fieldAdd(f[start+3], t) } for start := 0; start < 256; start += 4 { m++ zeta := zetas[m] t := fieldMontgomeryMul(zeta, f[start+2]) f[start+2] = fieldSub(f[start], t) f[start] = fieldAdd(f[start], t) t = fieldMontgomeryMul(zeta, f[start+3]) f[start+3] = fieldSub(f[start+1], t) f[start+1] = fieldAdd(f[start+1], t) } for start := 0; start < 256; start += 2 { m++ zeta := zetas[m] t := fieldMontgomeryMul(zeta, f[start+1]) f[start+1] = fieldSub(f[start], t) f[start] = fieldAdd(f[start], t) } return nttElement(f)...