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[/] [openrisc/] [trunk/] [or1200/] [rtl/] [verilog/] [or1200_fpu_pre_norm_div.v] - Rev 588
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////////////////////////////////////////////////////////////////////// //// //// //// or1200_fpu_pre_norm_div //// //// //// //// This file is part of the OpenRISC 1200 project //// //// http://opencores.org/project,or1k //// //// //// //// Description //// //// pre-normalization entity for the division unit //// //// //// //// To Do: //// //// //// //// //// //// Author(s): //// //// - Original design (FPU100) - //// //// Jidan Al-eryani, jidan@gmx.net //// //// - Conv. to Verilog and inclusion in OR1200 - //// //// Julius Baxter, julius@opencores.org //// //// //// ////////////////////////////////////////////////////////////////////// // // Copyright (C) 2006, 2010 // // This source file may be used and distributed without // restriction provided that this copyright statement is not // removed from the file and that any derivative work contains // the original copyright notice and the associated disclaimer. // // THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED // TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS // FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR // OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES // (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE // GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR // BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT // OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE // POSSIBILITY OF SUCH DAMAGE. // module or1200_fpu_pre_norm_div ( clk_i, opa_i, opb_i, exp_10_o, dvdnd_50_o, dvsor_27_o ); parameter FP_WIDTH = 32; parameter MUL_SERIAL = 0; // 0 for parallel multiplier, 1 for serial parameter MUL_COUNT = 11; //11 for parallel multiplier, 34 for serial parameter FRAC_WIDTH = 23; parameter EXP_WIDTH = 8; parameter ZERO_VECTOR = 31'd0; parameter INF = 31'b1111111100000000000000000000000; parameter QNAN = 31'b1111111110000000000000000000000; parameter SNAN = 31'b1111111100000000000000000000001; input clk_i; input [FP_WIDTH-1:0] opa_i; input [FP_WIDTH-1:0] opb_i; output reg [EXP_WIDTH+1:0] exp_10_o; output [2*(FRAC_WIDTH+2)-1:0] dvdnd_50_o; output [FRAC_WIDTH+3:0] dvsor_27_o; wire [EXP_WIDTH-1:0] s_expa; wire [EXP_WIDTH-1:0] s_expb; wire [FRAC_WIDTH-1:0] s_fracta; wire [FRAC_WIDTH-1:0] s_fractb; wire [2*(FRAC_WIDTH+2)-1:0] s_dvdnd_50_o; wire [FRAC_WIDTH+3:0] s_dvsor_27_o; reg [5:0] s_dvd_zeros; reg [5:0] s_div_zeros; reg [EXP_WIDTH+1:0] s_exp_10_o; reg [EXP_WIDTH+1:0] s_expa_in; reg [EXP_WIDTH+1:0] s_expb_in; wire s_opa_dn, s_opb_dn; wire [FRAC_WIDTH:0] s_fracta_24; wire [FRAC_WIDTH:0] s_fractb_24; assign s_expa = opa_i[30:23]; assign s_expb = opb_i[30:23]; assign s_fracta = opa_i[22:0]; assign s_fractb = opb_i[22:0]; assign dvdnd_50_o = s_dvdnd_50_o; assign dvsor_27_o = s_dvsor_27_o; // Output Register always @(posedge clk_i) exp_10_o <= s_exp_10_o; assign s_opa_dn = !(|s_expa); assign s_opb_dn = !(|s_expb); assign s_fracta_24 = {!s_opa_dn,s_fracta}; assign s_fractb_24 = {!s_opb_dn,s_fractb}; // count leading zeros //s_dvd_zeros <= count_l_zeros( s_fracta_24 ); always @(s_fracta_24) casez(s_fracta_24) // synopsys full_case parallel_case 24'b1???????????????????????: s_dvd_zeros = 0; 24'b01??????????????????????: s_dvd_zeros = 1; 24'b001?????????????????????: s_dvd_zeros = 2; 24'b0001????????????????????: s_dvd_zeros = 3; 24'b00001???????????????????: s_dvd_zeros = 4; 24'b000001??????????????????: s_dvd_zeros = 5; 24'b0000001?????????????????: s_dvd_zeros = 6; 24'b00000001????????????????: s_dvd_zeros = 7; 24'b000000001???????????????: s_dvd_zeros = 8; 24'b0000000001??????????????: s_dvd_zeros = 9; 24'b00000000001?????????????: s_dvd_zeros = 10; 24'b000000000001????????????: s_dvd_zeros = 11; 24'b0000000000001???????????: s_dvd_zeros = 12; 24'b00000000000001??????????: s_dvd_zeros = 13; 24'b000000000000001?????????: s_dvd_zeros = 14; 24'b0000000000000001????????: s_dvd_zeros = 15; 24'b00000000000000001???????: s_dvd_zeros = 16; 24'b000000000000000001??????: s_dvd_zeros = 17; 24'b0000000000000000001?????: s_dvd_zeros = 18; 24'b00000000000000000001????: s_dvd_zeros = 19; 24'b000000000000000000001???: s_dvd_zeros = 20; 24'b0000000000000000000001??: s_dvd_zeros = 21; 24'b00000000000000000000001?: s_dvd_zeros = 22; 24'b000000000000000000000001: s_dvd_zeros = 23; 24'b000000000000000000000000: s_dvd_zeros = 24; endcase //s_div_zeros <= count_l_zeros( s_fractb_24 ); always @(s_fractb_24) casez(s_fractb_24) // synopsys full_case parallel_case 24'b1???????????????????????: s_div_zeros = 0; 24'b01??????????????????????: s_div_zeros = 1; 24'b001?????????????????????: s_div_zeros = 2; 24'b0001????????????????????: s_div_zeros = 3; 24'b00001???????????????????: s_div_zeros = 4; 24'b000001??????????????????: s_div_zeros = 5; 24'b0000001?????????????????: s_div_zeros = 6; 24'b00000001????????????????: s_div_zeros = 7; 24'b000000001???????????????: s_div_zeros = 8; 24'b0000000001??????????????: s_div_zeros = 9; 24'b00000000001?????????????: s_div_zeros = 10; 24'b000000000001????????????: s_div_zeros = 11; 24'b0000000000001???????????: s_div_zeros = 12; 24'b00000000000001??????????: s_div_zeros = 13; 24'b000000000000001?????????: s_div_zeros = 14; 24'b0000000000000001????????: s_div_zeros = 15; 24'b00000000000000001???????: s_div_zeros = 16; 24'b000000000000000001??????: s_div_zeros = 17; 24'b0000000000000000001?????: s_div_zeros = 18; 24'b00000000000000000001????: s_div_zeros = 19; 24'b000000000000000000001???: s_div_zeros = 20; 24'b0000000000000000000001??: s_div_zeros = 21; 24'b00000000000000000000001?: s_div_zeros = 22; 24'b000000000000000000000001: s_div_zeros = 23; 24'b000000000000000000000000: s_div_zeros = 24; endcase // left-shift the dividend and divisor wire [FRAC_WIDTH:0] fracta_lshift_intermediate; wire [FRAC_WIDTH:0] fractb_lshift_intermediate; assign fracta_lshift_intermediate = s_fracta_24 << s_dvd_zeros; assign fractb_lshift_intermediate = s_fractb_24 << s_div_zeros; assign s_dvdnd_50_o = {fracta_lshift_intermediate,26'd0}; assign s_dvsor_27_o = {3'd0,fractb_lshift_intermediate}; always @(posedge clk_i) begin // pre-calculate exponent s_expa_in <= {2'd0,s_expa} + {9'd0,s_opa_dn}; s_expb_in <= {2'd0,s_expb} + {9'd0,s_opb_dn}; s_exp_10_o <= s_expa_in - s_expb_in + 10'b0001111111 - {4'd0,s_dvd_zeros} + {4'd0,s_div_zeros}; end endmodule // or1200_fpu_pre_norm_div
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