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;;;; functions to implement bitblt-ish operations
;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; This software is derived from the CMU CL system, which was
;;;; written at Carnegie Mellon University and released into the
;;;; public domain. The software is in the public domain and is
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.
(in-package "SB!VM")
;;;; types
(eval-when (:compile-toplevel :load-toplevel :execute)
(deftype bit-offset () '(integer 0 (#.sb!vm:n-word-bits))))
;;;; support routines
;;; A particular implementation must offer either VOPs to translate
;;; these, or DEFTRANSFORMs to convert them into something supported
;;; by the architecture.
(macrolet ((def (name &rest args)
`(defun ,name ,args
(,name ,@args))))
(def word-logical-not x)
(def word-logical-and x y)
(def word-logical-or x y)
(def word-logical-xor x y)
(def word-logical-nor x y)
(def word-logical-eqv x y)
(def word-logical-nand x y)
(def word-logical-andc1 x y)
(def word-logical-andc2 x y)
(def word-logical-orc1 x y)
(def word-logical-orc2 x y))
;;; Shift NUMBER by the low-order bits of COUNTOID, adding zero bits
;;; at the "end" and removing bits from the "start". On big-endian
;;; machines this is a left-shift and on little-endian machines this
;;; is a right-shift.
(eval-when (:compile-toplevel :load-toplevel :execute)
(defun shift-towards-start (number countoid)
(declare (type sb!vm:word number) (fixnum countoid))
(let ((count (ldb (byte (1- (integer-length sb!vm:n-word-bits)) 0) countoid)))
(declare (type bit-offset count))
(if (zerop count)
number
(ecase sb!c:*backend-byte-order*
(:big-endian
(ash (ldb (byte (- sb!vm:n-word-bits count) 0) number) count))
(:little-endian
(ash number (- count))))))))
;;; Shift NUMBER by COUNT bits, adding zero bits at the "start" and
;;; removing bits from the "end". On big-endian machines this is a
;;; right-shift and on little-endian machines this is a left-shift.
(eval-when (:compile-toplevel :load-toplevel :execute)
(defun shift-towards-end (number count)
(declare (type sb!vm:word number) (fixnum count))
(let ((count (ldb (byte (1- (integer-length sb!vm:n-word-bits)) 0) count)))
(declare (type bit-offset count))
(if (zerop count)
number
(ecase sb!c:*backend-byte-order*
(:big-endian
(ash number (- count)))
(:little-endian
(ash (ldb (byte (- sb!vm:n-word-bits count) 0) number) count)))))))
#!-sb-fluid (declaim (inline start-mask end-mask))
;;; Produce a mask that contains 1's for the COUNT "start" bits and
;;; 0's for the remaining "end" bits. Only the lower 5 bits of COUNT
;;; are significant (KLUDGE: because of hardwired implicit dependence
;;; on 32-bit word size -- WHN 2001-03-19).
(defun start-mask (count)
(declare (fixnum count))
(shift-towards-start (1- (ash 1 sb!vm:n-word-bits)) (- count)))
;;; Produce a mask that contains 1's for the COUNT "end" bits and 0's
;;; for the remaining "start" bits. Only the lower 5 bits of COUNT are
;;; significant (KLUDGE: because of hardwired implicit dependence on
;;; 32-bit word size -- WHN 2001-03-19).
(defun end-mask (count)
(declare (fixnum count))
(shift-towards-end (1- (ash 1 sb!vm:n-word-bits)) (- count)))
#!-sb-fluid (declaim (inline word-sap-ref %set-word-sap-ref))
(defun word-sap-ref (sap offset)
(declare (type system-area-pointer sap)
(type index offset)
(values sb!vm:word)
(optimize (speed 3) (safety 0) #-sb-xc-host (inhibit-warnings 3)))
(sap-ref-word sap (the index (ash offset sb!vm:word-shift))))
(defun %set-word-sap-ref (sap offset value)
(declare (type system-area-pointer sap)
(type index offset)
(type sb!vm:word value)
(values sb!vm:word)
(optimize (speed 3) (safety 0) (inhibit-warnings 3)))
(setf (sap-ref-word sap (the index (ash offset sb!vm:word-shift)))
value))
;;; the actual bashers and common uses of same
;;; This is a little ugly. Fixing bug 188 would bring the ability to
;;; wrap a MACROLET or something similar around this whole thing would
;;; make things significantly less ugly. --njf, 2005-02-23
(eval-when (:compile-toplevel :load-toplevel :execute)
;;; Align the SAP to a word boundary, and update the offset accordingly.
(defmacro !define-sap-fixer (bitsize)
(let ((name (intern (format nil "FIX-SAP-AND-OFFSET-UB~D" bitsize))))
`(progn
(declaim (inline ,name))
(defun ,name (sap offset)
(declare (type system-area-pointer sap)
(type index offset)
(values system-area-pointer index))
(let ((address (sap-int sap))
(word-mask (1- (ash 1 word-shift))))
(values (int-sap #!-alpha (word-logical-andc2 address word-mask)
;; KLUDGE: WORD-LOGICAL-ANDC2 is defined in
;; terms of n-word-bits. On all systems
;; where n-word-bits is not equal to
;; n-machine-word-bits we have to do this
;; another way. At this time, these
;; systems are alphas, though there was
;; some talk about an x86-64 build option.
#!+alpha (ash (ash address (- word-shift)) word-shift))
(+ ,(ecase bitsize
((1 2 4) `(* (logand address word-mask)
(/ n-byte-bits ,bitsize)))
((8 16 32 64) '(logand address word-mask)))
offset)))))))
;;; We cheat a little bit by using TRULY-THE in the copying function to
;;; force the compiler to generate good code in the (= BITSIZE
;;; SB!VM:N-WORD-BITS) case. We don't use TRULY-THE in the other cases
;;; to give the compiler freedom to generate better code.
(defmacro !define-byte-bashers (bitsize)
(let* ((bytes-per-word (/ n-word-bits bitsize))
(byte-offset `(integer 0 (,bytes-per-word)))
(byte-count `(integer 1 (,bytes-per-word)))
(max-bytes (ash sb!xc:most-positive-fixnum
;; FIXME: this reflects code contained in the
;; original bit-bash.lisp, but seems very
;; nonsensical. Why shouldn't we be able to
;; handle M-P-FIXNUM bits? And if we can't,
;; are these other shift amounts bogus, too?
(ecase bitsize
(1 -2)
(2 -1)
(4 0)
(8 0)
(16 0)
(32 0)
(64 0))))
(offset `(integer 0 ,max-bytes))
(max-word-offset (ceiling max-bytes bytes-per-word))
(word-offset `(integer 0 ,max-word-offset))
(fix-sap-and-offset-name (intern (format nil "FIX-SAP-AND-OFFSET-UB~D" bitsize)))
(constant-bash-name (intern (format nil "CONSTANT-UB~D-BASH" bitsize) (find-package "SB!KERNEL")))
(array-fill-name (intern (format nil "UB~D-BASH-FILL" bitsize) (find-package "SB!KERNEL")))
(system-area-fill-name (intern (format nil "SYSTEM-AREA-UB~D-FILL" bitsize) (find-package "SB!KERNEL")))
(unary-bash-name (intern (format nil "UNARY-UB~D-BASH" bitsize) (find-package "SB!KERNEL")))
(array-copy-name (intern (format nil "UB~D-BASH-COPY" bitsize) (find-package "SB!KERNEL")))
(system-area-copy-name (intern (format nil "SYSTEM-AREA-UB~D-COPY" bitsize) (find-package "SB!KERNEL")))
(array-copy-to-system-area-name
(intern (format nil "COPY-UB~D-TO-SYSTEM-AREA" bitsize) (find-package "SB!KERNEL")))
(system-area-copy-to-array-name
(intern (format nil "COPY-UB~D-FROM-SYSTEM-AREA" bitsize)
(find-package "SB!KERNEL"))))
`(progn
(declaim (inline ,constant-bash-name ,unary-bash-name))
;; Fill DST with VALUE starting at DST-OFFSET and continuing
;; for LENGTH bytes (however bytes are defined).
(defun ,constant-bash-name (dst dst-offset length value
dst-ref-fn dst-set-fn)
(declare (type word value) (type index dst-offset length))
(declare (ignorable dst-ref-fn))
(multiple-value-bind (dst-word-offset dst-byte-offset)
(floor dst-offset ,bytes-per-word)
(declare (type ,word-offset dst-word-offset)
(type ,byte-offset dst-byte-offset))
(multiple-value-bind (n-words final-bytes)
(floor (+ dst-byte-offset length) ,bytes-per-word)
(declare (type ,word-offset n-words)
(type ,byte-offset final-bytes))
(if (zerop n-words)
,(unless (= bytes-per-word 1)
`(unless (zerop length)
(locally (declare (type ,byte-count length))
(funcall dst-set-fn dst dst-word-offset
(if (= length ,bytes-per-word)
value
(let ((mask (shift-towards-end
(start-mask (* length ,bitsize))
(* dst-byte-offset ,bitsize))))
(word-logical-or (word-logical-and value mask)
(word-logical-andc2 (funcall dst-ref-fn dst dst-word-offset)
mask))))))))
(let ((interior (floor (- length final-bytes) ,bytes-per-word)))
,@(unless (= bytes-per-word 1)
`((unless (zerop dst-byte-offset)
(let ((mask (end-mask (* (- dst-byte-offset) ,bitsize))))
(funcall dst-set-fn dst dst-word-offset
(word-logical-or (word-logical-and value mask)
(word-logical-andc2 (funcall dst-ref-fn dst dst-word-offset)
mask))))
(incf dst-word-offset))))
(let ((end (+ dst-word-offset interior)))
(declare (type ,word-offset end))
(do ()
((>= dst-word-offset end))
(funcall dst-set-fn dst dst-word-offset value)
(incf dst-word-offset)))
#+nil
(dotimes (i interior)
(funcall dst-set-fn dst dst-word-offset value)
(incf dst-word-offset))
,@(unless (= bytes-per-word 1)
`((unless (zerop final-bytes)
(let ((mask (start-mask (* final-bytes ,bitsize))))
(funcall dst-set-fn dst dst-word-offset
(word-logical-or (word-logical-and value mask)
(word-logical-andc2 (funcall dst-ref-fn dst dst-word-offset)
mask)))))))))))
(values))
;; common uses for constant-byte-bashing
(defknown ,array-fill-name (word simple-unboxed-array ,offset ,offset)
simple-unboxed-array
()
:result-arg 1)
(defun ,array-fill-name (value dst dst-offset length)
(declare (type word value) (type ,offset dst-offset length))
(declare (optimize (speed 3) (safety 1)))
(,constant-bash-name dst dst-offset length value
#'%vector-raw-bits #'%set-vector-raw-bits)
dst)
(defun ,system-area-fill-name (value dst dst-offset length)
(declare (type word value) (type ,offset dst-offset length))
(declare (optimize (speed 3) (safety 1)))
(multiple-value-bind (dst dst-offset) (,fix-sap-and-offset-name dst dst-offset)
(,constant-bash-name dst dst-offset length value
#'word-sap-ref #'%set-word-sap-ref)))
;; unary byte bashing (copying)
(defun ,unary-bash-name (src src-offset dst dst-offset length
dst-ref-fn dst-set-fn src-ref-fn)
(declare (type index src-offset dst-offset length)
(type function dst-ref-fn dst-set-fn src-ref-fn)
(ignorable dst-ref-fn))
(multiple-value-bind (dst-word-offset dst-byte-offset)
(floor dst-offset ,bytes-per-word)
(declare (type ,word-offset dst-word-offset)
(type ,byte-offset dst-byte-offset))
(multiple-value-bind (src-word-offset src-byte-offset)
(floor src-offset ,bytes-per-word)
(declare (type ,word-offset src-word-offset)
(type ,byte-offset src-byte-offset))
(cond
((<= (+ dst-byte-offset length) ,bytes-per-word)
;; We are only writing one word, so it doesn't matter what
;; order we do it in. But we might be reading from
;; multiple words, so take care.
(cond
((zerop length)
;; We're not writing anything. This is really easy.
)
((= length ,bytes-per-word)
;; DST-BYTE-OFFSET must be equal to zero, or we would be
;; writing multiple words. If SRC-BYTE-OFFSET is also zero,
;; the we just transfer the single word. Otherwise we have
;; to extract bytes from two source words.
(funcall dst-set-fn dst dst-word-offset
(cond
((zerop src-byte-offset)
(funcall src-ref-fn src src-word-offset))
,@(unless (= bytes-per-word 1)
`((t (word-logical-or (shift-towards-start
(funcall src-ref-fn src src-word-offset)
(* src-byte-offset ,bitsize))
(shift-towards-end
(funcall src-ref-fn src (1+ src-word-offset))
(* (- src-byte-offset) ,bitsize)))))))))
,@(unless (= bytes-per-word 1)
`((t
;; We are only writing some portion of the destination word.
;; We still don't know whether we need one or two source words.
(locally (declare (type ,byte-count length))
(let ((mask (shift-towards-end (start-mask (* length ,bitsize))
(* dst-byte-offset ,bitsize)))
(orig (funcall dst-ref-fn dst dst-word-offset))
(value (if (> src-byte-offset dst-byte-offset)
;; The source starts further
;; into the word than does the
;; destination, so the source
;; could extend into the next
;; word. If it does, we have
;; to merge the two words, and
;; it not, we can just shift
;; the first word.
(let ((src-byte-shift (- src-byte-offset
dst-byte-offset)))
(if (> (+ src-byte-offset length) ,bytes-per-word)
(word-logical-or
(shift-towards-start
(funcall src-ref-fn src src-word-offset)
(* src-byte-shift ,bitsize))
(shift-towards-end
(funcall src-ref-fn src (1+ src-word-offset))
(* (- src-byte-shift) ,bitsize)))
(shift-towards-start (funcall src-ref-fn src src-word-offset)
(* src-byte-shift ,bitsize))))
;; The destination starts further
;; into the word than does the
;; source, so we know the source
;; cannot extend into a second
;; word (or else the destination
;; would too, and we wouldn't be
;; in this branch).
(shift-towards-end
(funcall src-ref-fn src src-word-offset)
(* (- dst-byte-offset src-byte-offset) ,bitsize)))))
(declare (type word mask orig value))
(funcall dst-set-fn dst dst-word-offset
(word-logical-or (word-logical-and value mask)
(word-logical-andc2 orig mask))))))))))
((= src-byte-offset dst-byte-offset)
;; The source and destination are aligned, so shifting
;; is unnecessary. But we have to pick the direction
;; of the copy in case the source and destination are
;; really the same object.
(multiple-value-bind (words final-bytes)
(floor (+ dst-byte-offset length) ,bytes-per-word)
(declare (type ,word-offset words)
(type ,byte-offset final-bytes))
(let ((interior (floor (- length final-bytes) ,bytes-per-word)))
(declare (type ,word-offset interior))
(cond
((<= dst-offset src-offset)
;; We need to loop from left to right.
,@(unless (= bytes-per-word 1)
`((unless (zerop dst-byte-offset)
;; We are only writing part of the first word, so mask
;; off the bytes we want to preserve.
(let ((mask (end-mask (* (- dst-byte-offset) ,bitsize)))
(orig (funcall dst-ref-fn dst dst-word-offset))
(value (funcall src-ref-fn src src-word-offset)))
(declare (type word mask orig value))
(funcall dst-set-fn dst dst-word-offset
(word-logical-or (word-logical-and value mask)
(word-logical-andc2 orig mask))))
(incf src-word-offset)
(incf dst-word-offset))))
;; Copy the interior words.
(let ((end ,(if (= bytes-per-word 1)
`(truly-the ,word-offset
(+ dst-word-offset interior))
`(+ dst-word-offset interior))))
(declare (type ,word-offset end))
(do ()
((>= dst-word-offset end))
(funcall dst-set-fn dst dst-word-offset
(funcall src-ref-fn src src-word-offset))
,(if (= bytes-per-word 1)
`(setf src-word-offset (truly-the ,word-offset (+ src-word-offset 1)))
`(incf src-word-offset))
(incf dst-word-offset)))
,@(unless (= bytes-per-word 1)
`((unless (zerop final-bytes)
;; We are only writing part of the last word.
(let ((mask (start-mask (* final-bytes ,bitsize)))
(orig (funcall dst-ref-fn dst dst-word-offset))
(value (funcall src-ref-fn src src-word-offset)))
(declare (type word mask orig value))
(funcall dst-set-fn dst dst-word-offset
(word-logical-or (word-logical-and value mask)
(word-logical-andc2 orig mask))))))))
(t
;; We need to loop from right to left.
,(if (= bytes-per-word 1)
`(setf dst-word-offset (truly-the ,word-offset
(+ dst-word-offset words)))
`(incf dst-word-offset words))
,(if (= bytes-per-word 1)
`(setf src-word-offset (truly-the ,word-offset
(+ src-word-offset words)))
`(incf src-word-offset words))
,@(unless (= bytes-per-word 1)
`((unless (zerop final-bytes)
(let ((mask (start-mask (* final-bytes ,bitsize)))
(orig (funcall dst-ref-fn dst dst-word-offset))
(value (funcall src-ref-fn src src-word-offset)))
(declare (type word mask orig value))
(funcall dst-set-fn dst dst-word-offset
(word-logical-or (word-logical-and value mask)
(word-logical-andc2 orig mask)))))))
(let ((end (- dst-word-offset interior)))
(do ()
((<= dst-word-offset end))
(decf src-word-offset)
(decf dst-word-offset)
(funcall dst-set-fn dst dst-word-offset
(funcall src-ref-fn src src-word-offset))))
,@(unless (= bytes-per-word 1)
`((unless (zerop dst-byte-offset)
;; We are only writing part of the last word.
(decf src-word-offset)
(decf dst-word-offset)
(let ((mask (end-mask (* (- dst-byte-offset) ,bitsize)))
(orig (funcall dst-ref-fn dst dst-word-offset))
(value (funcall src-ref-fn src src-word-offset)))
(declare (type word mask orig value))
(funcall dst-set-fn dst dst-word-offset
(word-logical-or (word-logical-and value mask)
(word-logical-andc2 orig mask))))))))))))
(t
;; Source and destination are not aligned.
(multiple-value-bind (words final-bytes)
(floor (+ dst-byte-offset length) ,bytes-per-word)
(declare (type ,word-offset words)
(type ,byte-offset final-bytes))
(let ((src-shift (mod (- src-byte-offset dst-byte-offset)
,bytes-per-word))
(interior (floor (- length final-bytes) ,bytes-per-word)))
(declare (type ,word-offset interior)
(type ,byte-offset src-shift))
(cond
((<= dst-offset src-offset)
;; We need to loop from left to right.
(let ((prev 0)
(next (funcall src-ref-fn src src-word-offset)))
(declare (type word prev next))
(flet ((get-next-src ()
(setf prev next)
(setf next (funcall src-ref-fn src
(incf src-word-offset)))))
(declare (inline get-next-src))
,@(unless (= bytes-per-word 1)
`((unless (zerop dst-byte-offset)
(when (> src-byte-offset dst-byte-offset)
(get-next-src))
(let ((mask (end-mask (* (- dst-byte-offset) ,bitsize)))
(orig (funcall dst-ref-fn dst dst-word-offset))
(value (word-logical-or (shift-towards-start prev (* src-shift ,bitsize))
(shift-towards-end next (* (- src-shift) ,bitsize)))))
(declare (type word mask orig value))
(funcall dst-set-fn dst dst-word-offset
(word-logical-or (word-logical-and value mask)
(word-logical-andc2 orig mask))))
(incf dst-word-offset))))
(let ((end (+ dst-word-offset interior)))
(declare (type ,word-offset end))
(do ()
((>= dst-word-offset end))
(get-next-src)
(let ((value (word-logical-or
(shift-towards-end next (* (- src-shift) ,bitsize))
(shift-towards-start prev (* src-shift ,bitsize)))))
(declare (type word value))
(funcall dst-set-fn dst dst-word-offset value)
(incf dst-word-offset))))
,@(unless (= bytes-per-word 1)
`((unless (zerop final-bytes)
(let ((value
(if (> (+ final-bytes src-shift) ,bytes-per-word)
(progn
(get-next-src)
(word-logical-or
(shift-towards-end next (* (- src-shift) ,bitsize))
(shift-towards-start prev (* src-shift ,bitsize))))
(shift-towards-start next (* src-shift ,bitsize))))
(mask (start-mask (* final-bytes ,bitsize)))
(orig (funcall dst-ref-fn dst dst-word-offset)))
(declare (type word mask orig value))
(funcall dst-set-fn dst dst-word-offset
(word-logical-or (word-logical-and value mask)
(word-logical-andc2 orig mask))))))))))
(t
;; We need to loop from right to left.
(incf dst-word-offset words)
(incf src-word-offset (1- (ceiling (+ src-byte-offset length) ,bytes-per-word)))
(let ((next 0)
(prev (funcall src-ref-fn src src-word-offset)))
(declare (type word prev next))
(flet ((get-next-src ()
(setf next prev)
(setf prev (funcall src-ref-fn src (decf src-word-offset)))))
(declare (inline get-next-src))
,@(unless (= bytes-per-word 1)
`((unless (zerop final-bytes)
(when (> final-bytes (- ,bytes-per-word src-shift))
(get-next-src))
(let ((value (word-logical-or
(shift-towards-end next (* (- src-shift) ,bitsize))
(shift-towards-start prev (* src-shift ,bitsize))))
(mask (start-mask (* final-bytes ,bitsize)))
(orig (funcall dst-ref-fn dst dst-word-offset)))
(declare (type word mask orig value))
(funcall dst-set-fn dst dst-word-offset
(word-logical-or (word-logical-and value mask)
(word-logical-andc2 orig mask)))))))
(decf dst-word-offset)
(let ((end (- dst-word-offset interior)))
(do ()
((<= dst-word-offset end))
(get-next-src)
(let ((value (word-logical-or
(shift-towards-end next (* (- src-shift) ,bitsize))
(shift-towards-start prev (* src-shift ,bitsize)))))
(declare (type word value))
(funcall dst-set-fn dst dst-word-offset value)
(decf dst-word-offset))))
,@(unless (= bytes-per-word 1)
`((unless (zerop dst-byte-offset)
(if (> src-byte-offset dst-byte-offset)
(get-next-src)
(setf next prev prev 0))
(let ((mask (end-mask (* (- dst-byte-offset) ,bitsize)))
(orig (funcall dst-ref-fn dst dst-word-offset))
(value (word-logical-or
(shift-towards-start prev (* src-shift ,bitsize))
(shift-towards-end next (* (- src-shift) ,bitsize)))))
(declare (type word mask orig value))
(funcall dst-set-fn dst dst-word-offset
(word-logical-or (word-logical-and value mask)
(word-logical-andc2 orig mask)))))))))))))))))
(values))
;; common uses for unary-byte-bashing
(defun ,array-copy-name (src src-offset dst dst-offset length)
(declare (type ,offset src-offset dst-offset length))
(locally (declare (optimize (speed 3) (safety 1)))
(,unary-bash-name src src-offset dst dst-offset length
#'%vector-raw-bits
#'%set-vector-raw-bits
#'%vector-raw-bits)))
(defun ,system-area-copy-name (src src-offset dst dst-offset length)
(declare (type ,offset src-offset dst-offset length))
(locally (declare (optimize (speed 3) (safety 1)))
(multiple-value-bind (src src-offset) (,fix-sap-and-offset-name src src-offset)
(declare (type sb!sys:system-area-pointer src))
(multiple-value-bind (dst dst-offset) (,fix-sap-and-offset-name dst dst-offset)
(declare (type sb!sys:system-area-pointer dst))
(,unary-bash-name src src-offset dst dst-offset length
#'word-sap-ref #'%set-word-sap-ref
#'word-sap-ref)))))
(defun ,array-copy-to-system-area-name (src src-offset dst dst-offset length)
(declare (type ,offset src-offset dst-offset length))
(locally (declare (optimize (speed 3) (safety 1)))
(multiple-value-bind (dst dst-offset) (,fix-sap-and-offset-name dst dst-offset)
(,unary-bash-name src src-offset dst dst-offset length
#'word-sap-ref #'%set-word-sap-ref
#'%vector-raw-bits))))
(defun ,system-area-copy-to-array-name (src src-offset dst dst-offset length)
(declare (type ,offset src-offset dst-offset length))
(locally (declare (optimize (speed 3) (safety 1)))
(multiple-value-bind (src src-offset) (,fix-sap-and-offset-name src src-offset)
(,unary-bash-name src src-offset dst dst-offset length
#'%vector-raw-bits
#'%set-vector-raw-bits
#'word-sap-ref)))))))
) ; EVAL-WHEN
;;; We would normally do this with a MACROLET, but then we run into
;;; problems with the lexical environment being too hairy for the
;;; cross-compiler and it cannot inline the basic basher functions.
#.(loop for i = 1 then (* i 2)
collect `(!define-sap-fixer ,i) into fixers
collect `(!define-byte-bashers ,i) into bashers
until (= i sb!vm:n-word-bits)
;; FIXERS must come first so their inline expansions are available
;; for the bashers.
finally (return `(progn ,@fixers ,@bashers)))
;;; a common idiom for calling COPY-TO-SYSTEM-AREA
;;;
;;; Copy the entire contents of the vector V to memory starting at SAP+OFFSET.
(defun copy-byte-vector-to-system-area (bv sap &optional (offset 0))
;; FIXME: There should be a type like SB!VM:BYTE so that we can write this
;; type as (SIMPLE-ARRAY SB!VM:BYTE 1). Except BYTE is an external symbol of
;; package CL, and shadowing it would be too ugly; so maybe SB!VM:VMBYTE?
;; (And then N-BYTE-BITS would be N-VMBYTE-BITS and so forth?)
(declare (type (simple-array (unsigned-byte 8) 1) bv))
(declare (type system-area-pointer sap))
(declare (type fixnum offset))
(copy-ub8-to-system-area bv 0 sap offset (length bv)))
;;;; Bashing-Style search for bits
;;;;
;;;; Similar search would work well for base-strings as well.
;;;; (Technically for all unboxed sequences of sub-word size elements,
;;;; but somehow I doubt other eg. octet vectors get POSIION or FIND
;;;; used as much on them.)
(defconstant +bit-position-base-mask+ (1- n-word-bits))
(defconstant +bit-position-base-shift+ (integer-length +bit-position-base-mask+))
(macrolet ((def (name frob)
`(defun ,name (vector from-end start end)
(declare (simple-bit-vector vector)
(index start end)
(optimize (speed 3) (safety 0)))
(unless (= start end)
(let* ((last-word (ash end (- +bit-position-base-shift+)))
(last-bits (logand end +bit-position-base-mask+))
(first-word (ash start (- +bit-position-base-shift+)))
(first-bits (logand start +bit-position-base-mask+))
;; These mask out everything but the interesting parts.
(end-mask #!+little-endian (lognot (ash -1 last-bits))
#!+big-endian (ash -1 (- sb!vm:n-word-bits last-bits)))
(start-mask #!+little-endian (ash -1 first-bits)
#!+big-endian (lognot (ash -1 (- sb!vm:n-word-bits first-bits)))))
(declare (index last-word first-word))
(flet ((#!+little-endian start-bit
#!+big-endian end-bit (x)
(declare (word x))
(- #!+big-endian sb!vm:n-word-bits
(integer-length (logand x (- x)))
#!+little-endian 1))
(#!+little-endian end-bit
#!+big-endian start-bit (x)
(declare (word x))
(- #!+big-endian sb!vm:n-word-bits
(integer-length x)
#!+little-endian 1))
(found (i word-offset)
(declare (index i word-offset))
(return-from ,name
(logior i (truly-the
fixnum
(ash word-offset +bit-position-base-shift+)))))
(get-word (sap offset)
(,@frob (sap-ref-word sap (* n-word-bytes offset)))))
(declare (inline start-bit end-bit get-word))
(with-pinned-objects (vector)
(if from-end
;; Back to front
(let* ((sap (vector-sap vector))
(word-offset last-word)
(word (logand end-mask (get-word sap word-offset))))
(declare (word word)
(index word-offset))
(unless (zerop word)
(when (= word-offset first-word)
(setf word (logand word start-mask)))
(unless (zerop word)
(found (end-bit word) word-offset)))
(decf word-offset)
(loop
(when (< word-offset first-word)
(return-from ,name nil))
(setf word (get-word sap word-offset))
(unless (zerop word)
(when (= word-offset first-word)
(setf word (logand word start-mask)))
(unless (zerop word)
(found (end-bit word) word-offset)))
(decf word-offset)))
;; Front to back
(let* ((sap (vector-sap vector))
(word-offset first-word)
(word (logand start-mask (get-word sap word-offset))))
(declare (word word)
(index word-offset))
(unless (zerop word)
(when (= word-offset last-word)
(setf word (logand word end-mask)))
(unless (zerop word)
(found (start-bit word) word-offset)))
(incf word-offset)
(loop
(when (> word-offset last-word)
(return-from ,name nil))
(setf word (get-word sap word-offset))
(unless (zerop word)
(when (= word-offset last-word)
(setf word (logand word end-mask)))
(unless (zerop word)
(found (start-bit word) word-offset)))
(incf word-offset)))))))))))
(def %bit-position/0 (logandc2 #.(1- (expt 2 n-word-bits))))
(def %bit-position/1 (identity)))
(defun %bit-position (bit vector from-end start end)
(ecase bit
(0 (%bit-position/0 vector from-end start end))
(1 (%bit-position/1 vector from-end start end))))