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; X86ISA Library
; Note: The license below is based on the template at:
; http://opensource.org/licenses/BSD-3-Clause
; Copyright (C) 2015, Regents of the University of Texas
; All rights reserved.
; Redistribution and use in source and binary forms, with or without
; modification, are permitted provided that the following conditions are
; met:
; o Redistributions of source code must retain the above copyright
; notice, this list of conditions and the following disclaimer.
; o Redistributions in binary form must reproduce the above copyright
; notice, this list of conditions and the following disclaimer in the
; documentation and/or other materials provided with the distribution.
; o Neither the name of the copyright holders nor the names of its
; contributors may be used to endorse or promote products derived
; from this software without specific prior written permission.
; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
; A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
; HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
; SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
; LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
; DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
; THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
; OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
; Original Author(s):
; Shilpi Goel <shigoel@cs.utexas.edu>
(in-package "X86ISA")
;; This book contains the specification of the following instructions:
;; sub sbb
(include-book "structures" :dir :utils)
(include-book "../rflags-spec"
:ttags (:undef-flg))
(local (include-book "centaur/bitops/ihs-extensions" :dir :system))
;; ======================================================================
;; SPECIFICATION: SUB
;; ======================================================================
;; The SUB instruction performs integer subtraction. It evaluates the
;; result for both signed and unsigned integer operands and sets the
;; OF and CF flags to indicate an overflow in the signed or unsigned
;; result, respectively. The SF flag indicates the sign of the signed
;; result.
;; (def-gl-thm sub-signed-and-unsigned-check
;; :hyp (and (n32p x)
;; (n32p y))
;; :concl (equal (n32 (- (n32-to-i32 x) (n32-to-i32 y)))
;; (n32 (- x y)))
;; :g-bindings `((x (:g-number ,(gl-int 0 2 33)))
;; (y (:g-number ,(gl-int 1 2 33)))))
(define gpr-sub-spec-gen-fn ((operand-size :type (member 1 2 4 8)))
:verify-guards nil
(b* ((fn-name (mk-name "GPR-SUB-SPEC-" operand-size))
(result-nbits (ash operand-size 3))
(str-nbits (if (eql result-nbits 8) "08" result-nbits))
(ntoi (mk-name "N" str-nbits "-TO-I" str-nbits))
(?cf-spec-fn (mk-name "CF-SPEC" result-nbits))
(pf-spec-fn (mk-name "PF-SPEC" result-nbits))
(af-spec-fn (mk-name "SUB-AF-SPEC" result-nbits))
(sf-spec-fn (mk-name "SF-SPEC" result-nbits))
(of-spec-fn (mk-name "OF-SPEC" result-nbits)))
`(define ,fn-name
((dst :type (unsigned-byte ,result-nbits))
(src :type (unsigned-byte ,result-nbits))
(input-rflags :type (unsigned-byte 32)))
:parents (,(mk-name "GPR-ARITH/LOGIC-SPEC-" operand-size))
:guard-hints (("Goal" :in-theory (e/d* (rflag-RoWs-enables)
((tau-system)))))
:inline t
:no-function t
(b* ((dst (mbe :logic (n-size ,result-nbits dst)
:exec dst))
(src (mbe :logic (n-size ,result-nbits src)
:exec src))
(input-rflags (mbe :logic (n32 input-rflags)
:exec input-rflags))
(signed-raw-result
(the (signed-byte ,(1+ result-nbits))
(- (the (signed-byte ,result-nbits)
(,ntoi dst))
(the (signed-byte ,result-nbits)
(,ntoi src)))))
(result (the (unsigned-byte ,result-nbits)
(n-size ,result-nbits signed-raw-result)))
(cf (the (unsigned-byte 1) (acl2::bool->bit (< dst src))))
(pf (the (unsigned-byte 1) (,pf-spec-fn result)))
(af (the (unsigned-byte 1) (,af-spec-fn dst src)))
(zf (the (unsigned-byte 1) (zf-spec result)))
(sf (the (unsigned-byte 1) (,sf-spec-fn result)))
(of (the (unsigned-byte 1) (,of-spec-fn signed-raw-result)))
(output-rflags (mbe :logic
(change-rflagsBits
input-rflags
:cf cf
:pf pf
:af af
:zf zf
:sf sf
:of of)
:exec
(the (unsigned-byte 32)
(!rflagsBits->cf
cf
(!rflagsBits->pf
pf
(!rflagsBits->af
af
(!rflagsBits->zf
zf
(!rflagsBits->sf
sf
(!rflagsBits->of
of
input-rflags)))))))))
(output-rflags (mbe :logic (n32 output-rflags)
:exec output-rflags))
(undefined-flags 0))
(mv result output-rflags undefined-flags))
///
(defthm-unsigned-byte-p ,(mk-name "N" str-nbits "-MV-NTH-0-" fn-name)
:bound ,result-nbits
:concl (mv-nth 0 (,fn-name dst src input-rflags))
:gen-type t
:gen-linear t)
(defthm-unsigned-byte-p ,(mk-name "MV-NTH-1-" fn-name)
:bound 32
:concl (mv-nth 1 (,fn-name dst src input-rflags))
:gen-type t
:gen-linear t)
(defthm-unsigned-byte-p ,(mk-name "MV-NTH-2-" fn-name)
:bound 32
:concl (mv-nth 2 (,fn-name dst src input-rflags))
:gen-type t
:gen-linear t))))
(make-event (gpr-sub-spec-gen-fn 1))
(make-event (gpr-sub-spec-gen-fn 2))
(make-event (gpr-sub-spec-gen-fn 4))
(make-event (gpr-sub-spec-gen-fn 8))
;; ======================================================================
;; SPECIFICATION: SBB
;; ======================================================================
(define gpr-sbb-spec-gen-fn ((operand-size :type (member 1 2 4 8)))
:verify-guards nil
(b* ((fn-name (mk-name "GPR-SBB-SPEC-" operand-size))
(result-nbits (ash operand-size 3))
(str-nbits (if (eql result-nbits 8) "08" result-nbits))
(ntoi (mk-name "N" str-nbits "-TO-I" str-nbits))
(?cf-spec-fn (mk-name "CF-SPEC" result-nbits))
(pf-spec-fn (mk-name "PF-SPEC" result-nbits))
(af-spec-fn (mk-name "SBB-AF-SPEC" result-nbits))
(sf-spec-fn (mk-name "SF-SPEC" result-nbits))
(of-spec-fn (mk-name "OF-SPEC" result-nbits)))
`(define ,fn-name
((dst :type (unsigned-byte ,result-nbits))
(src :type (unsigned-byte ,result-nbits))
(input-rflags :type (unsigned-byte 32)))
:parents (,(mk-name "GPR-ARITH/LOGIC-SPEC-" operand-size))
:guard-hints (("Goal" :in-theory (e/d* (rflag-RoWs-enables)
((tau-system)))))
:inline t
:no-function t
(b* ((dst (mbe :logic (n-size ,result-nbits dst)
:exec dst))
(src (mbe :logic (n-size ,result-nbits src)
:exec src))
(input-rflags (mbe :logic (n32 input-rflags)
:exec input-rflags))
(input-cf (the (unsigned-byte 1)
(rflagsBits->cf input-rflags)))
(signed-raw-result
(the (signed-byte ,(+ 2 result-nbits))
(- (the (signed-byte ,result-nbits)
(,ntoi dst))
(the (signed-byte ,(1+ result-nbits))
(+ (the (signed-byte ,result-nbits)
(,ntoi src))
input-cf)))))
(result (the (unsigned-byte ,result-nbits)
(n-size ,result-nbits signed-raw-result)))
(cf (the (unsigned-byte 1)
(acl2::bool->bit
(< dst
(the (unsigned-byte ,(1+ result-nbits))
(+ input-cf src))))))
(pf (the (unsigned-byte 1) (,pf-spec-fn result)))
(af (the (unsigned-byte 1) (,af-spec-fn dst src input-cf)))
(zf (the (unsigned-byte 1) (zf-spec result)))
(sf (the (unsigned-byte 1) (,sf-spec-fn result)))
(of (the (unsigned-byte 1) (,of-spec-fn signed-raw-result)))
(output-rflags (mbe :logic
(change-rflagsBits
input-rflags
:cf cf
:pf pf
:af af
:zf zf
:sf sf
:of of)
:exec
(the (unsigned-byte 32)
(!rflagsBits->cf
cf
(!rflagsBits->pf
pf
(!rflagsBits->af
af
(!rflagsBits->zf
zf
(!rflagsBits->sf
sf
(!rflagsBits->of
of
input-rflags)))))))))
(output-rflags (mbe :logic (n32 output-rflags)
:exec output-rflags))
(undefined-flags 0))
(mv result output-rflags undefined-flags))
///
(defthm-unsigned-byte-p ,(mk-name "N" str-nbits "-MV-NTH-0-" fn-name)
:bound ,result-nbits
:concl (mv-nth 0 (,fn-name dst src cf))
:gen-type t
:gen-linear t)
(defthm-unsigned-byte-p ,(mk-name "MV-NTH-1-" fn-name)
:bound 32
:concl (mv-nth 1 (,fn-name dst src input-rflags))
:gen-type t
:gen-linear t)
(defthm-unsigned-byte-p ,(mk-name "MV-NTH-2-" fn-name)
:bound 32
:concl (mv-nth 2 (,fn-name dst src input-rflags))
:gen-type t
:gen-linear t))))
(make-event (gpr-sbb-spec-gen-fn 1))
(make-event (gpr-sbb-spec-gen-fn 2))
(make-event (gpr-sbb-spec-gen-fn 4))
(make-event (gpr-sbb-spec-gen-fn 8))
;; ======================================================================
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