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24
Kit: A Study in Operating System Verification
, 1989
"... Kernel Implements Processes The relationship between the abstract kernel and an individual task is pictured in Figure 4, and is formalized by the theorem AKIMPLEMENTSPARALLELTASKS. Intuitively, this theorem says that for a given good abstract kernel state AK and abstract kernel oracle ORACLE, th ..."
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Cited by 59 (0 self)
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Kernel Implements Processes The relationship between the abstract kernel and an individual task is pictured in Figure 4, and is formalized by the theorem AKIMPLEMENTSPARALLELTASKS. Intuitively, this theorem says that for a given good abstract kernel state AK and abstract kernel oracle ORACLE, the final state reached by task I can equivalently be achieved by running TASKPROCESSOR on the initial task state, with an oracle constructed by the function CONTROLORACLE. The oracle constructed for TASKPROCESSOR accounts for the precise sequence of delays to task I in the abstract kernel. Task project AK Figure 4: AK Implements Parallel Tasks THEOREM AKIMPLEMENTSPARALLELTASKS (IMPLIES (AND (GOODAK AK) (FINITENUMBERP I (LENGTH (AKPSTATES AK)))) (EQUAL (PROJECT I (AKPROCESSOR AK ORACLE)) (TASKPROCESSOR (PROJECT I AK) I (CONTROLORACLE I AK ORACLE)))) 6. The Target Machine The target machine TM is a simple von Neumann computer. It is not based on an existing physical machine becaus...
ACL2: An Industrial Strength Version of Nqthm
, 1996
"... ACL2 is a reimplemented extended version of Boyer and Moore's Nqthm and Kaufmann's PcNqthm, intended for large scale verification projects. However, the logic supported by ACL2 is compatible with the applicative subset of Common Lisp. The decision to use an "industrial strength" programming languag ..."
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Cited by 58 (5 self)
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ACL2 is a reimplemented extended version of Boyer and Moore's Nqthm and Kaufmann's PcNqthm, intended for large scale verification projects. However, the logic supported by ACL2 is compatible with the applicative subset of Common Lisp. The decision to use an "industrial strength" programming language as the foundation of the mathematical logic is crucial to our advocacy of ACL2 in the application of formal methods to large systems. However, one of the key reasons Nqthm has been so successful, we believe, is its insistence that functions be total. Common Lisp functions are not total and this is one of the reasons Common Lisp is so efficient. This paper explains how we scaled up Nqthm's logic to Common Lisp, preserving the use of total functions within the logic but achieving Common Lisp execution speeds. 1 History ACL2 is a direct descendent of the BoyerMoore system, Nqthm [8, 12], and its interactive enhancement, PcNqthm [21, 22, 23]. See [7, 25] for introductions to the two ancestr...
Design Goals for ACL2
, 1994
"... ACL2 is a theorem proving system under development at Computational Logic, Inc., by the authors of the BoyerMoore system, Nqthm, and its interactive enhancement, PcNqthm, based on our perceptions of some of the inadequacies of Nqthm when used in largescale verification projects. Foremost among th ..."
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Cited by 36 (5 self)
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ACL2 is a theorem proving system under development at Computational Logic, Inc., by the authors of the BoyerMoore system, Nqthm, and its interactive enhancement, PcNqthm, based on our perceptions of some of the inadequacies of Nqthm when used in largescale verification projects. Foremost among those inadequacies is the fact that Nqthm's logic is an inefficient programming language. We now recognize that the efficiency of the logic as a programming language is of great importance because the models of microprocessors, operating systems, and languages typically constructed in verification projects must be executed to corroborate them against the realities they model. Simulation of such large scale systems stresses the logic in ways not imagined when Nqthm was designed. In addition, Nqthm does not adequately support certain proof techniques, nor does it encourage the reuse of previously developed libraries or the collaboration of semiautonomous workers on different parts of a verifica...
Automated Correctness Proofs of Machine Code Programs for a Commercial Microprocessor
, 1991
"... We have formally specified a substantial subset of the MC68020, a widely used microprocessor built by Motorola, within the mathematical logic of the automated reasoning system Nqthm, i.e., the BoyerMoore Theorem Prover [4]. Using this MC68020 specification, we have mechanically checked the correctn ..."
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Cited by 32 (2 self)
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We have formally specified a substantial subset of the MC68020, a widely used microprocessor built by Motorola, within the mathematical logic of the automated reasoning system Nqthm, i.e., the BoyerMoore Theorem Prover [4]. Using this MC68020 specification, we have mechanically checked the correctness of MC68020 machine code programs for Euclid's GCD, Hoare's Quick Sort, binary search, and other wellknown algorithms. The machine code for these examples was generated using the Gnu C and the Verdix Ada compilers. We have developed an extensive library of proven lemmas to facilitate automated reasoning about machine code programs. We describe a two stage methodology we use to do our machine code proofs.
The BoyerMoore Theorem Prover and Its Interactive Enhancement
, 1995
"... . The socalled "BoyerMoore Theorem Prover" (otherwise known as "Nqthm") has been used to perform a variety of verification tasks for two decades. We give an overview of both this system and an interactive enhancement of it, "PcNqthm," from a number of perspectives. First we introduce the logic in ..."
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. The socalled "BoyerMoore Theorem Prover" (otherwise known as "Nqthm") has been used to perform a variety of verification tasks for two decades. We give an overview of both this system and an interactive enhancement of it, "PcNqthm," from a number of perspectives. First we introduce the logic in which theorems are proved. Then we briefly describe the two mechanized theorem proving systems. Next, we present a simple but illustrative example in some detail in order to give an impression of how these systems may be used successfully. Finally, we give extremely short descriptions of a large number of applications of these systems, in order to give an idea of the breadth of their uses. This paper is intended as an informal introduction to systems that have been described in detail and similarly summarized in many other books and papers; no new results are reported here. Our intention here is merely to present Nqthm to a new audience. This research was supported in part by ONR Contract N...
A Theorem Prover for a Computational Logic
, 1990
"... We briefly review a mechanical theoremprover for a logic of recursive functions over finitely generated objects including the integers, ordered pairs, and symbols. The prover, known both as NQTHM and as the BoyerMoore prover, contains a mechanized principle of induction and implementations of line ..."
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Cited by 24 (0 self)
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We briefly review a mechanical theoremprover for a logic of recursive functions over finitely generated objects including the integers, ordered pairs, and symbols. The prover, known both as NQTHM and as the BoyerMoore prover, contains a mechanized principle of induction and implementations of linear resolution, rewriting, and arithmetic decision procedures. We describe some applications of the prover, including a proof of the correct implementation of a higher level language on a microprocessor defined at the gate level. We also describe the ongoing project of recoding the entire prover as an applicative function within its own logic.
A Verified Code Generator For A Subset Of Gypsy
, 1988
"... A VERIFIED CODE GENERATOR FOR A SUBSET OF GYPSY Publication No. William David Young, Ph.D. The University of Texas at Austin, 1988 Supervising Professors: Robert S. Boyer, J Strother Moore This report describes the specification and mechanical proof of a code generator for a subset of Gypsy 2.05 cal ..."
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Cited by 22 (4 self)
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A VERIFIED CODE GENERATOR FOR A SUBSET OF GYPSY Publication No. William David Young, Ph.D. The University of Texas at Austin, 1988 Supervising Professors: Robert S. Boyer, J Strother Moore This report describes the specification and mechanical proof of a code generator for a subset of Gypsy 2.05 called MicroGypsy. MicroGypsy is a highlevel language containing many of the Gypsy control structures, simple data types and arrays, and predefined and userdefined procedure definitions including recursive procedure definitions. The language is formally specified by a recognizer and interpreter written as functions in the BoyerMoore logic. The target language for the MicroGypsy code generator is the Piton highlevel assembly language verified by J Moore to be correctly implemented on the FM8502 hardware. The semantics of Piton is specified by another interpreter written in the logic. A BoyerMoore function maps a MicroGypsy state containing program and data structures into an initial Pit...
A Grand Challenge Proposal for Formal Methods: A Verified Stack
"... We propose a grand challenge for the formal methods community: build and mechanically verify a practical embedded system, from transistors to software. We propose that each group within the formal methods community design and verify, by the methods appropriate to that group, an embedded system of ..."
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Cited by 20 (1 self)
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We propose a grand challenge for the formal methods community: build and mechanically verify a practical embedded system, from transistors to software. We propose that each group within the formal methods community design and verify, by the methods appropriate to that group, an embedded system of their choice. The point is not to have just one integrated formal method or just one verified application, but to encourage groups to develop the techniques and methodologies necessary for systemlevel verification.
Hoare logic for realistically modelled machine code
 In Tools and Algorithms for the Construction and Analysis of Systems (TACAS 2007), LNCS
, 2007
"... Abstract. This paper presents a mechanised Hoarestyle programming logic framework for assembly level programs. The framework has been designed to fit on top of operational semantics of realistically modelled machine code. Many ad hoc restrictions and features present in real machinecode are handle ..."
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Cited by 18 (5 self)
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Abstract. This paper presents a mechanised Hoarestyle programming logic framework for assembly level programs. The framework has been designed to fit on top of operational semantics of realistically modelled machine code. Many ad hoc restrictions and features present in real machinecode are handled, including finite memory, data and code in the same memory space, the behavior of status registers and hazards of corrupting special purpose registers (e.g. the program counter, procedure return register and stack pointer). Despite accurately modeling such low level details, the approach yields concise specifications for machinecode programs without using common simplifying assumptions (like an unbounded state space). The framework is based on a flexible state representation in which functional and resource usage specifications are written in a style inspired by separation logic. The presented work has been formalised in higherorder logic, mechanised in the HOL4 system and is currently being used to verify ARM machinecode implementations of arithmetic and cryptographic operations. 1