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/*******************************************************************************************/
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/** **/
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/** COPYRIGHT (C) 2011, SYSTEMYDE INTERNATIONAL CORPORATION, ALL RIGHTS RESERVED **/
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/** **/
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/** alu b input multiplexer module Rev 0.0 07/24/2011 **/
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/** **/
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/*******************************************************************************************/
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module alubmux (addb_in, alub_in, alub_reg, af_reg_out, bc_reg_out, de_reg_out, din0_reg,
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din1_reg, hl_reg_out, ix_reg, iy_reg, pc_reg, sp_reg, tmp_reg);
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input [7:0] din0_reg; /* data input 0 register */
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input [7:0] din1_reg; /* data input 1 register */
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input [15:0] af_reg_out; /* af register output */
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input [15:0] bc_reg_out; /* bc register output */
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input [15:0] de_reg_out; /* de register output */
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input [15:0] hl_reg_out; /* hl register output */
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input [15:0] ix_reg; /* ix register output */
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input [15:0] iy_reg; /* iy register output */
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input [15:0] pc_reg; /* pc register output */
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input [15:0] sp_reg; /* sp register output */
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input [15:0] tmp_reg; /* temporary register output */
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input [`ALUB_IDX:0] alub_reg; /* pipelined alu input b mux control */
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output [15:0] addb_in; /* address alu b input bus */
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output [15:0] alub_in; /* alu b input bus */
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/*****************************************************************************************/
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/* */
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/* signal declarations */
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/* */
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/*****************************************************************************************/
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wire [15:0] alub_in;
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reg [15:0] alub_mux;
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reg [15:0] alub_mux_1, alub_mux_2, alub_mux_3, alub_mux_4, alub_mux_5;
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reg [15:0] alub_mux_6, alub_mux_7, alub_mux_8, alub_mux_9, alub_mux_10, alub_mux_11;
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wire [15:0] addb_in;
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wire [15:0] addb_mux_2, addb_mux_3, addb_mux_4, addb_mux_5, addb_mux_6, addb_mux_7;
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wire [15:0] addb_mux_8, addb_mux_9, addb_mux_10, addb_mux_12;
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/*****************************************************************************************/
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/* */
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/* alu input b select */
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/* */
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/*****************************************************************************************/
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always @ (alub_reg or af_reg_out or bc_reg_out or de_reg_out or hl_reg_out or ix_reg or
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iy_reg or sp_reg or din1_reg or din0_reg or tmp_reg or pc_reg) begin
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alub_mux_1 = 32'h0;
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alub_mux_2 = 32'h0;
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alub_mux_3 = 32'h0;
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alub_mux_4 = 32'h0;
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alub_mux_5 = 32'h0;
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alub_mux_6 = 32'h0;
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alub_mux_7 = 32'h0;
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alub_mux_8 = 32'h0;
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alub_mux_9 = 32'h0;
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alub_mux_10 = 32'h0;
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alub_mux_11 = 32'h0;
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if (alub_reg[`AB_AF]) alub_mux_1 = af_reg_out;
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if (alub_reg[`AB_BC]) alub_mux_2 = bc_reg_out;
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if (alub_reg[`AB_DE]) alub_mux_3 = de_reg_out;
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if (alub_reg[`AB_HL]) alub_mux_4 = hl_reg_out;
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if (alub_reg[`AB_IX]) alub_mux_5 = ix_reg;
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if (alub_reg[`AB_IY]) alub_mux_6 = iy_reg;
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if (alub_reg[`AB_SP]) alub_mux_7 = sp_reg;
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if (alub_reg[`AB_DIN]) alub_mux_8 = {din1_reg, din0_reg};
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if (alub_reg[`AB_IO]) alub_mux_9 = {af_reg_out[15:8], din0_reg};
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if (alub_reg[`AB_TMP]) alub_mux_10 = tmp_reg;
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if (alub_reg[`AB_PC]) alub_mux_11 = pc_reg;
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end
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always @ (alub_mux_1 or alub_mux_2 or alub_mux_3 or alub_mux_4 or alub_mux_5 or
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alub_mux_6 or alub_mux_7 or alub_mux_8 or alub_mux_9 or alub_mux_10 or
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alub_mux_11) begin
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alub_mux = alub_mux_1 | alub_mux_2 | alub_mux_3 | alub_mux_4 | alub_mux_5 |
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alub_mux_6 | alub_mux_7 | alub_mux_8 | alub_mux_9 | alub_mux_10 | alub_mux_11;
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end
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assign alub_in = (alub_reg[`AB_SHR]) ? {alub_mux[15:8], alub_mux[15:8]} : alub_mux;
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/*****************************************************************************************/
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/* */
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/* address alu input b select */
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/* */
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/*****************************************************************************************/
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assign addb_mux_2 = (alub_reg[`AB_BC]) ? bc_reg_out : 16'h0;
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assign addb_mux_3 = (alub_reg[`AB_DE]) ? de_reg_out : 16'h0;
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assign addb_mux_4 = (alub_reg[`AB_HL]) ? hl_reg_out : 16'h0;
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assign addb_mux_5 = (alub_reg[`AB_IX]) ? ix_reg : 16'h0;
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assign addb_mux_6 = (alub_reg[`AB_IY]) ? iy_reg : 16'h0;
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assign addb_mux_7 = (alub_reg[`AB_SP]) ? sp_reg : 16'h0;
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assign addb_mux_8 = (alub_reg[`AB_DIN]) ? {din1_reg, din0_reg} : 16'h0;
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assign addb_mux_9 = (alub_reg[`AB_IO]) ? {af_reg_out[15:8], din0_reg} : 16'h0;
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assign addb_mux_10 = (alub_reg[`AB_TMP]) ? tmp_reg : 16'h0;
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assign addb_mux_12 = (alub_reg[`AB_ADR]) ? pc_reg : 16'h0;
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assign addb_in = addb_mux_2 | addb_mux_3 | addb_mux_4 | addb_mux_5 | addb_mux_6 |
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addb_mux_7 | addb_mux_8 |addb_mux_9 | addb_mux_10 | addb_mux_12;
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endmodule
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