source 2007 Hisil--Carter--Dawson
parameter b
assume b = a - 1
compute R0 = S1^2
compute R1 = C1^2
compute R2 = R0^2
compute R3 = R1^2
compute R4 = 2 R3
compute R5 = 2 R4
compute R6 = 2 R1
compute R6 = R6+R0
compute R6 = R6^2
compute R6 = R6-R2
compute R6 = R6-R5
compute R2 = b R2
compute R5 = R5+R4
compute R4 = R2^2
compute R0 = R5 R2
compute R5 = R2 R6
compute R2 = R3^2
compute R1 = R3 R6
compute R3 = R4-R2
compute R2 = R4+R2
compute R4 = 2 R3
compute R3 = b R1
compute R6 = b R5
compute R3 = R0+R3
compute R1 = R1+R2
compute R0 = R0-R6
compute R2 = R5-R2
compute R5 = R3+R4
compute R5 = R5-R1
compute S3 = S1 R5
compute R4 = R4-R2
compute R4 = R4-R0
compute C3 = C1 R4
compute R2 = R2+R3
compute D3 = D1 R2
compute R0 = R0-R1
compute Z3 = Z1 R0
compute SC3 = S3 C3
compute DZ3 = D3 Z3