问个流水线加法器的问题
时间：10-02
整理：3721RD
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module adder8_2(cout ,sum ,clk ,cina ,cinb ,cin) ;
input [7 :0]cina ,cinb;
input clk ,cin;
output [7 :0] sum;
output cout;
reg cout ;
reg cout1 ;
reg[3 :0]sum1;
reg[7 :0]sum;
always @(posedge clk) begin //第4 位相加;
{cout1 , sum1} = cina [3 : 0] + cinb [3 : 0] + cin ;
end
always @(posedge clk) begin //高4 位相加,并且将8 位拼接起来;
{cout ,sum} = {{cina[7],cina [7 :4]} +{cinb[7], cinb[7 :4] + cout1} ,sum1};
end
endmodule
一个2级流水线的加法看不懂这一句{cout ,sum} = {{cina[7],cina [7 :4]} +{cinb[7], cinb[7 :4] + cout1} ,sum1};
cina[7]是什么意思?
input [7 :0]cina ,cinb;
input clk ,cin;
output [7 :0] sum;
output cout;
reg cout ;
reg cout1 ;
reg[3 :0]sum1;
reg[7 :0]sum;
always @(posedge clk) begin //第4 位相加;
{cout1 , sum1} = cina [3 : 0] + cinb [3 : 0] + cin ;
end
always @(posedge clk) begin //高4 位相加,并且将8 位拼接起来;
{cout ,sum} = {{cina[7],cina [7 :4]} +{cinb[7], cinb[7 :4] + cout1} ,sum1};
end
endmodule
一个2级流水线的加法看不懂这一句{cout ,sum} = {{cina[7],cina [7 :4]} +{cinb[7], cinb[7 :4] + cout1} ,sum1};
cina[7]是什么意思?
符号位扩展啊，结果要比输入多一位的
always @(posedge clk) begin //高4 位相加,并且将8 位拼接起来;
{cout ,sum} = {{cina[7],cina [7 :4]} +{cinb[7], cinb[7 :4] + cout1} ,sum1};
看不懂谁告诉下?
如果要实现2级流水加法的话
{cout ,sum} = {{1'b0,cina [7 :4]} +{1'b0,cinb[7 :4] + cout1} ,sum1};
否则的话实现的就不是2个数相加了
2楼很对
就是符号位扩展
{cout ,sum} = {{cina[7],cina [7 :4]} +{cinb[7], cinb[7 :4] + cout1} ,sum1};
是怎么实现8位链接的?
{cina[7],cina [7 :4]} +{cinb[7], cinb[7 :4] + cout1}能具体解释下么
{cina[7],cina [7 :4]}
+{cinb[7], cinb[7 :4]}
+ cout1
=进位，和的高4位