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Author: curryfromuestc

src/alu.sv

@@ -6,6 +6,7 @@
 // > In this minimal implementation, the ALU supports the 4 basic arithmetic operations
 // > Each thread in each core has it's own ALU
 // > ADD, SUB, MUL, DIV instructions are all executed here
+//本模块定义了ALU的行为，包括对寄存器值的计算，支持4种基本算术运算，每个核心的每个线程都有自己的ALU，ADD，SUB，MUL，DIV指令都在这里执行
 module alu (
     input wire clk,
     input wire reset,
@@ -20,7 +21,7 @@ module alu (
     input reg [7:0] rt,
     output wire [7:0] alu_out
 );
-    localparam ADD = 2'b00,
+    localparam ADD = 2'b00, //定义了4种基本算术运算对应的编码，且采用了本地参数
         SUB = 2'b01,
         MUL = 2'b10,
         DIV = 2'b11;
@@ -36,9 +37,9 @@ module alu (
             if (core_state == 3'b101) begin 
                 if (decoded_alu_output_mux == 1) begin 
                     // Set values to compare with NZP register in alu_out[2:0]
-                    alu_out_reg <= {5'b0, (rs - rt > 0), (rs - rt == 0), (rs - rt < 0)};
+                    alu_out_reg <= {5'b0, (rs - rt > 0), (rs - rt == 0), (rs - rt < 0)}; //alu_out的低3位分别存储了NZP寄存器的值
                 end else begin 
-                    // Execute the specified arithmetic instruction
+                    // Execute the specified arithmetic instruction //执行指定的算术指令
                     case (decoded_alu_arithmetic_mux)
                         ADD: begin 
                             alu_out_reg <= rs + rt;