Formal Verification of Hardware Components in Critical Systems

Listing 19

Formal definition of 4-bit binary parallel adder (without look-ahead carry).

(1)	Definition fa (a A e: bool) : (boolbool)
(2)	(Aa(Aa)e,Aae).
(3)	Definition FA (f: boolboolbool(boolbool)) (a A e: bool)
(4)	: (boolbool) fa a A e.
(5)	Definition FA4bit (D C B A d c b a e: bool)
(6)	: (boolboolboolboolbool)
(7)	let ss1 snd(FA fa a A e) in
(8)	let cc1 fst(FA fa a A e) in
(9)	let ss2 snd(FA fa b B cc1) in
(10)	let cc2 fst(FA fa b B cc1) in
(11)	let ss3 snd(FA fa c C cc2) in
(12)	let cc3 fst(FA fa c C cc2) in
(13)	let ss4 snd(FA fa d D cc3) in
(14)	let cc4 fst(FA fa d D cc3) in
(15)	(cc4,ss4,ss3,ss2,ss1).