inter_pred_pipeline.v

a H.264/AVC Baseline Decoder

									begin
										if (xInt_org_unclip[1:0] == 2'b11)	// 4 preload cycles
											xInt_curr_offset <= (blk4x4_inter_preload_counter_m2[0] == 1'b1)? 5'b0:5'b0100;
										else
											xInt_curr_offset <= 0;
									end
								else
									begin
										if (xInt_org_unclip[1] == 1'b0)
											xInt_curr_offset <= 0;
										else
											xInt_curr_offset <= (blk4x4_inter_preload_counter_m2[0] == 1'b1)? 5'b0:5'b0100;
									end
							end
					end
			end
		else	//blk4x4_inter_preload_counter == 0 || blk4x4_inter_preload_counter == 1 
			xInt_curr_offset <= 5'b0; 
	
	//Derive unclipped x pos for each preload cycle
	wire [8:0] xInt_addr_unclip;
	assign xInt_addr_unclip = xInt_org_unclip + {{4{xInt_curr_offset[4]}},xInt_curr_offset};
	
	//x addr clipped:x address in pixels
	reg [7:0] xInt_addr;
	always @ (xInt_addr_unclip or IsInterLuma or IsInterChroma)
		if (xInt_addr_unclip[8] == 1'b1)	//negative
			xInt_addr <= 0;
		else if (IsInterLuma)
			xInt_addr <= (xInt_addr_unclip[7:0] > (`pic_width - 4))? 8'd172:xInt_addr_unclip[7:0];
		else if (IsInterChroma)
			xInt_addr <= (xInt_addr_unclip[7:0] > (`half_pic_width - 4))? 8'd84:xInt_addr_unclip[7:0];
		else
			xInt_addr <= 0;
			
	//yInt_p1:when loading from Xth line to (X-1)th line,yInt_p1 is set to 1'b1 at the last
	//loading cycle of current Xth line
	reg yInt_p1;
	always @ (IsInterLuma or mv_below8x8_curr or pos_FracL or xFracC or yFracC 
		or blk4x4_inter_preload_counter or blk4x4_inter_preload_counter_m2 or xInt_org_unclip[1:0] or xInt_org_unclip[1])
		if (blk4x4_inter_preload_counter != 6'd0 && blk4x4_inter_preload_counter != 6'd1)
			begin
				if (IsInterLuma)
					case (mv_below8x8_curr)
						1'b0:
						case (pos_FracL)
							`pos_f,`pos_q,`pos_i,`pos_k,`pos_j:
							yInt_p1 <= (blk4x4_inter_preload_counter_m2[1:0] == 2'b00)? 1'b1:1'b0;
							`pos_d,`pos_h,`pos_n:
							if (xInt_org_unclip[1:0] == 2'b00)
								yInt_p1 <= (blk4x4_inter_preload_counter_m2[0] == 1'b0)? 1'b1:1'b0;
							else
								case (blk4x4_inter_preload_counter_m2)
									6'd36,6'd33,6'd30,6'd27,6'd24,6'd21,6'd18,6'd15,6'd12,6'd9,6'd6,6'd3,6'd0:
									yInt_p1 <= 1'b1;
									default:yInt_p1 <= 1'b0;
								endcase
							`pos_a,`pos_b,`pos_c:
							yInt_p1 <= (blk4x4_inter_preload_counter_m2[1:0] == 2'b00)? 1'b1:1'b0;
							`pos_Int:
							if (xInt_org_unclip[1:0] == 2'b00)
								yInt_p1 <= (blk4x4_inter_preload_counter_m2[0] == 1'b0)? 1'b1:1'b0;
							else
								case (blk4x4_inter_preload_counter_m2)
									6'd21,6'd18,6'd15,6'd12,6'd9,6'd6,6'd3,6'd0:yInt_p1 <= 1'b1;
									default:									yInt_p1 <= 1'b0;
								endcase
							`pos_e,`pos_g,`pos_p,`pos_r:
							case (blk4x4_inter_preload_counter_m2)
								6'd45,6'd42,6'd3,6'd0:yInt_p1 <= 1'b1;
								6'd6,6'd10,6'd14,6'd18,6'd22,6'd26,6'd30,6'd34,6'd38:yInt_p1 <= 1'b1;
								default:yInt_p1 <= 1'b0;
							endcase
						endcase
						1'b1:		//block partition below 8x8
						case (pos_FracL)
							`pos_f,`pos_q,`pos_i,`pos_k,`pos_j:
							case (blk4x4_inter_preload_counter_m2)
								6'd24,6'd21,6'd18,6'd15,6'd12,6'd9,6'd6,6'd3,6'd0:yInt_p1 <= 1'b1;
								default:yInt_p1 <= 1'b0;
							endcase
							`pos_d,`pos_h,`pos_n:
							if (xInt_org_unclip[1:0] == 2'b00)
								yInt_p1 <= 1'b1;	
							else
								yInt_p1 <= (blk4x4_inter_preload_counter_m2[0] == 1'b0)? 1'b1:1'b0;
							`pos_a,`pos_b,`pos_c:
							case (blk4x4_inter_preload_counter_m2)
								5'd9,5'd6,5'd3,5'd0	:yInt_p1 <= 1'b1;
								default				:yInt_p1 <= 1'b0;
							endcase
							`pos_Int:
							if (xInt_org_unclip[1:0] == 2'b00)
								yInt_p1 <= 1'b1;
							else
								yInt_p1 <= (blk4x4_inter_preload_counter_m2[0] == 1'b0)? 1'b1:1'b0;
							`pos_e,`pos_g,`pos_p,`pos_r:
							case (blk4x4_inter_preload_counter_m2)
								6'd21,6'd19,6'd2,6'd0		:yInt_p1 <= 1'b1;
								6'd4,6'd7,6'd10,6'd13,6'd16	:yInt_p1 <= 1'b1;
								default						:yInt_p1 <= 1'b0;
							endcase
						endcase
					endcase
				else	//IsInterChroma
					case (mv_below8x8_curr)
						1'b0:
						if (xFracC == 0 && yFracC == 0)
							begin
								if (xInt_org_unclip[1:0] == 2'b00)
									yInt_p1 <= 1'b1;
								else
									yInt_p1 <= (blk4x4_inter_preload_counter_m2[0] == 1'b0)? 1'b1:1'b0;
							end
						else
							yInt_p1 <= (blk4x4_inter_preload_counter_m2[0] == 1'b0)? 1'b1:1'b0;
						1'b1:
						if (xFracC == 0 && yFracC == 0)
							begin
								if (xInt_org_unclip[1:0] != 2'b11)
									yInt_p1 <= 1'b1;
								else
									yInt_p1 <= (blk4x4_inter_preload_counter_m2[0] == 1'b0)? 1'b1:1'b0;
							end
						else
							begin
								if (xInt_org_unclip[1] == 1'b0)
									yInt_p1 <= 1'b1;
								else 
									yInt_p1 <= (blk4x4_inter_preload_counter_m2[0] == 1'b0)? 1'b1:1'b0;
							end
					endcase
			end
		else	// blk4x4_inter_preload_counter == 0 || blk4x4_inter_preload_counter == 1			
			yInt_p1 <= 1'b0; 
	
	//Derive unclipped y pos for each preload cycle
	reg [8:0] yInt_addr_unclip;
	always @ (posedge clk)
		if (reset_n == 1'b0)
			yInt_addr_unclip <= 0;
		else if ((IsInterLuma && (trigger_blk4x4_inter_pred && (mv_below8x8_curr ||
			(!mv_below8x8_curr && blk4x4_rec_counter[1:0] == 2'b00)))) ||
			(IsInterChroma && (!mv_below8x8_curr && trigger_blk4x4_inter_pred) ||
							   (mv_below8x8_curr && trigger_blk2x2_inter_pred)))
			begin
				if (IsInterLuma)	//Luma
					case (pos_FracL)
						`pos_a,`pos_b,`pos_c,`pos_Int:
						yInt_addr_unclip <= yInt_org_unclip;
						default:				//need -2 here
						yInt_addr_unclip <= yInt_org_unclip + 9'b111111110;
					endcase
				else			   //Chroma
					yInt_addr_unclip <= yInt_org_unclip;
			end
		else if (blk4x4_inter_preload_counter_m2 != 0 && yInt_p1 == 1'b1)
			yInt_addr_unclip <= yInt_addr_unclip + 1;
		
	//y addr clipped
	reg [7:0] yInt_addr;
	always @ (yInt_addr_unclip or IsInterLuma or IsInterChroma)
		if (yInt_addr_unclip[8] == 1'b1)	//negative
			yInt_addr <= 0;
		else if (IsInterLuma)
			yInt_addr <= (yInt_addr_unclip[7:0] > (`pic_height - 1))? 8'd143:yInt_addr_unclip[7:0];
		else if (IsInterChroma)
			yInt_addr <= (yInt_addr_unclip[7:0] > (`half_pic_height - 1))? 8'd71:yInt_addr_unclip[7:0];
		else
			yInt_addr <= 0;
		
	wire [12:0] offset_constant;
	wire [10:0] yInt_addr_x11;
	wire [12:0]	offset_yInt_addr;
	assign offset_constant = (IsInterLuma)? 0:((IsInterChroma)? ((blk4x4_rec_counter < 5'd20)? 13'd6336:13'd7920):0); 
	assign yInt_addr_x11 = {yInt_addr,3'b0} + {2'b0,yInt_addr,1'b0} + {3'b0,yInt_addr};
	assign offset_yInt_addr = (IsInterLuma)? {yInt_addr_x11,2'b0}:{1'b0,yInt_addr_x11,1'b0};
	assign ref_frame_RAM_rd_addr = (offset_constant + {8'b0,xInt_addr[7:2]}) + {1'b0,offset_yInt_addr};
	
	//----------------------------------------------------------------------------------------
	//Inter prediction output control: from LPE or from CPE
	//----------------------------------------------------------------------------------------
	always @ (IsInterLuma or IsInterChroma or Is_InterChromaCopy 
		or blk4x4_inter_calculate_counter or pos_FracL
		or Inter_pix_copy0 or Inter_pix_copy1 or Inter_pix_copy2 or Inter_pix_copy3
		or LPE0_out or LPE1_out or LPE2_out or LPE3_out
		or CPE0_out or CPE1_out or CPE2_out or CPE3_out) 
		if (IsInterLuma && blk4x4_inter_calculate_counter != 0)
			begin
				Inter_blk4x4_pred_output_valid <= 2'b01;
				case (pos_FracL)
					`pos_Int:
					begin
						Inter_pred_out0 <= Inter_pix_copy0;Inter_pred_out1 <= Inter_pix_copy1;
						Inter_pred_out2 <= Inter_pix_copy2;Inter_pred_out3 <= Inter_pix_copy3;
					end
					`pos_i,`pos_k:
					if (blk4x4_inter_calculate_counter == 4'd7 || blk4x4_inter_calculate_counter == 4'd5 || 
						blk4x4_inter_calculate_counter == 4'd3 || blk4x4_inter_calculate_counter == 4'd1)
						begin
							Inter_pred_out0 <= LPE0_out;Inter_pred_out1 <= LPE1_out;
							Inter_pred_out2 <= LPE2_out;Inter_pred_out3 <= LPE3_out;
						end
					else
						begin
							Inter_pred_out0 <= 0;Inter_pred_out1 <= 0;Inter_pred_out2 <= 0;Inter_pred_out3 <= 0;
						end
					default:
					if (blk4x4_inter_calculate_counter == 4'd4 || blk4x4_inter_calculate_counter == 4'd3 || 
						blk4x4_inter_calculate_counter == 4'd2 || blk4x4_inter_calculate_counter == 4'd1)
						begin
							Inter_pred_out0 <= LPE0_out;Inter_pred_out1 <= LPE1_out;
							Inter_pred_out2 <= LPE2_out;Inter_pred_out3 <= LPE3_out;
						end
					else
						begin
							Inter_pred_out0 <= 0;Inter_pred_out1 <= 0;Inter_pred_out2 <= 0;Inter_pred_out3 <= 0;
						end
				endcase
			end
		else if (IsInterChroma && blk4x4_inter_calculate_counter != 0)
			begin
				Inter_pred_out0 <= (Is_InterChromaCopy)? Inter_pix_copy0:CPE0_out;
				Inter_pred_out1 <= (Is_InterChromaCopy)? Inter_pix_copy1:CPE1_out;
				Inter_pred_out2 <= (Is_InterChromaCopy)? Inter_pix_copy2:CPE2_out;
				Inter_pred_out3 <= (Is_InterChromaCopy)? Inter_pix_copy3:CPE3_out;
				Inter_blk4x4_pred_output_valid <= 2'b10;
			end
		else
			begin
				Inter_pred_out0 <= 0;Inter_pred_out1 <= 0;Inter_pred_out2 <= 0;Inter_pred_out3 <= 0;
				Inter_blk4x4_pred_output_valid <= 2'b00;
			end
endmodule