src/compiler/arm/move.lisp

   1 ;;;; the ARM VM definition of operand loading/saving and the Move VOP
   2
   3 ;;;; This software is part of the SBCL system. See the README file for
   4 ;;;; more information.
   5 ;;;;
   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.
  11
  12 (in-package "SB!VM")
  13
  14 (defun lowest-set-bit-index (integer-value)
  15   (max 0 (1- (integer-length (logand integer-value (- integer-value))))))
  16
  17 ;; FIXME: This load-immediate-word stuff could me more clever. The
  18 ;; decision on loading positive or negative shouldn't depend on the sign
  19 ;; of the value, it should depend on the logcount of the two's complement
  20 ;; representation (or maybe an even smarter selection criterion).
  21
  22 (defun load-immediate-word (y val)
  23   (if (< val 0)
  24       (composite-immediate-instruction bic y y val :first-op mvn :first-no-source t :invert-y t)
  25       (composite-immediate-instruction orr y y val :first-op mov :first-no-source t)))
  26
  27 (define-move-fun (load-immediate 1) (vop x y)
  28   ((null immediate)
  29    (any-reg descriptor-reg))
  30   (let ((val (tn-value x)))
  31     (etypecase val
  32       (integer
  33        ;; This is a FIXNUM, as IMMEDIATE-CONSTANT-SC only
  34        ;; accepts integers if they are FIXNUMs.
  35        (load-immediate-word y (fixnumize val)))
  36       (character
  37        (let* ((codepoint (char-code val))
  38               (encoded-character (dpb codepoint (byte 24 8) character-widetag)))
  39          (load-immediate-word y encoded-character)))
  40       (null
  41        (move y null-tn))
  42       (symbol
  43        (load-symbol y val)))))
  44
  45 (define-move-fun (load-number 1) (vop x y)
  46   ((immediate)
  47    (signed-reg unsigned-reg))
  48   (load-immediate-word y (tn-value x)))
  49
  50 (define-move-fun (load-character 1) (vop x y)
  51   ((immediate) (character-reg))
  52   (inst mov y (char-code (tn-value x))))
  53
  54 (define-move-fun (load-system-area-pointer 1) (vop x y)
  55   ((immediate) (sap-reg))
  56   (let ((immediate-label (gen-label)))
  57     (assemble (*elsewhere*)
  58       (emit-label immediate-label)
  59       (inst word (sap-int (tn-value x))))
  60     (inst ldr y (@ immediate-label))))
  61
  62 (define-move-fun (load-constant 5) (vop x y)
  63   ((constant) (descriptor-reg))
  64   (loadw y code-tn (tn-offset x) other-pointer-lowtag))
  65
  66 (define-move-fun (load-stack 5) (vop x y)
  67   ((control-stack) (any-reg descriptor-reg))
  68   (load-stack-tn y x))
  69
  70 (define-move-fun (load-number-stack 5) (vop x y)
  71   ((character-stack) (character-reg)
  72    (sap-stack) (sap-reg)
  73    (signed-stack) (signed-reg)
  74    (unsigned-stack) (unsigned-reg))
  75   (let ((nfp (current-nfp-tn vop)))
  76     (loadw y nfp (tn-offset x))))
  77
  78 (define-move-fun (store-stack 5) (vop x y)
  79   ((any-reg descriptor-reg) (control-stack))
  80   (store-stack-tn y x))
  81
  82 (define-move-fun (store-number-stack 5) (vop x y)
  83   ((character-reg) (character-stack)
  84    (sap-reg) (sap-stack)
  85    (signed-reg) (signed-stack)
  86    (unsigned-reg) (unsigned-stack))
  87   (let ((nfp (current-nfp-tn vop)))
  88     (storew x nfp (tn-offset y))))
  89
  90 \f
  91 ;;;; The Move VOP:
  92 (define-vop (move)
  93   (:args (x :target y
  94             :scs (any-reg descriptor-reg null)
  95             :load-if (not (location= x y))))
  96   (:results (y :scs (any-reg descriptor-reg)
  97                :load-if (not (location= x y))))
  98   (:effects)
  99   (:affected)
 100   (:generator 0
 101     (move y x)))
 102
 103 (define-move-vop move :move
 104   (any-reg descriptor-reg)
 105   (any-reg descriptor-reg))
 106
 107 ;;; Make MOVE the check VOP for T so that type check generation
 108 ;;; doesn't think it is a hairy type.  This also allows checking of a
 109 ;;; few of the values in a continuation to fall out.
 110 (primitive-type-vop move (:check) t)
 111
 112 ;;; The MOVE-ARG VOP is used for moving descriptor values into another
 113 ;;; frame for argument or known value passing.
 114 (define-vop (move-arg)
 115   (:args (x :target y
 116             :scs (any-reg descriptor-reg null))
 117          (fp :scs (any-reg)
 118              :load-if (not (sc-is y any-reg descriptor-reg))))
 119   (:results (y))
 120   (:generator 0
 121     (sc-case y
 122       ((any-reg descriptor-reg)
 123        (move y x))
 124       (control-stack
 125        (storew x fp (tn-offset y))))))
 126 ;;;
 127 (define-move-vop move-arg :move-arg
 128   (any-reg descriptor-reg)
 129   (any-reg descriptor-reg))
 130
 131
 132 \f
 133 ;;;; ILLEGAL-MOVE
 134
 135 ;;; This VOP exists just to begin the lifetime of a TN that couldn't
 136 ;;; be written legally due to a type error.  An error is signalled
 137 ;;; before this VOP is so we don't need to do anything (not that there
 138 ;;; would be anything sensible to do anyway.)
 139 (define-vop (illegal-move)
 140   (:args (x) (type))
 141   (:results (y))
 142   (:ignore y)
 143   (:vop-var vop)
 144   (:save-p :compute-only)
 145   (:generator 666
 146     (error-call vop 'object-not-type-error x type)))
 147 \f
 148 ;;;; Moves and coercions:
 149
 150 ;;; These MOVE-TO-WORD VOPs move a tagged integer to a raw full-word
 151 ;;; representation.  Similarly, the MOVE-FROM-WORD VOPs converts a raw integer
 152 ;;; to a tagged bignum or fixnum.
 153
 154 ;;; ARG is a fixnum, so just shift it.  We need a type restriction because some
 155 ;;; possible arg SCs (control-stack) overlap with possible bignum arg SCs.
 156 (define-vop (move-to-word/fixnum)
 157   (:args (x :scs (any-reg descriptor-reg)))
 158   (:results (y :scs (signed-reg unsigned-reg)))
 159   (:arg-types tagged-num)
 160   (:note "fixnum untagging")
 161   (:generator 1
 162     (inst mov y (asr x n-fixnum-tag-bits))))
 163 (define-move-vop move-to-word/fixnum :move
 164   (any-reg descriptor-reg) (signed-reg unsigned-reg))
 165
 166 ;;; ARG is a non-immediate constant; load it.
 167 (define-vop (move-to-word-c)
 168   (:args (x :scs (constant)))
 169   (:results (y :scs (signed-reg unsigned-reg)))
 170   (:note "constant load")
 171   (:generator 1
 172     (cond ((sb!c::tn-leaf x)
 173            (load-immediate-word y (tn-value x)))
 174           (t
 175            (loadw y code-tn (tn-offset x) other-pointer-lowtag)
 176            (inst mov y (asr y n-fixnum-tag-bits))))))
 177 (define-move-vop move-to-word-c :move
 178   (constant) (signed-reg unsigned-reg))
 179
 180 ;;; ARG is a fixnum or bignum; figure out which and load if necessary.
 181 (define-vop (move-to-word/integer)
 182   (:args (x :scs (descriptor-reg)))
 183   (:results (y :scs (signed-reg unsigned-reg)))
 184   (:note "integer to untagged word coercion")
 185   (:generator 4
 186     (inst tst x fixnum-tag-mask)
 187     (sc-case y
 188       (signed-reg
 189        (inst mov :eq y (asr x n-fixnum-tag-bits)))
 190       (unsigned-reg
 191        (inst mov :eq y (lsr x n-fixnum-tag-bits))))
 192     (loadw y x bignum-digits-offset other-pointer-lowtag :ne)))
 193
 194 (define-move-vop move-to-word/integer :move
 195   (descriptor-reg) (signed-reg unsigned-reg))
 196
 197 ;;; RESULT is a fixnum, so we can just shift.  We need the result type
 198 ;;; restriction because of the control-stack ambiguity noted above.
 199 (define-vop (move-from-word/fixnum)
 200   (:args (x :scs (signed-reg unsigned-reg)))
 201   (:results (y :scs (any-reg descriptor-reg)))
 202   (:result-types tagged-num)
 203   (:note "fixnum tagging")
 204   (:generator 1
 205     (inst mov y (lsl x n-fixnum-tag-bits))))
 206 (define-move-vop move-from-word/fixnum :move
 207   (signed-reg unsigned-reg) (any-reg descriptor-reg))
 208
 209
 210 ;;; RESULT may be a bignum, so we have to check.  Use a worst-case
 211 ;;; cost to make sure people know they may be number consing.
 212 (define-vop (move-from-signed)
 213   (:args (arg :scs (signed-reg unsigned-reg) :target x))
 214   (:results (y :scs (any-reg descriptor-reg)))
 215   (:temporary (:scs (non-descriptor-reg) :from (:argument 0)) x)
 216   (:temporary (:sc non-descriptor-reg :offset ocfp-offset) pa-flag)
 217   (:note "signed word to integer coercion")
 218   (:generator 20
 219     (move x arg)
 220     (inst adds pa-flag x x)
 221     (inst adds :vc y pa-flag pa-flag)
 222     (inst b :vc DONE)
 223
 224     (with-fixed-allocation (y pa-flag bignum-widetag (1+ bignum-digits-offset))
 225       (storew x y bignum-digits-offset other-pointer-lowtag))
 226     DONE))
 227 (define-move-vop move-from-signed :move
 228   (signed-reg) (descriptor-reg))
 229
 230 ;;; Check for fixnum, and possibly allocate one or two word bignum
 231 ;;; result.  Use a worst-case cost to make sure people know they may
 232 ;;; be number consing.
 233 (define-vop (move-from-unsigned)
 234   (:args (arg :scs (signed-reg unsigned-reg) :target x))
 235   (:results (y :scs (any-reg descriptor-reg)))
 236   (:temporary (:scs (non-descriptor-reg) :from (:argument 0)) x)
 237   (:temporary (:sc non-descriptor-reg :offset ocfp-offset) pa-flag)
 238   (:note "unsigned word to integer coercion")
 239   (:generator 20
 240     (move x arg)
 241     (inst tst x (ash (1- (ash 1 (- n-word-bits
 242                                    n-positive-fixnum-bits)))
 243                      n-positive-fixnum-bits))
 244     (inst mov y (lsl x n-fixnum-tag-bits))
 245     (inst b :eq DONE)
 246
 247     (with-fixed-allocation
 248         (y pa-flag bignum-widetag (+ 2 bignum-digits-offset))
 249       ;; WITH-FIXED-ALLOCATION, when using a supplied type-code,
 250       ;; leaves PA-FLAG containing the computed header value.  In our
 251       ;; case, configured for a 2-word bignum.  If the sign bit in the
 252       ;; value we're boxing is CLEAR, we need to shrink the bignum by
 253       ;; one word, hence the following:
 254       (inst orrs x x 0)
 255       (inst sub :pl pa-flag pa-flag #x100)
 256       (storew pa-flag y 0 other-pointer-lowtag :pl)
 257       (storew x y bignum-digits-offset other-pointer-lowtag))
 258     DONE))
 259 (define-move-vop move-from-unsigned :move
 260   (unsigned-reg) (descriptor-reg))
 261
 262
 263 ;;; Move untagged numbers.
 264 (define-vop (word-move)
 265   (:args (x :target y
 266             :scs (signed-reg unsigned-reg)
 267             :load-if (not (location= x y))))
 268   (:results (y :scs (signed-reg unsigned-reg)
 269                :load-if (not (location= x y))))
 270   (:effects)
 271   (:affected)
 272   (:note "word integer move")
 273   (:generator 0
 274     (move y x)))
 275 (define-move-vop word-move :move
 276   (signed-reg unsigned-reg) (signed-reg unsigned-reg))
 277
 278
 279 ;;; Move untagged number arguments/return-values.
 280 (define-vop (move-word-arg)
 281   (:args (x :target y
 282             :scs (signed-reg unsigned-reg))
 283          (fp :scs (any-reg)
 284              :load-if (not (sc-is y sap-reg))))
 285   (:results (y))
 286   (:note "word integer argument move")
 287   (:generator 0
 288     (sc-case y
 289       ((signed-reg unsigned-reg)
 290        (move y x))
 291       ((signed-stack unsigned-stack)
 292        (storew x fp (tn-offset y))))))
 293 (define-move-vop move-word-arg :move-arg
 294   (descriptor-reg any-reg signed-reg unsigned-reg) (signed-reg unsigned-reg))
 295
 296 ;;; Use standard MOVE-ARG + coercion to move an untagged number to a
 297 ;;; descriptor passing location.
 298 (define-move-vop move-arg :move-arg
 299   (signed-reg unsigned-reg) (any-reg descriptor-reg))