp-constant-1d0*
 269     *fp-constant-0f0*
 270     *fp-constant-1f0*
 271     ;; The following are all long-floats.
 272     *fp-constant-0l0*
 273     *fp-constant-1l0*
 274     *fp-constant-pi*
 275     *fp-constant-l2t*
 276     *fp-constant-l2e*
 277     *fp-constant-lg2*
 278     *fp-constant-ln2*
 279
 280     ;; The ..SLOT-UNBOUND.. symbol is static in order to optimise the
 281     ;; common slot unbound check.
 282     ;;
 283     ;; FIXME: In SBCL, the CLOS code has become sufficiently tightly
 284     ;; integrated into the system that it'd probably make sense to use
 285     ;; the ordinary unbound marker for this.
 286     sb!pcl::..slot-unbound..))
 287
 288 (defparameter *static-funs*
 289   '(length
 290     sb!kernel:two-arg-+
 291     sb!kernel:two-arg--
 292     sb!kernel:two-arg-*
 293     sb!kernel:two-arg-/
 294     sb!kernel:two-arg-<
 295     sb!kernel:two-arg->
 296     sb!kernel:two-arg-=
 297     eql
 298     sb!kernel:%negate
 299     sb!kernel:two-arg-and
 300     sb!kernel:two-arg-ior
 301     sb!kernel:two-arg-xor
 302     sb!kernel:two-arg-gcd
 303     sb!kernel:two-arg-lcm))
 304 \f
 305 ;;;; stuff added by jrd
 306
 307 ;;; FIXME: Is this used? Delete it or document it.
 308 ;;; cf the sparc PARMS.LISP
 309 (defparameter *assembly-unit-length* 8)