datapadunit.v

hmac的verilog代码, 通过控制字选择进行sha1运算或hmac运算

			begin
				if (hashover)
					nextstate = digestready;
				else 
					nextstate = waitmd2;
			end
		digestready:
			begin
				resultready = 1;
				nextstate = idle;
			end
		lengtherror:
			begin
				error = 1;
				if (en && !wr && (addr == 2) && lenerror)
					nextstate = idle;
				else
					nextstate = lengtherror;
			end
	endcase		
end

//receive the key and process the key
always @(posedge clk)
	begin
		if (reset)
			begin
				keyreg <= 0;	
				keyreadyreg <= 0;
			end
		else if (currentstate == rxkey)
			begin
				case (keycnt)
					0: keyreg[159:128] <= datatmp;
					1: keyreg[127:96]  <= datatmp;
					2: keyreg[95:64]   <= datatmp;
					3: keyreg[63:32]   <= datatmp;
					4: keyreg[31:0]    <= datatmp;
				endcase
			end
		else if (currentstate == hmackeyready)
			keyreadyreg <= 1;
		else
			begin
				keyreg <= keyreg;
				keyreadyreg <= keyreadyreg;
			end
	end

//receive the datalength and comput the whole length automatically
always @(posedge clk)
	begin
		if (reset)
			begin
				datalength <= 0;
			end
		else if ((currentstate == rxlength) && !padflg)
			begin
				datalength[63:9] <= datalength[63:9] + 1;
			end
		else if ((currentstate == rxlength) && padflg && !modsel)
			begin
				datalength[8:0] <= datalength[8:0] + datatmp[8:0];
			end
		else if ((currentstate == rxlength) && padflg && modsel)
			begin
				datalength[8:0] <= datalength[8:0] + datatmp[8:0];
				datalength[63:9] <= datalength[63:9] + 1;
			end
		else if (digestreadyreg && padflg)
			datalength <= 0;
		else
			begin
				datalength <= datalength;
			end
	end
	
//receive data and pad data
always @(posedge clk)
	begin
		if (reset)
			begin
				paddata <= 0;
				procsel <= 0;
			end
		else
			begin
				case (currentstate)
					idle,rxkey: 
							begin
								paddata <= paddata;
								procsel <= 0;
							end
					sendikey:
						begin
							paddata[511:352] <= keyreg ^ {20{ipad}};
							paddata[351:0]   <= {44{ipad}};
							procsel <=1;
						end
					waitiv1: paddata <= paddata;
					sendokey:
						begin
							paddata[511:352] <= keyreg ^ {20{opad}};
							paddata[351:0]   <= {44{opad}};
							procsel <=2;
						end
					waitiv2:
						begin
							procsel <= 2;
						end
					hmackeyready,rxlength: paddata <= paddata;
					rxdata:
						case (datacnt)
							0:  paddata[511:480] <= datatmp;
							1:  paddata[479:448] <= datatmp;
							2:  paddata[447:416] <= datatmp;
							3:  paddata[415:384] <= datatmp;
							4:  paddata[383:352] <= datatmp;
							5:  paddata[351:320] <= datatmp;
							6:  paddata[319:288] <= datatmp;
							7:  paddata[287:256] <= datatmp;
							8:  paddata[255:224] <= datatmp;
							9:  paddata[223:192] <= datatmp;
							10: paddata[191:160] <= datatmp;
							11: paddata[159:128] <= datatmp;
							12: paddata[127:096] <= datatmp;
							13: paddata[095:064] <= datatmp;
							14: paddata[063:032] <= datatmp;
							15: paddata[031:000] <= datatmp;
						endcase
					datapad:
						begin
							case (datalength[8:5])
								0: 
									begin
										case (datalength[4:3])
													0: paddata[511:480] <= 32'h80000000;
													1: paddata[511:480] <= paddata[511:480] + 32'h00800000;
													2: paddata[511:480] <= paddata[511:480] + 32'h00008000;
													3: paddata[511:480] <= paddata[511:480] + 32'h00000080;
										endcase
										paddata[479:0] <= 0;	
											
									end
								1: 
									begin
										case (datalength[4:3])
											0: paddata[479:448] <= 32'h80000000;
											1: paddata[479:448] <= paddata[479:448] + 32'h00800000;
											2: paddata[479:448] <= paddata[479:448] + 32'h00008000;
											3: paddata[479:448] <= paddata[479:448] + 32'h00000080;
										endcase
										paddata[447:0] <= 0;	
									end
								2: 
									begin
										case (datalength[4:3])
											0: paddata[447:416] <= 32'h80000000;
											1: paddata[447:416] <= paddata[447:416] + 32'h00800000;
											2: paddata[447:416] <= paddata[447:416] + 32'h00008000;
											3: paddata[447:416] <= paddata[447:416] + 32'h00000080;
										endcase
										paddata[415:0] <= 0;
									end
								3: 
									begin
										case (datalength[4:3])
											0: paddata[415:384] <= 32'h80000000;
											1: paddata[415:384] <= paddata[415:384] + 32'h00800000;
											2: paddata[415:384] <= paddata[415:384] + 32'h00008000;
											3: paddata[415:384] <= paddata[415:384] + 32'h00000080;
										endcase
										paddata[383:0] <= 0;
									end
								4: 
									begin
										case (datalength[4:3])
											0: paddata[383:352] <= 32'h80000000;
											1: paddata[383:352] <= paddata[383:352] + 32'h00800000;
											2: paddata[383:352] <= paddata[383:352] + 32'h00008000;
											3: paddata[383:352] <= paddata[383:352] + 32'h00000080;
										endcase
										paddata[351:0] <= 0;
									end
								5: 
									begin
										case (datalength[4:3])
											0: paddata[351:320] <= 32'h80000000;
											1: paddata[351:320] <= paddata[351:320] + 32'h00800000;
											2: paddata[351:320] <= paddata[351:320] + 32'h00008000;
											3: paddata[351:320] <= paddata[351:320] + 32'h00000080;
										endcase
										paddata[319:0] <= 0;
									end
								6: 
									begin
										case (datalength[4:3])
											0: paddata[319:288] <= 32'h80000000;
											1: paddata[319:288] <= paddata[319:288] + 32'h00800000;
											2: paddata[319:288] <= paddata[319:288] + 32'h00008000;
											3: paddata[319:288] <= paddata[319:288] + 32'h00000080;
										endcase
										paddata[287:0] <= 0;
									end
								7: 
									begin
										case (datalength[4:3])
											0: paddata[287:256] <= 32'h80000000;
											1: paddata[287:256] <= paddata[287:256] + 32'h00800000;
											2: paddata[287:256] <= paddata[287:256] + 32'h00008000;
											3: paddata[287:256] <= paddata[287:256] + 32'h00000080;
										endcase
										paddata[255:0] <= 0;
									end
								8: 
									begin
										case (datalength[4:3])
											0: paddata[255:224] <= 32'h80000000;
											1: paddata[255:224] <= paddata[255:224] + 32'h00800000;
											2: paddata[255:224] <= paddata[255:224] + 32'h00008000;
											3: paddata[255:224] <= paddata[255:224] + 32'h00000080;
										endcase
										paddata[223:0] <= 0;
									end
								9: 
									begin
										case (datalength[4:3])
											0: paddata[223:192] <= 32'h80000000;
											1: paddata[223:192] <= paddata[223:192] + 32'h00800000;
											2: paddata[223:192] <= paddata[223:192] + 32'h00008000;
											3: paddata[223:192] <= paddata[223:192] + 32'h00000080;
										endcase
										paddata[191:0] <= 0;
									end
								10: 
									begin
										case (datalength[4:3])
											0: paddata[191:160] <= 32'h80000000;
											1: paddata[191:160] <= paddata[191:160] + 32'h00800000;
											2: paddata[191:160] <= paddata[191:160] + 32'h00008000;
											3: paddata[191:160] <= paddata[191:160] + 32'h00000080;
										endcase
										paddata[159:0] <= 0;
									end
								11: 
									begin
										case (datalength[4:3])
											0: paddata[159:128] <= 32'h80000000;
											1: paddata[159:128] <= paddata[159:128] + 32'h00800000;
											2: paddata[159:128] <= paddata[159:128] + 32'h00008000;
											3: paddata[159:128] <= paddata[159:128] + 32'h00000080;
										endcase
										paddata[127:0] <= 0;
									end
								12: 
									begin
										case (datalength[4:3])
											0: paddata[127:096] <= 32'h80000000;
											1: paddata[127:096] <= paddata[127:096] + 32'h00800000;
											2: paddata[127:096] <= paddata[127:096] + 32'h00008000;
											3: paddata[127:096] <= paddata[127:096] + 32'h00000080;
										endcase
										paddata[95:0] <= 0;
									end
								13: 
									begin
										case (datalength[4:3])
											0: paddata[095:064] <= 32'h80000000;
											1: paddata[095:064] <= paddata[095:064] + 32'h00800000;
											2: paddata[095:064] <= paddata[095:064] + 32'h00008000;
											3: paddata[095:064] <= paddata[095:064] + 32'h00000080;
										endcase
										paddata[63:0] <= 0;
									end
								14: 
									begin
										case (datalength[4:3])
											0: paddata[063:032] <= 32'h80000000;
											1: paddata[063:032] <= paddata[063:032] + 32'h00800000;
											2: paddata[063:032] <= paddata[063:032] + 32'h00008000;
											3: paddata[063:032] <= paddata[063:032] + 32'h00000080;
										endcase
										paddata[031:000] <= 0;
									end
								15: 
									begin
										case (datalength[4:3])
											0: paddata[031:000] <= 32'h80000000;
											1: paddata[031:000] <= paddata[031:000] + 32'h00800000;
											2: paddata[031:000] <= paddata[031:000] + 32'h00008000;
											3: paddata[031:000] <= paddata[031:000] + 32'h00000080;
										endcase
									end
							endcase
						end
						lengthpad:
							begin
								paddata[63:0] <= datalength;
							end
						senddata:
							begin
								paddata <= paddata;
							end
						expad:
							begin
								if (datalength[8:3]==0)
									begin
										paddata[511] <= 1;
										paddata[510:64] <= 0;
										paddata[63:0] <= datalength;
									end
								else
									begin
										paddata[511:64] <= 0;
										paddata[63:0] <= datalength;
									end
							end
						sendmd1:
							begin
								paddata[511:352] <= md1in;
								paddata[351] <=1;
								paddata[350:64] <=0;
								paddata[63:0] <=32'h000002a0;
								procsel <= 3;
							end
						//receive the digest from hashunit, and send it to the wtprounit
						//waitmd2://this state may be reduced
						//digestready://set the digestready flag in status reg
						//lengtherror://set the lengtherror flag in status reg
						//hmackeyready://set the hmackeyready flag in status reg
						waitmd2:
							begin
								procsel <= 3;
								paddata <= paddata;
							end
						digestready,lengtherror,hmackeyready: paddata <= paddata;
				endcase
			end
	end
endmodule