/*
    A parameterized DFF based RAM for SKY130A
    Use the COLS parameter to set the size
    Valid sizes: 1 (default), 2 or 4
*/
/*
    Author: Mohamed Shalan (mshalan@aucegypt.edu)
*/

`timescale 1ns / 1ps
`default_nettype none

module DFFRAM #( parameter COLS=4, USE_LATCH=0)
(
`ifdef USE_POWER_PINS
    VPWR,
    VGND,
`endif
    CLK,
    WE,
    EN,
    Di,
    Do,
    A
);
`ifdef USE_POWER_PINS
    input VPWR;
    input VGND;
`endif
    input           CLK;
    input   [3:0]   WE;
    input           EN;
    input   [31:0]  Di;
    output  [31:0]  Do;
    input   [7+$clog2(COLS):0]   A;

    wire [31:0]     DOUT [COLS-1:0];
    wire [31:0]     Do_pre;
    wire [COLS-1:0] EN_lines;

    wire [9:8]      A_buf;

    generate
        genvar i;
        for (i=0; i<COLS; i=i+1) begin : COLUMN
            DFFRAM_COL4 #(.USE_LATCH(USE_LATCH)) RAMCOLS (
            `ifdef USE_POWER_PINS
                .VPWR(VPWR),
                .VGND(VGND),
            `endif
                .CLK(CLK),
                .WE(WE),
                .EN(EN_lines[i]),
                .Di(Di),
                .Do(DOUT[i]),
                .A(A[7:0])
            );
        end
        if(COLS==4) begin
            sky130_fd_sc_hd__clkbuf_8 ABUF[1:0] (
            `ifdef USE_POWER_PINS
                .VPWR(VPWR),
                .VGND(VGND),
                .VPB(VPWR),
                .VNB(VGND),
            `endif
                .X(A_buf[9:8]),
                .A(A[9:8])
            );

            MUX4x1_32 MUX (
            `ifdef USE_POWER_PINS
                .VPWR(VPWR),
                .VGND(VGND),
            `endif
                .A0(DOUT[0]),
                .A1(DOUT[1]),
                .A2(DOUT[2]),
                .A3(DOUT[3]),
                .S(A_buf[9:8]),
                .X(Do_pre)
            );

            DEC2x4 DEC (
            `ifdef USE_POWER_PINS
                .VPWR(VPWR),
                .VGND(VGND),
            `endif
                .EN(EN),
                .A(A[9:8]),
                .SEL(EN_lines)
            );

        end
        else if(COLS==2) begin
            sky130_fd_sc_hd__clkbuf_8 ABUF[8:8] (
            `ifdef USE_POWER_PINS
                .VPWR(VPWR),
                .VGND(VGND),
                .VPB(VPWR),
                .VNB(VGND),
            `endif
                .X(A_buf[8]),
                .A(A[8])
            );

            MUX2x1_32 MUX (
            `ifdef USE_POWER_PINS
                .VPWR(VPWR),
                .VGND(VGND),
            `endif
                .A0(DOUT[0]),
                .A1(DOUT[1]),
                .S(A_buf[8]),
                .X(Do_pre)
            );

            //sky130_fd_sc_hd__inv_4 DEC0 ( .Y(EN_lines[0]), .A(A[8]) );
            //sky130_fd_sc_hd__clkbuf_4 DEC1 (.X(EN_lines[1]), .A(A[8]) );
            DEC1x2 DEC (
            `ifdef USE_POWER_PINS
                .VPWR(VPWR),
                .VGND(VGND),
            `endif
                .EN(EN),
                .A(A[8]),
                .SEL(EN_lines[1:0])
            );

        end
        else begin
            PASS MUX (
                .A(DOUT[0]),
                .X(Do_pre)
            );

            sky130_fd_sc_hd__clkbuf_4 ENBUF (
            `ifdef USE_POWER_PINS
                .VPWR(VPWR),
                .VGND(VGND),
                .VPB(VPWR),
                .VNB(VGND),
            `endif
                .X(EN_lines[0]),
                .A(EN)
            );
        end
    endgenerate

    sky130_fd_sc_hd__clkbuf_4 DOBUF[31:0] (
    `ifdef USE_POWER_PINS
        .VPWR(VPWR),
        .VGND(VGND),
        .VPB(VPWR),
        .VNB(VGND),
    `endif
        .X(Do),
        .A(Do_pre)
    );

endmodule