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Use Shared Imd Val Reg with Multdiv Slow

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This commit adds support for the shared immediate value register in the
id_stage for the slow implementation of the multdiv module.

Register accum_window_q is now stored in the intermediate value
register.

Signed-off-by: ganoam <gnoam@live.com>
This commit is contained in:
ganoam 2020-04-21 09:54:33 +02:00 • committed by Pirmin Vogel
parent cf33bfeae0
commit 999735568e
2 changed files with 12 additions and 2 deletions
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3
rtl/ibex_ex_block.sv
View file

@ -148,6 +148,9 @@ module ibex_ex_block #(
.valid_o ( multdiv_valid ),
.alu_operand_a_o ( multdiv_alu_operand_a ),
.alu_operand_b_o ( multdiv_alu_operand_b ),
.imd_val_q_i ( imd_val_q_i ),
.imd_val_d_o ( multdiv_imd_val_d ),
.imd_val_we_o ( multdiv_imd_val_we ),
.multdiv_ready_id_i ( multdiv_ready_id_i ),
.multdiv_result_o ( multdiv_result )
);

11
rtl/ibex_multdiv_slow.sv
View file

@ -28,6 +28,10 @@ module ibex_multdiv_slow
output logic [32:0] alu_operand_a_o,
output logic [32:0] alu_operand_b_o,
input logic [33:0] imd_val_q_i,
output logic [33:0] imd_val_d_o,
output logic imd_val_we_o,
input logic multdiv_ready_id_i,
output logic [31:0] multdiv_result_o,
@ -67,6 +71,11 @@ module ibex_multdiv_slow
// (accum_window_q + op_a_shift_q)>>1
assign res_adder_h = alu_adder_ext_i[33:1];
// Use shared intermediate value register in id_stage for accum_window
assign imd_val_d_o = accum_window_d;
assign imd_val_we_o = ~multdiv_hold;
assign accum_window_q = imd_val_q_i;
always_comb begin
alu_operand_a_o = accum_window_q;
multdiv_result_o = div_en_i ? accum_window_q[31:0] : res_adder_l;
@ -147,7 +156,6 @@ module ibex_multdiv_slow
always_ff @(posedge clk_i or negedge rst_ni) begin : proc_multdiv_state_q
if (!rst_ni) begin
multdiv_state_q <= 5'h0;
accum_window_q <= 33'h0;
op_b_shift_q <= 33'h0;
op_a_shift_q <= 33'h0;
op_numerator_q <= 32'h0;
@ -155,7 +163,6 @@ module ibex_multdiv_slow
end else begin
if (~multdiv_hold) begin
multdiv_state_q <= multdiv_state_d;
accum_window_q <= accum_window_d;
op_b_shift_q <= op_b_shift_d;
op_a_shift_q <= op_a_shift_d;
op_numerator_q <= op_numerator_d;