diff --git a/FINAL/RISCCore.v b/FINAL/RISCCore.v index 593400b..4d4580f 100644 --- a/FINAL/RISCCore.v +++ b/FINAL/RISCCore.v @@ -120,7 +120,9 @@ module RISCCore ( wire isJALR = (opcode == 7'b1100111) && (funct3 == 3'b000); //Mem address calculation - wire [31:0] mem_addr = (is_mem_op) ? alu_result : 32'b0; + /*wire [31:0] mem_addr = (is_mem_op) ? alu_result : 32'b0; + Using direct */ + wire [31:0] mem_addr = rs1_val + (isSType ? Simm : Iimm); //Mem address logic //For simplicity we only implement all loads as word loads (lw) @@ -153,40 +155,52 @@ module RISCCore ( end //Store operations -always @(*) begin +always @(posedge clk) begin if (!rst && is_store && (word_addr < 32) && (mem_addr[1:0] == 2'b00)) begin + case (funct3) - 3'b000: begin //SB: store byte 0 - dmem[word_addr][7:0] = rs2_val[7:0]; - end - 3'b001: begin //SH: store halfword - dmem[word_addr][15:0] = rs2_val[15:0]; - end - 3'b010: begin //SW: store word - dmem[word_addr] = rs2_val; - end + 3'b000: dmem[word_addr] <= {dmem[word_addr][31:8], rs2_val[7:0]}; // SB + 3'b001: dmem[word_addr] <= {dmem[word_addr][31:16], rs2_val[15:0]}; // SH + 3'b010: dmem[word_addr] <= rs2_val; // SW endcase + // The $display can be simplified now as well $display("MEM Write: word_addr=%h, data=%h", word_addr, rs2_val); end end // ALU operations //sltu and slt - wire [31:0] sltu_rslt = {31'b0, (rs1_val < rs2_val)}; - wire [31:0] signed_slt = (rs1_val[31] && !rs2_val[31]) ? 1'b1 : - (!rs1_val[31] && rs2_val[31]) ? 1'b0 : - (rs1_val < rs2_val); - wire [31:0] slt_rslt = {31'b0, signed_slt}; - wire [31:0] slti_rslt = ((rs1_val[31] == Iimm[31]) ? sltu_rslt : {31'b0, rs1_val[31]}); + // For signed operations, cast the inputs to 'signed'. + // Verilog will then use 2's complement arithmetic automatically. + wire signed [31:0] signed_rs1_val = rs1_val; + wire signed [31:0] signed_Iimm = Iimm; - wire [63:0] SErs1_val = {{32{rs1_val[31]}}, (rs1_val < rs2_val)}; + // SLTU: Set if Less Than (Unsigned) + // Compares rs1_val and rs2_val as unsigned integers. + wire [31:0] sltu_rslt = (rs1_val < rs2_val) ? 32'd1 : 32'd0; - wire [63:0] sra_rslt = {SErs1_val >> rs2_val[4:0]}; - wire [63:0] srai_rslt = {SErs1_val >> Iimm[4:0]}; - wire [31:0] sltiu_rslt = {31'b0, (rs1_val < Iimm)}; + // SLT: Set if Less Than (Signed) + // Compares rs1_val and rs2_val as signed integers. + wire [31:0] slt_rslt = (signed_rs1_val < $signed(rs2_val)) ? 32'd1 : 32'd0; + + // SLTIU: Set if Less Than Immediate (Unsigned) + // Compares rs1_val (unsigned) with the sign-extended immediate (unsigned). + wire [31:0] sltiu_rslt = (rs1_val < Iimm) ? 32'd1 : 32'd0; + + // SLTI: Set if Less Than Immediate (Signed) + // Compares rs1_val and the immediate as signed integers. + wire [31:0] slti_rslt = (signed_rs1_val < signed_Iimm) ? 32'd1 : 32'd0; + + // SRA: Shift Right Arithmetic + // Shifts signed_rs1_val right by the amount in rs2_val[4:0]. + // The '>>>' operator performs an arithmetic shift, preserving the sign bit. + wire [31:0] sra_rslt = signed_rs1_val >>> rs2_val[4:0]; + + // SRAI: Shift Right Arithmetic Immediate + // Shifts signed_rs1_val right by the immediate amount in Iimm[4:0]. + wire [31:0] srai_rslt = signed_rs1_val >>> Iimm[4:0]; - wire [31:0] alu_result = (is_mem_op) ? (rs1_val + Iimm) : // Mem address computation - (isADDI) ? (rs1_val + Iimm) : + wire [31:0] alu_result = (isADDI) ? (rs1_val + Iimm) : (isADD) ? (rs1_val + rs2_val) : (isSLT) ? slt_rslt : (isSLTU) ? sltu_rslt : @@ -203,11 +217,11 @@ end (isSLL) ? (rs1_val << rs2_val[4:0]) : (isSRL) ? (rs1_val >> rs2_val[4:0]) : (isSLTIU) ? (sltiu_rslt) : - (isLUI) ? ({Iimm[31:12], 12'b0}) : - (isAUIPC) ? (pc + Iimm) : + (isLUI) ? Uimm : + (isAUIPC) ? (pc + Uimm) : (isJAL || isJALR) ? (pc + 32'd4) : - (isSRA) ? (sra_rslt[31:0]) : - (isSRAI) ? (srai_rslt[31:0]) : + (isSRA) ? sra_rslt : + (isSRAI) ? srai_rslt : 32'b0; @@ -226,10 +240,11 @@ end // Next PC calculation - FIXED: using wire for continuous assignment wire [31:0] branch_target = pc + Bimm; wire [31:0] next_pc_base = pc + 32'h4; - wire [31:0] jalr_tgt_pc = rs1_val + Iimm; + wire [31:0] jalr_tgt_pc = (rs1_val + Iimm) & 32'hFFFFFFFE; + wire [31:0] jal_target = pc + Jimm; assign next_pc = branch_taken ? branch_target : - isJAL ? branch_target : + isJAL ? jal_target : isJALR ? jalr_tgt_pc : next_pc_base;