Formal Verification of Hardware Components in Critical Systems

Listing 22

Formal definition of 4-bit BCD adder (with look-ahead carry).

(1)	Definition BCDadderLA (D C B A d c b a e:bool) : circuit
(2)	let t1 FA4bitLA D C B A d c b a e in
(3)	let outcarry FST t1 (SND t1)(TRD t1) (SND t1)(FRT t1) in
(4)	let t2
(5)	FA4bitLA (SND t1) (TRD t1) (FRT t1) (FFT t1) false outcarry outcarry false e in
(6)	[outcarry; SND t2; TRD t2; FRT t2; FFT t2].