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; Centaur Bitops Library
; Copyright (C) 2010-2011 Centaur Technology
;
; Contact:
; Centaur Technology Formal Verification Group
; 7600-C N. Capital of Texas Highway, Suite 300, Austin, TX 78731, USA.
; http://www.centtech.com/
;
; License: (An MIT/X11-style license)
;
; Permission is hereby granted, free of charge, to any person obtaining a
; copy of this software and associated documentation files (the "Software"),
; to deal in the Software without restriction, including without limitation
; the rights to use, copy, modify, merge, publish, distribute, sublicense,
; and/or sell copies of the Software, and to permit persons to whom the
; Software is furnished to do so, subject to the following conditions:
;
; The above copyright notice and this permission notice shall be included in
; all copies or substantial portions of the Software.
;
; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
; FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
; DEALINGS IN THE SOFTWARE.
;
; Original author: Jared Davis <jared@centtech.com>
(in-package "BITOPS")
(include-book "xdoc/top" :dir :system)
(include-book "ihs/basic-definitions" :dir :system)
(local (include-book "arithmetic/top-with-meta" :dir :system))
(local (include-book "ihsext-basics"))
(local (include-book "std/testing/assert-bang" :dir :system))
(defsection bitops/part-select
:parents (bitops)
:short "This book provides a readable nice macro for extracting a portion of
an integer. You could use it to, e.g., extract bits 15-8 as a byte.")
(defsection part-select
:parents (bitops/part-select)
:short "Select a portion of bits from an integer that represents a bit
vector"
:long "<p>@('part-select') is a macro that lets you write code to extract
parts of vectors. For instance:</p>
@({
(part-select foo :low 10 :high 17) ;; Like foo[17:10] in Verilog
})
<p>You can also using an index/size, e.g.:</p>
@({
(part-select foo :low 10 :width 7) ;; Like foo[16:10] in Verilog
})
@(def part-select)"
(defun-inline part-select-width-low (x width low)
"Don't call this directly -- use the part-select macro instead."
(declare (xargs :guard (and (integerp x)
(natp width)
(natp low))))
(mbe :logic (loghead width (logtail low x))
:exec (logand (1- (ash 1 width))
(ash x (- low)))))
(defun-inline part-select-low-high (x low high)
"Don't call this directly -- use the part-select macro instead."
(declare (xargs :guard (and (integerp x)
(natp low)
(natp high)
(<= low high))))
(part-select-width-low x (+ 1 (- high low)) low))
(defmacro part-select (x &key low high width)
(cond ((and high width)
(er hard? 'part-select "Can't use :high and :width together"))
((and low high)
`(part-select-low-high ,x ,low ,high))
((and low width)
`(part-select-width-low ,x ,width ,low))
(t
(er hard? 'part-select
"Need at least :low and :width, or else :low and :high"))))
(add-macro-alias part-select part-select-width-low$inline))
(local
(progn
(assert! (equal (part-select #ux_AAAA_BBBB_CCCC_DDDD :low 0 :width 16) #ux_DDDD))
(assert! (equal (part-select #ux_AAAA_BBBB_CCCC_DDDD :low 16 :width 16) #ux_CCCC))
(assert! (equal (part-select #ux_AAAA_BBBB_CCCC_DDDD :low 32 :width 16) #ux_BBBB))
(assert! (equal (part-select #ux_AAAA_BBBB_CCCC_DDDD :low 48 :width 16) #ux_AAAA))
(assert! (equal (part-select #ux_AAAA_BBBB_CCCC_DDDD :low 0 :high 15) #ux_DDDD))
(assert! (equal (part-select #ux_AAAA_BBBB_CCCC_DDDD :low 16 :high 31) #ux_CCCC))
(assert! (equal (part-select #ux_AAAA_BBBB_CCCC_DDDD :low 32 :high 47) #ux_BBBB))
(assert! (equal (part-select #ux_AAAA_BBBB_CCCC_DDDD :low 48 :high 63) #ux_AAAA))))
(defun ccl-bug-1273-test (n)
(declare (type (unsigned-byte 80) n))
(part-select n :low 64 :high 78))
(make-event
(progn$ (or (equal (ccl-bug-1273-test (1- (expt 2 80))) 32767)
(cw "~%~%WARNING (centaur/bitops/part-select.lisp): CCL Bug 1273 Detected!~%~
Please upgrade CCL to Version 16356 or later. For details see:~% ~
- http://trac.clozure.com/ccl/ticket/1273~% ~
- http://trac.clozure.com/ccl/changeset/16356~%~%"))
'(value-triple :invisible))
:check-expansion t)
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