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-rw-r--r--src/rtl/montprod.v165
1 files changed, 74 insertions, 91 deletions
diff --git a/src/rtl/montprod.v b/src/rtl/montprod.v
index 7c7bf33..9748b09 100644
--- a/src/rtl/montprod.v
+++ b/src/rtl/montprod.v
@@ -70,14 +70,12 @@ module montprod(
localparam CTRL_WAIT = 4'h2;
localparam CTRL_LOOP_ITER = 4'h3;
localparam CTRL_LOOP_BQ = 4'h4;
- localparam CTRL_L_CALC_SM = 4'h5;
- localparam CTRL_L_STALLPIPE_SM = 4'h6;
- localparam CTRL_L_CALC_SA = 4'h7;
- localparam CTRL_L_STALLPIPE_SA = 4'h8;
- localparam CTRL_L_CALC_SDIV2 = 4'h9;
- localparam CTRL_L_STALLPIPE_D2 = 4'hA;
- localparam CTRL_L_STALLPIPE_ES = 4'hB;
- localparam CTRL_EMIT_S = 4'hC;
+ localparam CTRL_L_CALC_SA = 4'h5;
+ localparam CTRL_L_STALLPIPE_SA = 4'h6;
+ localparam CTRL_L_CALC_SDIV2 = 4'h7;
+ localparam CTRL_L_STALLPIPE_D2 = 4'h8;
+ localparam CTRL_L_STALLPIPE_ES = 4'h9;
+ localparam CTRL_EMIT_S = 4'ha;
localparam SMUX_0 = 2'h0;
localparam SMUX_ADD_SM = 2'h1;
@@ -117,7 +115,7 @@ module montprod(
reg q_reg;
reg b_new;
reg b_reg;
- reg update_bq;
+ reg bq_we;
reg [12 : 0] loop_ctr_reg;
reg [12 : 0] loop_ctr_new;
@@ -125,9 +123,11 @@ module montprod(
reg loop_ctr_set;
reg loop_ctr_dec;
- reg [07 : 0] B_word_index; //loop counter as a word index
- reg [04 : 0] B_bit_index; //loop counter as a bit index
- reg [04 : 0] B_bit_index_reg; //loop counter as a bit index
+ reg [07 : 0] b_word_index; //loop counter as a word index
+
+ reg [04 : 0] b_bit_index_reg;
+ reg [04 : 0] b_bit_index_new;
+ reg [04 : 0] b_bit_index_we;
reg [07 : 0] word_index_reg; //register of what word is being read
reg [07 : 0] word_index_new; //calculation of what word to be read
@@ -142,8 +142,10 @@ module montprod(
reg shr_carry_in_reg;
reg shr_carry_in_new;
- reg reset_word_index_LSW;
- reg reset_word_index_MSW;
+ reg reset_word_index_lsw;
+ reg reset_word_index_msw;
+
+ reg [31 : 0] sa_adder_data_in;
//----------------------------------------------------------------
@@ -155,10 +157,10 @@ module montprod(
wire [31 : 0] add_result_sm;
wire add_carry_out_sm;
+ reg shr_data_in;
wire shr_carry_out;
- wire [31 : 0] shr_adiv2;
+ wire [31 : 0] shr_data_out;
- reg set_B_bit_index;
//----------------------------------------------------------------
@@ -198,7 +200,7 @@ module montprod(
adder32 s_adder_sa(
- .a(s_mem_read_data),
+ .a(sa_adder_data_in),
.b(opa_data),
.carry_in(add_carry_in_sa_reg),
.sum(add_result_sa),
@@ -208,7 +210,7 @@ module montprod(
shr32 shifter(
.a(s_mem_read_data),
.carry_in(shr_carry_in_reg),
- .adiv2(shr_adiv2),
+ .adiv2(shr_data_out),
.carry_out(shr_carry_out)
);
@@ -225,7 +227,7 @@ module montprod(
if (!reset_n)
begin
ready_reg <= 1'b0;
- loop_ctr_reg <= 13'h0;
+ loop_ctr_reg <= 13'h0;
word_index_reg <= 8'h0;
word_index_prev_reg <= 8'h0;
add_carry_in_sa_reg <= 1'b0;
@@ -236,13 +238,14 @@ module montprod(
s_mux_reg <= SMUX_0;
s_mem_we_reg <= 1'b0;
s_mem_wr_addr_reg <= 8'h0;
- B_bit_index_reg <= 5'h0;
+ b_bit_index_reg <= 5'h0;
montprod_ctrl_reg <= CTRL_IDLE;
end
else
begin
- s_mem_wr_addr_reg <= s_mem_addr;
- s_mem_we_reg <= s_mem_we_new;
+ s_mem_wr_addr_reg <= s_mem_addr;
+ s_mem_we_reg <= s_mem_we_new;
+ s_mux_reg <= s_mux_new;
word_index_reg <= word_index_new;
word_index_prev_reg <= word_index_reg;
@@ -251,14 +254,14 @@ module montprod(
add_carry_in_sa_reg <= add_carry_in_sa_new;
add_carry_in_sm_reg <= add_carry_in_sm_new;
- B_bit_index_reg <= B_bit_index;
+ if (b_bit_index_we)
+ b_bit_index_reg <= b_bit_index_new;
- if (update_bq)
+ if (bq_we)
begin
b_reg <= b_new;
q_reg <= q_new;
end
- s_mux_reg <= s_mux_new;
if (ready_we)
ready_reg <= ready_new;
@@ -279,7 +282,7 @@ module montprod(
//----------------------------------------------------------------
always @*
begin : prodcalc
- opb_addr_reg = B_word_index;
+ opb_addr_reg = b_word_index;
opm_addr_reg = word_index_reg;
result_addr_reg = word_index_prev_reg;
@@ -309,10 +312,10 @@ module montprod(
endcase
- if (reset_word_index_LSW == 1'b1)
+ if (reset_word_index_lsw == 1'b1)
word_index_new = length_m1;
- else if (reset_word_index_MSW == 1'b1)
+ else if (reset_word_index_msw == 1'b1)
word_index_new = 8'h0;
else if (montprod_ctrl_reg == CTRL_L_CALC_SDIV2)
@@ -331,6 +334,7 @@ module montprod(
shr_carry_in_new = 1'b0;
s_mux_new = SMUX_0;
s_mem_we_new = 1'b0;
+ sa_adder_data_in = 32'h0;
case (montprod_ctrl_reg)
CTRL_INIT_S:
@@ -339,18 +343,11 @@ module montprod(
s_mem_we_new = 1'b1;
end
- CTRL_L_CALC_SM:
- begin
- //s = (s + q*M + b*A) >>> 1;, if(q==1) S+= M. Takes (1..length) cycles.
- s_mux_new = SMUX_ADD_SM;
- s_mem_we_new = q_reg;
- end
-
CTRL_L_CALC_SA:
begin
//s = (s + q*M + b*A) >>> 1;, if(b==1) S+= A. Takes (1..length) cycles.
s_mux_new = SMUX_ADD_SA;
- s_mem_we_new = b_reg;
+ s_mem_we_new = b_reg | q_reg;
end
CTRL_L_CALC_SDIV2:
@@ -373,21 +370,26 @@ module montprod(
SMUX_0:
s_mem_new = 32'h0;
- SMUX_ADD_SM:
- begin
- s_mem_new = add_result_sm;
- add_carry_in_sm_new = add_carry_out_sm;
- end
-
SMUX_ADD_SA:
begin
- s_mem_new = add_result_sa;
+ if (q_reg)
+ sa_adder_data_in = add_result_sm;
+ else
+ sa_adder_data_in = s_mem_read_data;
+
+ if (b_reg)
+ s_mem_new = add_result_sa;
+ else
+ s_mem_new = add_result_sm;
+
add_carry_in_sa_new = add_carry_out_sa;
+ add_carry_in_sm_new = add_carry_out_sm;
end
SMUX_SHR:
begin
- s_mem_new = shr_adiv2;
+ shr_data_in = s_mem_read_data;
+ s_mem_new = shr_data_out;
shr_carry_in_new = shr_carry_out;
end
@@ -400,12 +402,14 @@ module montprod(
//----------------------------------------------------------------
// bq
- // b: bit of B
+ //
+ // Extract b and q bits.
+ // b: current bit of B used.
// q = (s - b * A) & 1
//----------------------------------------------------------------
always @*
begin : bq
- b_new = opb_data[B_bit_index_reg];
+ b_new = opb_data[b_bit_index_reg];
q_new = s_mem_read_data[0] ^ (opa_data[0] & b_new);
end // bq
@@ -417,11 +421,12 @@ module montprod(
//----------------------------------------------------------------
always @*
begin : loop_ctr
- loop_ctr_new = loop_ctr_reg;
- loop_ctr_we = 1'b0;
+ loop_ctr_new = 13'h0;
+ loop_ctr_we = 1'b0;
length_m1 = length - 1'b1;
- B_bit_index = B_bit_index_reg;
- B_word_index = loop_ctr_reg[12:5];
+
+ b_bit_index_new = 5'h1f - loop_ctr_reg[4:0];
+ b_word_index = loop_ctr_reg[12:5];
if (loop_ctr_set)
begin
@@ -434,11 +439,6 @@ module montprod(
loop_ctr_new = loop_ctr_reg - 1'b1;
loop_ctr_we = 1'b1;
end
-
- if (set_B_bit_index)
- begin
- B_bit_index = 5'h1f - loop_ctr_reg[4:0];
- end
end
@@ -449,18 +449,18 @@ module montprod(
//----------------------------------------------------------------
always @*
begin : montprod_ctrl
- ready_new = 1'b0;
- ready_we = 1'b0;
- montprod_ctrl_new = CTRL_IDLE;
- montprod_ctrl_we = 1'b0;
+ ready_new = 1'b0;
+ ready_we = 1'b0;
+ montprod_ctrl_new = CTRL_IDLE;
+ montprod_ctrl_we = 1'b0;
- loop_ctr_set = 1'b0;
- loop_ctr_dec = 1'b0;
- set_B_bit_index = 1'b0;
- update_bq = 1'b0;
+ loop_ctr_set = 1'b0;
+ loop_ctr_dec = 1'b0;
+ b_bit_index_we = 1'b0;
+ bq_we = 1'b0;
- reset_word_index_LSW = 1'b0;
- reset_word_index_MSW = 1'b0;
+ reset_word_index_lsw = 1'b0;
+ reset_word_index_msw = 1'b0;
case (montprod_ctrl_reg)
@@ -472,7 +472,7 @@ module montprod(
ready_we = 1'b1;
montprod_ctrl_new = CTRL_INIT_S;
montprod_ctrl_we = 1'b1;
- reset_word_index_LSW = 1'b1;
+ reset_word_index_lsw = 1'b1;
end
else
begin
@@ -501,42 +501,25 @@ module montprod(
// Also abort loop if done.
CTRL_LOOP_ITER:
begin
- set_B_bit_index = 1'b1;
- reset_word_index_LSW = 1'b1;
+ b_bit_index_we = 1'b1;
+ reset_word_index_lsw = 1'b1;
montprod_ctrl_new = CTRL_LOOP_BQ;
montprod_ctrl_we = 1'b1;
end
CTRL_LOOP_BQ:
begin
- reset_word_index_LSW = 1'b1;
- update_bq = 1'b1;
- montprod_ctrl_new = CTRL_L_CALC_SM;
- montprod_ctrl_we = 1'b1;
- end
-
- CTRL_L_CALC_SM:
- begin
- if (word_index_reg == 8'h0)
- begin
- reset_word_index_LSW = 1'b1;
- montprod_ctrl_we = 1'b1;
- montprod_ctrl_new = CTRL_L_STALLPIPE_SM;
- end
- end
-
- CTRL_L_STALLPIPE_SM:
- begin
+ reset_word_index_lsw = 1'b1;
+ bq_we = 1'b1;
montprod_ctrl_new = CTRL_L_CALC_SA;
montprod_ctrl_we = 1'b1;
- reset_word_index_LSW = 1'b1;
end
CTRL_L_CALC_SA:
begin
if (word_index_reg == 8'h0)
begin
- reset_word_index_LSW = 1'b1;
+ reset_word_index_lsw = 1'b1;
montprod_ctrl_new = CTRL_L_STALLPIPE_SA;
montprod_ctrl_we = 1'b1;
end
@@ -546,7 +529,7 @@ module montprod(
begin
montprod_ctrl_new = CTRL_L_CALC_SDIV2;
montprod_ctrl_we = 1'b1;
- reset_word_index_MSW = 1'b1;
+ reset_word_index_msw = 1'b1;
end
CTRL_L_CALC_SDIV2:
@@ -560,10 +543,10 @@ module montprod(
CTRL_L_STALLPIPE_D2:
begin
- loop_ctr_dec = 1'b1;
+ loop_ctr_dec = 1'b1;
montprod_ctrl_new = CTRL_LOOP_ITER;
montprod_ctrl_we = 1'b1;
- reset_word_index_LSW = 1'b1;
+ reset_word_index_lsw = 1'b1;
if (loop_ctr_reg == 0)
begin
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-23 18:24:10 +0000