input [7:0] minuend;
input [7:0] subtrahend;
output [7:0] difference;
wire inv_subtrahend_7;
wire inv_subtrahend_6;
wire inv_subtrahend_5;
wire inv_subtrahend_4;
wire inv_subtrahend_3;
wire inv_subtrahend_2;
wire inv_subtrahend_1;
wire inv_subtrahend_0;
wire negator_carry_0;
wire negator_carry_1;
wire negator_carry_2;
wire negator_carry_3;
wire negator_carry_4;
wire negator_carry_5;
wire negator_carry_6;
wire negator_carry_7;
wire neg_subtrahend_7;
wire neg_subtrahend_6;
wire neg_subtrahend_5;
wire neg_subtrahend_4;
wire neg_subtrahend_3;
wire neg_subtrahend_2;
wire neg_subtrahend_1;
wire neg_subtrahend_0;
assign inv_subtrahend_7 = ~ subtrahend[7];
assign inv_subtrahend_6 = ~ subtrahend[6];
assign inv_subtrahend_5 = ~ subtrahend[5];
assign inv_subtrahend_4 = ~ subtrahend[4];
assign inv_subtrahend_3 = ~ subtrahend[3];
assign inv_subtrahend_2 = ~ subtrahend[2];
assign inv_subtrahend_1 = ~ subtrahend[1];
assign inv_subtrahend_0 = ~ subtrahend[0];
assign negator_carry_0 = inv_subtrahend_0;
assign negator_carry_1 = negator_carry_0 & inv_subtrahend_1;
assign negator_carry_2 = negator_carry_1 & inv_subtrahend_2;
assign negator_carry_3 = negator_carry_2 & inv_subtrahend_3;
assign negator_carry_4 = negator_carry_3 & inv_subtrahend_4;
assign negator_carry_5 = negator_carry_4 & inv_subtrahend_5;
assign negator_carry_6 = negator_carry_5 & inv_subtrahend_6;
assign negator_carry_7 = negator_carry_6 & inv_subtrahend_7;
assign neg_subtrahend_0 = ~ inv_subtrahend_0;
assign neg_subtrahend_1 = negator_carry_0 ^ inv_subtrahend_1;
assign neg_subtrahend_2 = negator_carry_1 ^ inv_subtrahend_2;
assign neg_subtrahend_3 = negator_carry_2 ^ inv_subtrahend_3;
assign neg_subtrahend_4 = negator_carry_3 ^ inv_subtrahend_4;
assign neg_subtrahend_5 = negator_carry_4 ^ inv_subtrahend_5;
assign neg_subtrahend_6 = negator_carry_5 ^ inv_subtrahend_6;
assign neg_subtrahend_7 = negator_carry_6 ^ inv_subtrahend_7;
assign difference[0] = minuend[0] ^ neg_subtrahend_0;
assign difference[1] = minuend[1] ^ neg_subtrahend_1;
assign difference[2] = minuend[2] ^ neg_subtrahend_2;
assign difference[3] = minuend[3] ^ neg_subtrahend_3;
assign difference[4] = minuend[4] ^ neg_subtrahend_4;
assign difference[5] = minuend[5] ^ neg_subtrahend_5;
assign difference[6] = minuend[6] ^ neg_subtrahend_6;
assign difference[7] = minuend[7] ^ neg_subtrahend_7;
补码减法
我否定了减数并确保进位通过了，但是我坚持到底出了什么问题。最后的异或运算应该使用被减数和取反的减数执行减法，但我似乎找不到我哪里出错了。