/usr/share/acl2-4.3/books/unicode/combine.lisp is in acl2-books-source 4.3-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 | ;; Processing Unicode Files with ACL2
;; Copyright (C) 2005-2006 by Jared Davis <jared@cs.utexas.edu>
;;
;; This program is free software; you can redistribute it and/or modify it
;; under the terms of the GNU General Public License as published by the Free
;; Software Foundation; either version 2 of the License, or (at your option)
;; any later version.
;;
;; This program is distributed in the hope that it will be useful but WITHOUT
;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
;; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
;; more details.
;;
;; You should have received a copy of the GNU General Public License along with
;; this program; if not, write to the Free Software Foundation, Inc., 59 Temple
;; Place - Suite 330, Boston, MA 02111-1307, USA.
(in-package "ACL2")
(set-verify-guards-eagerness 2)
(include-book "sign-byte")
(local (include-book "unsigned-byte-listp"))
(local (include-book "signed-byte-listp"))
(defun combine16u (x1 x2)
"Given unsigned bytes x1 and x2, compute (x1 << 8) | x2, interpreted
as a 16-bit unsigned integer."
(declare (type (unsigned-byte 8) x1)
(type (unsigned-byte 8) x2))
(logior (ash x1 8) x2))
(defthm combine16u-unsigned-byte
(implies (and (force (unsigned-byte-p 8 x1))
(force (unsigned-byte-p 8 x2)))
(unsigned-byte-p 16 (combine16u x1 x2))))
(in-theory (disable combine16u))
(defun combine16s (x1 x2)
"Given unsigned bytes x1 and x2, compute (x1 << 8) | x2, interpreted
as a 16-bit signed integer."
(declare (type (unsigned-byte 8) x1)
(type (unsigned-byte 8) x2))
(logior (ash (sign-byte x1) 8)
x2))
(defthm combine16s-signed-byte
(implies (and (force (unsigned-byte-p 8 x1))
(force (unsigned-byte-p 8 x2)))
(signed-byte-p 16 (combine16s x1 x2))))
(in-theory (disable combine16s))
(defun combine32u (x1 x2 x3 x4)
"Given unsigned bytes x1, x2, x3, and x4, compute
(x1 << 24) | (x2 << 16) | (x3 << 8) | x4
and interpret the result as a 32-bit unsigned integer."
(declare (type (unsigned-byte 8) x1)
(type (unsigned-byte 8) x2)
(type (unsigned-byte 8) x3)
(type (unsigned-byte 8) x4))
(logior (ash x1 24)
(ash x2 16)
(ash x3 8)
x4))
(defthm combine32u-unsigned-byte
(implies (and (force (unsigned-byte-p 8 x1))
(force (unsigned-byte-p 8 x2))
(force (unsigned-byte-p 8 x3))
(force (unsigned-byte-p 8 x4)))
(unsigned-byte-p 32 (combine32u x1 x2 x3 x4))))
(in-theory (disable combine32u))
(defun combine32s (x1 x2 x3 x4)
"Given unsigned bytes x1, x2, x3, and x4, compute
(x1 << 24) | (x2 << 16) | (x3 << 8) | x4
and interpret the result as an 32-bit signed integer."
(declare (type (unsigned-byte 8) x1)
(type (unsigned-byte 8) x2)
(type (unsigned-byte 8) x3)
(type (unsigned-byte 8) x4))
(logior (ash (sign-byte x1) 24)
(ash x2 16)
(ash x3 8)
x4))
(defthm combine32s-signed-byte
(implies (and (force (unsigned-byte-p 8 x1))
(force (unsigned-byte-p 8 x2))
(force (unsigned-byte-p 8 x3))
(force (unsigned-byte-p 8 x4)))
(signed-byte-p 32 (combine32s x1 x2 x3 x4)))
:hints(("Goal" :use ((:instance signed-byte-p-logior
(size 32)
(x (ash (sign-byte x1) 24))
(y (logior (ash x2 16)
(ash x3 8)
x4)))
(:instance unsigned-to-signed-promote
(size1 24)
(size2 32)
(x (logior (ash x2 16)
(ash x3 8)
x4)))))))
(in-theory (disable combine32s))
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