mirror of https://github.com/YosysHQ/yosys.git
80 lines
2.0 KiB
Verilog
80 lines
2.0 KiB
Verilog
|
module alu(
|
||
|
|
input clk,
|
||
|
|
input [7:0] A,
|
||
|
|
input [7:0] B,
|
||
|
|
input [3:0] operation,
|
||
|
|
output reg [7:0] result,
|
||
|
|
output reg CF,
|
||
|
|
output reg ZF,
|
||
|
|
output reg SF
|
||
|
|
);
|
||
|
|
|
||
|
|
localparam ALU_OP_ADD /* verilator public_flat */ = 4'b0000;
|
||
|
|
localparam ALU_OP_SUB /* verilator public_flat */ = 4'b0001;
|
||
|
|
localparam ALU_OP_ADC /* verilator public_flat */ = 4'b0010;
|
||
|
|
localparam ALU_OP_SBC /* verilator public_flat */ = 4'b0011;
|
||
|
|
|
||
|
|
localparam ALU_OP_AND /* verilator public_flat */ = 4'b0100;
|
||
|
|
localparam ALU_OP_OR /* verilator public_flat */ = 4'b0101;
|
||
|
|
localparam ALU_OP_NOT /* verilator public_flat */ = 4'b0110;
|
||
|
|
localparam ALU_OP_XOR /* verilator public_flat */ = 4'b0111;
|
||
|
|
|
||
|
|
localparam ALU_OP_SHL /* verilator public_flat */ = 4'b1000;
|
||
|
|
localparam ALU_OP_SHR /* verilator public_flat */ = 4'b1001;
|
||
|
|
localparam ALU_OP_SAL /* verilator public_flat */ = 4'b1010;
|
||
|
|
localparam ALU_OP_SAR /* verilator public_flat */ = 4'b1011;
|
||
|
|
|
||
|
|
localparam ALU_OP_ROL /* verilator public_flat */ = 4'b1100;
|
||
|
|
localparam ALU_OP_ROR /* verilator public_flat */ = 4'b1101;
|
||
|
|
localparam ALU_OP_RCL /* verilator public_flat */ = 4'b1110;
|
||
|
|
localparam ALU_OP_RCR /* verilator public_flat */ = 4'b1111;
|
||
|
|
|
||
|
|
reg [8:0] tmp;
|
||
|
|
|
||
|
|
always @(posedge clk)
|
||
|
|
begin
|
||
|
|
case (operation)
|
||
|
|
ALU_OP_ADD :
|
||
|
|
tmp = A + B;
|
||
|
|
ALU_OP_SUB :
|
||
|
|
tmp = A - B;
|
||
|
|
ALU_OP_ADC :
|
||
|
|
tmp = A + B + { 7'b0000000, CF };
|
||
|
|
ALU_OP_SBC :
|
||
|
|
tmp = A - B - { 7'b0000000, CF };
|
||
|
|
ALU_OP_AND :
|
||
|
|
tmp = {1'b0, A & B };
|
||
|
|
ALU_OP_OR :
|
||
|
|
tmp = {1'b0, A | B };
|
||
|
|
ALU_OP_NOT :
|
||
|
|
tmp = {1'b0, ~B };
|
||
|
|
ALU_OP_XOR :
|
||
|
|
tmp = {1'b0, A ^ B};
|
||
|
|
ALU_OP_SHL :
|
||
|
|
tmp = { A[7], A[6:0], 1'b0};
|
||
|
|
ALU_OP_SHR :
|
||
|
|
tmp = { A[0], 1'b0, A[7:1]};
|
||
|
|
ALU_OP_SAL :
|
||
|
|
// Same as SHL
|
||
|
|
tmp = { A[7], A[6:0], 1'b0};
|
||
|
|
ALU_OP_SAR :
|
||
|
|
tmp = { A[0], A[7], A[7:1]};
|
||
|
|
ALU_OP_ROL :
|
||
|
|
tmp = { A[7], A[6:0], A[7]};
|
||
|
|
ALU_OP_ROR :
|
||
|
|
tmp = { A[0], A[0], A[7:1]};
|
||
|
|
ALU_OP_RCL :
|
||
|
|
tmp = { A[7], A[6:0], CF};
|
||
|
|
ALU_OP_RCR :
|
||
|
|
tmp = { A[0], CF, A[7:1]};
|
||
|
|
endcase
|
||
|
|
|
||
|
|
CF <= tmp[8];
|
||
|
|
ZF <= tmp[7:0] == 0;
|
||
|
|
SF <= tmp[7];
|
||
|
|
|
||
|
|
result <= tmp[7:0];
|
||
|
|
end
|
||
|
|
endmodule
|
||
|
|
|