3位i/p移位寄存器警告

大家好。
Current Im设计3x8右移SISO
以下是我的verilog代码：
`timescale 1ns / 1psmodule ShiftReg（Clk，En，In，Out）;
参数InWidth = 3;
参数长度= 8;
输入Clk，En;
input [InWidth-1：0] In;
输出[InWidth-1：0]输出;
reg [Length-1：0] sr;
始终@（posedge Clk）开始if（En == 1'b1）begin sr [0] sr end end assign Out = sr [Length-1];
endmodule
不过这是我的警告：
警告：HDLCompiler：413  - “C： Users  User  Desktop  PE  ShiftReg  ShiftReg  ShiftReg.v”第17行：截断3位表达式的结果以适合1位目标。警告：Xst：647
- 从不使用输入。
如果该端口属于顶级块或者属于子块，则该端口将被保留并保持未连接状态，并保留该子块的层次结构。警告：Xst：1710  -  FF / Latch（无初始值）
块中的常量值为0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修整此FF / Latch。警告：Xst：1710  -  FF / Latch（无初始值）在块中具有常量值0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修整此FF / Latch。警告：Xst：1895  - 由于其他FF / Latch修整，FF / Latch（无初始值）在块中具有恒定值0。
在优化过程中将修剪此FF / Latch。
有没有人知道我的输入问题？
非常感谢你



以下为原文

Hello everyone.

Current Im designing 3x8 shift right SISO

Below is my verilog code:

`timescale 1ns / 1ps
module ShiftReg (Clk,En,In,Out);

parameter InWidth = 3;
parameter Length = 8;

input Clk,En;
input [InWidth-1:0] In;
output [InWidth-1:0] Out;
reg [Length-1:0] sr ;
always@(posedge Clk)
begin
if (En == 1'b1)
begin
sr[0] <= In;
sr <= sr<<1;
end
end

assign Out = sr[Length-1];
endmodule

However this is my warning:

WARNING:HDLCompiler:413 - "C:UsersUserDesktopPEShiftRegShiftRegShiftReg.v" Line 17: Result of 3-bit expression is truncated to fit in 1-bit target.
WARNING:Xst:647 - Input is never used. This port will be preserved and left unconnected if it belongs to a top-level block or it belongs to a sub-block and the hierarchy of this sub-block is preserved.
WARNING:Xst:1710 - FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1710 - FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch (without init value) has a constant value of 0 in block . This FF/Latch will be trimmed during the optimization process.

Does anyone have any idea for my input problem?

Thank you very much

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