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`include "core/uarch.sv"
module core_shifter
#(parameter W=16)
(
input shifter_control ctrl,
input logic[W - 1:0] base,
input logic[7:0] shift,
input logic c_in,
output logic[W - 1:0] q,
output logic c
);
localparam LOG = $clog2(W);
logic[W - 1:0] q_no_c, q_shl, q_shr, q_ror;
logic[W:0] sign_mask;
logic c_shl, c_shr, c_ror;
assign sign_mask = {(W + 1){ctrl.sign_extend & base[W - 1]}};
assign {c_shl, q_shl} = {c_in, base} << shift;
assign {q_shr, c_shr} = {base, c_in} >> shift | (sign_mask & ~(sign_mask >> shift));
logic ror_cycle;
logic[LOG - 1:0] ror_shift;
logic[2 * W:0] ror_out;
assign ror_shift = shift[LOG - 1:0];
assign ror_cycle = |shift[7:LOG] & ~|ror_shift;
assign ror_out = {base, base, c_in} >> {ror_cycle, ror_shift};
assign {q_ror, c_ror} = ror_out[W:0];
always_comb
if(ctrl.ror)
{c, q} = {c_ror, q_ror};
else if(ctrl.shr)
{c, q} = {c_shr, q_shr[W - 1] | (ctrl.put_carry && c_in && shift != 0), q_shr[W - 2:0]};
else
{c, q} = {c_shl, q_shl};
endmodule
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