From 464289c73853f13f6ccc4b584503c4c09988d1a0 Mon Sep 17 00:00:00 2001
From: dianshi <dianshi@main.lv>
Date: Mon, 14 Feb 2022 08:04:19 +0000
Subject: Add alu v0.1_16bit. compiles without warning risc cpu

---
 alu/v0.1_16bit/Makefile        |  9 ++++++
 alu/v0.1_16bit/alu.v           | 46 ++++++++++++++++++++++++++++++
 alu/v0.1_16bit/testbench_alu.v | 64 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 119 insertions(+)
 create mode 100644 alu/v0.1_16bit/Makefile
 create mode 100644 alu/v0.1_16bit/alu.v
 create mode 100644 alu/v0.1_16bit/testbench_alu.v

diff --git a/alu/v0.1_16bit/Makefile b/alu/v0.1_16bit/Makefile
new file mode 100644
index 0000000..0459ab3
--- /dev/null
+++ b/alu/v0.1_16bit/Makefile
@@ -0,0 +1,9 @@
+make:
+	iverilog -g2005-sv -o alu alu.v
+	iverilog -g2005-sv -o test_alu testbench_alu.v alu.v
+
+test:
+	vvp test_alu
+
+wave:
+	gtkwave test_alu.vcd
diff --git a/alu/v0.1_16bit/alu.v b/alu/v0.1_16bit/alu.v
new file mode 100644
index 0000000..05bf227
--- /dev/null
+++ b/alu/v0.1_16bit/alu.v
@@ -0,0 +1,46 @@
+module alu(
+    input [15:0]a,b,
+    input [2:0]alu_sel,
+    output [15:0]alu_out,
+    output carry_out
+);
+
+reg [7:0]alu_result;
+wire [8:0]tmp;
+
+assign alu_out=alu_result; //result from alu
+//???
+assign tmp = {1'b0,a}+{1'b0,b};
+
+
+always @(*) 
+begin
+    case (alu_sel)
+    4'b0000: //addition
+        alu_result = a+b;
+    4'b0001: //substraction
+        alu_result = a-b;
+    4'b0010: //multiplication
+        alu_result = ~a;
+    4'b0011: //division
+        alu_result = a<<b;
+    4'b0100: //logical shift left
+        alu_result = a>>b;
+    4'b0101: //logical shift right
+        alu_result = a&b;
+    4'b0110: //rotate right
+        alu_result = a|b;
+    4'b0111: //rotate left
+        begin 
+            if (a<b) alu_result = 16'd1;
+            else alu_result = 16'd0;
+        end
+    default: 
+        alu_result = a+b;
+    endcase
+end
+
+assign zero = (alu_result==16'd0) ? 1'b1: 1'b0;
+
+
+endmodule
\ No newline at end of file
diff --git a/alu/v0.1_16bit/testbench_alu.v b/alu/v0.1_16bit/testbench_alu.v
new file mode 100644
index 0000000..9902e5b
--- /dev/null
+++ b/alu/v0.1_16bit/testbench_alu.v
@@ -0,0 +1,64 @@
+`timescale 1ns/1ps
+
+module testbench_alu;
+
+reg [7:0]var_1=0;
+reg [7:0]var_2=0;
+reg [3:0]op_sel;
+reg carry;
+
+//wire  val;
+//wire  out;
+wire  [7:0]out;
+
+//assign val=data;
+alu uut (
+    .a(var_1),
+    .b(var_2),
+    .alu_sel(op_sel),
+    .alu_out(out),
+    .carry_out(carry)
+);
+
+
+initial begin
+    $display("addition");
+    $dumpfile("test_alu.vcd");
+    $dumpvars(0,testbench_alu);
+    var_1=0;
+    var_2=0;
+    op_sel=0;
+    #10 var_1=1;
+    var_2=0;
+
+    #10 var_1=0;
+    var_2=1;
+
+    #10 var_1=16;
+    var_2=16;
+
+    #10 var_1=64;
+    var_2=64;
+
+    $display("substraction");
+    $display("multiplication");
+    $display("division");
+    $display("logical shift left");
+    $display("logical shift right");
+    $display("rotate right");
+    $display("rotate left");
+    $display("and");
+    $display("or");
+    $display("xor");
+    $display("nor");
+    $display("nand");
+    $display("xnor");
+    $display("greater comparison");
+    $display("equal comparison");
+end
+
+initial begin
+    $monitor("At time %t d1=%h(%0d) d2=%h(%0d) op_sel=%0d out=%h(%0d)",$time,var_1,var_1,var_2,var_2,op_sel,out,out);
+end 
+
+endmodule
\ No newline at end of file
-- 
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