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|
module \$__COUNT_ (CE, CLK, OUT, POUT, RST, UP);
input wire CE;
input wire CLK;
output wire OUT;
(* force_downto *)
output wire[WIDTH-1:0] POUT;
input wire RST;
input wire UP;
parameter COUNT_TO = 1;
parameter RESET_MODE = "RISING";
parameter RESET_TO_MAX = 0;
parameter HAS_POUT = 0;
parameter HAS_CE = 0;
parameter WIDTH = 8;
parameter DIRECTION = "DOWN";
if (DIRECTION == "UP") begin
if (WIDTH < 2) begin
initial begin
$display("ERROR: \$__COUNT_ must be at least 2 bits wide (bug in extract_counter pass?).");
$finish;
end
end
// FIXME: Max width?
assign OUT = POUT == COUNT_TO;
if (HAS_CE) begin
genvar i;
for (i = 0; i < WIDTH; i++) begin: countbits
// each bit = (cur & !reset) ^ (all prev & !reset)
wire xor_to_mc_bitn;
FDCP #(
.INIT(0)
) bitn_ff (
.C(CLK),
.CLR(0),
.D(xor_to_mc_bitn),
.PRE(0),
.Q(POUT[i])
);
wire orterm_to_xor_bitn;
wire pterm0_to_or_bitn;
wire pterm1_to_or_bitn;
MACROCELL_XOR #(
.INVERT_OUT(0)
) bitn_xor (
.IN_ORTERM(orterm_to_xor_bitn),
.IN_PTC(pterm1_to_or_bitn),
.OUT(xor_to_mc_bitn)
);
ORTERM #(
.WIDTH(1)
) bitn_or (
.IN(pterm0_to_or_bitn),
.OUT(orterm_to_xor_bitn)
);
ANDTERM #(
.COMP_INP(1),
.TRUE_INP(1)
) bitn_pterm0 (
.IN(POUT[i]),
.IN_B(OUT),
.OUT(pterm0_to_or_bitn)
);
ANDTERM #(
.COMP_INP(1),
.TRUE_INP(i + 1)
) bitn_pterm1 (
.IN({POUT[i-1:0], CE}),
.IN_B(OUT),
.OUT(pterm1_to_or_bitn)
);
end
end else begin
// Bit0 is special; toggle unless reset
// cur reset out
// 0 0 1
// 0 1 0
// 1 0 0
// 1 1 0
wire xor_to_mc_bit0;
FDCP #(
.INIT(0)
) bit0_ff (
.C(CLK),
.CLR(0),
.D(xor_to_mc_bit0),
.PRE(0),
.Q(POUT[0])
);
wire pterm_to_xor_bit0;
MACROCELL_XOR #(
.INVERT_OUT(0)
) bit0_xor (
.IN_PTC(pterm_to_xor_bit0),
.OUT(xor_to_mc_bit0)
);
ANDTERM #(
.COMP_INP(2),
.TRUE_INP(0)
) bit0_pterm (
.IN(),
.IN_B({POUT[0], OUT}),
.OUT(pterm_to_xor_bit0)
);
genvar i;
for (i = 1; i < WIDTH; i++) begin: countbits
// each bit = (cur & !reset) ^ (all prev & !reset)
wire xor_to_mc_bitn;
FDCP #(
.INIT(0)
) bitn_ff (
.C(CLK),
.CLR(0),
.D(xor_to_mc_bitn),
.PRE(0),
.Q(POUT[i])
);
wire orterm_to_xor_bitn;
wire pterm0_to_or_bitn;
wire pterm1_to_or_bitn;
MACROCELL_XOR #(
.INVERT_OUT(0)
) bitn_xor (
.IN_ORTERM(orterm_to_xor_bitn),
.IN_PTC(pterm1_to_or_bitn),
.OUT(xor_to_mc_bitn)
);
ORTERM #(
.WIDTH(1)
) bitn_or (
.IN(pterm0_to_or_bitn),
.OUT(orterm_to_xor_bitn)
);
ANDTERM #(
.COMP_INP(1),
.TRUE_INP(1)
) bitn_pterm0 (
.IN(POUT[i]),
.IN_B(OUT),
.OUT(pterm0_to_or_bitn)
);
ANDTERM #(
.COMP_INP(1),
.TRUE_INP(i)
) bitn_pterm1 (
.IN(POUT[i-1:0]),
.IN_B(OUT),
.OUT(pterm1_to_or_bitn)
);
end
end
end
// FIXME: down counters
endmodule
|
