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Add JAL/JALR support to the ALU

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This commit is contained in:
Graham Edgecombe 2017-12-01 22:58:10 +00:00
parent 37d703c83e
commit 5884a437b8
3 changed files with 7 additions and 1 deletions
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1
rv32_alu.sv
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@ -46,6 +46,7 @@ module rv32_alu (
RV32_ALU_OP_SRL_SRA: result_out <= srl_sra;
RV32_ALU_OP_SLT: result_out <= {31'b0, lt};
RV32_ALU_OP_SLTU: result_out <= {31'b0, ltu};
RV32_ALU_OP_SRC1P4: result_out <= src1 + 4;
RV32_ALU_OP_SRC2: result_out <= src2;
default: result_out <= 32'bx;
endcase

3
rv32_alu_ops.sv
View file

@ -6,7 +6,8 @@ localparam RV32_ALU_OP_SLL = 4'b0100;
localparam RV32_ALU_OP_SRL_SRA = 4'b0101;
localparam RV32_ALU_OP_SLT = 4'b0110;
localparam RV32_ALU_OP_SLTU = 4'b0111;
localparam RV32_ALU_OP_SRC2 = 4'b1000;
localparam RV32_ALU_OP_SRC1P4 = 4'b1000;
localparam RV32_ALU_OP_SRC2 = 4'b1001;
localparam RV32_ALU_SRC1_REG = 1'b0;
localparam RV32_ALU_SRC1_PC = 1'b1;

4
rv32_decode.sv
View file

@ -81,11 +81,15 @@ module rv32_decode (
{RV32_OPCODE_JAL, RV32_FUNCT3_ANY, RV32_FUNCT7_ANY}: begin
/* JAL */
valid_out <= 1;
alu_op_out <= RV32_ALU_OP_SRC1P4;
alu_src1_out <= RV32_ALU_SRC1_PC;
imm_out <= imm_j;
end
{RV32_OPCODE_JALR, RV32_FUNCT3_ZERO, RV32_FUNCT7_ANY}: begin
/* JALR */
valid_out <= 1;
alu_op_out <= RV32_ALU_OP_SRC1P4;
alu_src1_out <= RV32_ALU_SRC1_PC;
imm_out <= imm_i;
end
{RV32_OPCODE_BRANCH, RV32_FUNCT3_BRANCH_BEQ, RV32_FUNCT7_ANY}: begin