一、carry的构成
二、carry8的例化及端口功能说明
CARRY8 #(
.CARRY_TYPE("SINGLE_CY8") // 8-bit or dual 4-bit carry (DUAL_CY4, SINGLE_CY8)
)
CARRY8_inst (
.CO(CO), // 8-bit output: Carry-out
.O(O), // 8-bit output: Carry chain XOR data out
.CI(CI), // 1-bit input: Lower Carry-In
.CI_TOP(CI_TOP), // 1-bit input: Upper Carry-In
.DI(DI), // 8-bit input: Carry-MUX data in
.S(S) // 8-bit input: Carry-mux select
);
三、carry8的内部架构
参考ug574第23页