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alu_basic/alu_basic.v

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+/*
+    Basic ALU 16bit
+
+    inputs: opcode, a, b
+    outputs: result, zero, carry, negative
+
+    opcode[3:0]   |     Operación
+    -------------------------------
+            0x0   | 	ADD
+            0x1   | 	SUB
+            0x2   | 	MUL
+            0x3   | 	DIV
+            0x4   | 	AND
+            0x5   | 	OR
+            0x6   | 	NOT
+            0x7   | 	NAND
+            0x8   | 	NOR
+            0x9   | 	XOR
+            0xA   | 	XNOR
+            0xB   | 	NEG
+*/
+
+module basic_alu (
+    input [3:0] opcode,
+    input [15:0] a,
+    input [15:0] b,
+    output reg [15:0] result,
+    output zero,
+    output reg carry,
+    output negative
+);
+
+    always @(*) begin
+        carry = 0;
+
+        case (opcode)
+            4'h0: {carry, result} = a + b;      // ADD
+            4'h1: {carry, result} = a - b;      // SUB
+            4'h2: result = a * b;               // MUL
+            4'h3: result = a / b;               // DIV
+            4'h4: result = a & b;               // AND
+            4'h5: result = a | b;               // OR
+            4'h6: result = ~a;                  // NOT
+            4'h7: result = ~(a & b);            // NAND
+            4'h8: result = ~(a | b);            // NOR
+            4'h9: result = a ^ b;               // XOR
+            4'hA: result = ~(a ^ b);            // XNOR
+            4'hB: result = ~a + 1;              // NEG
+            default: result = 0;
+        endcase
+    end
+
+    assign zero = result == 0;
+    assign negative = result[15];
+
+endmodule