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-rw-r--r--rtl/alu.sv47
1 files changed, 18 insertions, 29 deletions
diff --git a/rtl/alu.sv b/rtl/alu.sv
index 30645c1..2966135 100644
--- a/rtl/alu.sv
+++ b/rtl/alu.sv
@@ -1,6 +1,8 @@
-module alu
- import montreal_pkg::*;
-#(
+/* SPDX-License-Identifier: CERN-OHL-P-2.0 */
+
+`include "types.svh"
+
+module alu #(
parameter int unsigned XLEN = config_pkg::XLEN,
parameter int unsigned SLICE_WIDTH = config_pkg::SLICE_WIDTH,
@@ -27,48 +29,35 @@ module alu
/* Carry signals. */
logic carry, carry_d, carry_q;
- /* Adder width is SLICE_WIDTH + 1 to account for carry-out. */
- logic [SLICE_WIDTH:0] adder_a, adder_b, adder_result;
-
- /* For the first slice, carry-in must be driven to zero for addition
- * and one for subtraction or comparisons. All other slices use the
+ /* For the first slice, carry-in must be driven to zero for addition
+ * and one for subtraction or comparisons. All other slices use the
* carry-out from the previous slice */
+ assign carry = (count_i == '0) ? negate_b : carry_q;
- assign carry = (count_i == '0) ? negate_b : carry_q;
+ /* Adder width is SLICE_WIDTH + 1 to account for carry-out. */
+ logic [SLICE_WIDTH:0] adder_a, adder_b, adder_result;
- /* ADD, SUB, SLT, SLTU use the same adder to computer their results*/
-
assign adder_a = {1'b0, a_i};
assign adder_b = {1'b0, (b_i ^ {SLICE_WIDTH{negate_b}})};
+
+ /* ADD, SUB, SLT, SLTU use the same adder to computer their results*/
assign adder_result = adder_a + adder_b + (SLICE_WIDTH + 1)'(carry);
+
assign carry_o = adder_result[SLICE_WIDTH];
assign carry_d = carry_o;
/* Combinational arithmetic/logic core. */
always_comb begin : alu_core
- result_o = '0;
-
unique casez (alu_op_i[2:0])
/* ADD, SUB, SLT, SLTU. */
- 3'b0??: begin
- result_o = adder_result[SLICE_WIDTH-1:0];
- end
+ 3'b0??: result_o = adder_result[SLICE_WIDTH-1:0];
/* XOR. */
- 3'b100: begin
- result_o = a_i ^ b_i;
- carry_d = 0;
- end
+ 3'b100: result_o = a_i ^ b_i;
/* OR. */
- 3'b110: begin
- result_o = a_i | b_i;
- carry_d = 0;
- end
+ 3'b110: result_o = a_i | b_i;
/* AND. */
- 3'b111: begin
- result_o = a_i & b_i;
- carry_d = 0;
- end
- default: begin end
+ 3'b111: result_o = a_i & b_i;
+ default: result_o = '0;
endcase
end : alu_core