diff options
Diffstat (limited to 'src/rtl')
| -rw-r--r-- | src/rtl/montprod.v | 86 |
1 files changed, 68 insertions, 18 deletions
diff --git a/src/rtl/montprod.v b/src/rtl/montprod.v index fa7c438..7276b4b 100644 --- a/src/rtl/montprod.v +++ b/src/rtl/montprod.v @@ -132,7 +132,13 @@ module montprod #(parameter OPW = 32, parameter ADW = 8) reg [(ADW - 1) : 0] word_index_reg; reg [(ADW - 1) : 0] word_index_new; + reg word_index_we; reg [(ADW - 1) : 0] word_index_prev_reg; + reg reset_word_index_lsw; + reg reset_word_index_msw; + reg inc_word_index; + reg dec_word_index; + reg [(ADW - 1) : 0] length_m1; reg add_carry_in_sa_reg; @@ -161,12 +167,13 @@ module montprod #(parameter OPW = 32, parameter ADW = 8) wire shr_carry_out; wire [(OPW - 1) : 0] shr_data_out; - reg reset_word_index_lsw; - reg reset_word_index_msw; reg [(OPW - 1) : 0] sa_adder_data_in; reg [(OPW - 1) : 0] muxed_s_mem_read_data; + // Temporary debug wires. + reg b_js; + reg pr_tt; //---------------------------------------------------------------- @@ -253,13 +260,15 @@ module montprod #(parameter OPW = 32, parameter ADW = 8) 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; shr_carry_in_reg <= shr_carry_in_new; add_carry_in_sa_reg <= add_carry_in_sa_new; add_carry_in_sm_reg <= add_carry_in_sm_new; + if (word_index_we) + word_index_reg <= word_index_new; + if (first_iteration_we) first_iteration_reg <= first_iteration_new; @@ -288,46 +297,74 @@ module montprod #(parameter OPW = 32, parameter ADW = 8) //---------------------------------------------------------------- // prodcalc + // + // Logic to generate addresses and data selection + // for the OpA, OpM and Result memories. //---------------------------------------------------------------- always @* begin : prodcalc opa_addr_reg = word_index_reg; opb_addr_reg = b_word_index; opm_addr_reg = word_index_reg; - s_mem_addr = word_index_reg; tmp_result_we = 1'b0; - result_addr_reg = word_index_prev_reg; result_data_reg = s_mem_read_data; - if (montprod_ctrl_reg == CTRL_LOOP_ITER) begin opa_addr_reg = length_m1; - s_mem_addr = length_m1; end if (montprod_ctrl_reg == CTRL_EMIT_S) tmp_result_we = 1'b1; + end // prodcalc + + + //---------------------------------------------------------------- + // word_index + // + // Logic that implements the word index used to drive + // addresses for operands. + //---------------------------------------------------------------- + always @* + begin : word_index + word_index_new = {ADW{1'b0}}; + word_index_we = 1'b0; if (reset_word_index_lsw) - word_index_new = length_m1; + begin + word_index_new = length_m1; + word_index_we = 1'b1; + end - else if (reset_word_index_msw) - word_index_new = {ADW{1'b0}}; + if (reset_word_index_msw) + begin + word_index_new = {ADW{1'b0}}; + word_index_we = 1'b1; + end - else if (montprod_ctrl_reg == CTRL_CALC_SDIV2) - word_index_new = word_index_reg + 1'b1; + if (inc_word_index) + begin + word_index_new = word_index_reg + 1'b1; + word_index_we = 1'b1; + end - else - word_index_new = word_index_reg - 1'b1; - end // prodcalc + if (dec_word_index) + begin + word_index_new = word_index_reg - 1'b1; + word_index_we = 1'b1; + end + end // word_index //---------------------------------------------------------------- // s_logic + // + // Logic to calculate S memory updates including address + // and write enable. This is where the main montprod + // calculation is performed. //---------------------------------------------------------------- always @* begin : s_logic @@ -338,7 +375,7 @@ module montprod #(parameter OPW = 32, parameter ADW = 8) add_carry_in_sm_new = 1'b0; s_mem_new = {OPW{1'b0}}; s_mem_we_new = 1'b0; - + s_mem_addr = word_index_reg; case (montprod_ctrl_reg) CTRL_INIT_S: @@ -346,6 +383,11 @@ module montprod #(parameter OPW = 32, parameter ADW = 8) s_mem_we_new = 1'b1; end + CTRL_LOOP_ITER: + begin + s_mem_addr = length_m1; + end + CTRL_CALC_ADD: begin //s = (s + q*M + b*A) >>> 1;, if(b==1) S+= A. Takes (1..length) cycles. @@ -461,6 +503,8 @@ module montprod #(parameter OPW = 32, parameter ADW = 8) b_bit_index_we = 1'b0; bq_we = 1'b0; s_mux_new = SMUX_0; + dec_word_index = 1'b0; + inc_word_index = 1'b0; reset_word_index_lsw = 1'b0; reset_word_index_msw = 1'b0; first_iteration_new = 1'b0; @@ -485,6 +529,8 @@ module montprod #(parameter OPW = 32, parameter ADW = 8) CTRL_INIT_S: begin + dec_word_index = 1'b1; + if (word_index_reg == 0) begin loop_ctr_set = 1'b1; @@ -519,7 +565,8 @@ module montprod #(parameter OPW = 32, parameter ADW = 8) CTRL_CALC_ADD: begin - s_mux_new = SMUX_ADD; + s_mux_new = SMUX_ADD; + dec_word_index = 1'b1; if (word_index_reg == 0) begin @@ -540,7 +587,8 @@ module montprod #(parameter OPW = 32, parameter ADW = 8) CTRL_CALC_SDIV2: begin - s_mux_new = SMUX_SHR; + s_mux_new = SMUX_SHR; + inc_word_index = 1'b1; if (word_index_reg == length_m1) begin @@ -571,6 +619,8 @@ module montprod #(parameter OPW = 32, parameter ADW = 8) CTRL_EMIT_S: begin + dec_word_index = 1'b1; + if (word_index_prev_reg == 0) begin ready_new = 1'b1; |