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[/] [openrisc/] [trunk/] [or1200/] [rtl/] [verilog/] [or1200_fpu_fcmp.v] - Rev 349
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///////////////////////////////////////////////////////////////////// //// //// //// or1200_fpu_fcmp //// //// Single precision Floating Point Compare Unit //// //// //// //// Author: Rudolf Usselmann //// //// rudi@asics.ws //// //// //// ///////////////////////////////////////////////////////////////////// //// //// //// Copyright (C) 2000 Rudolf Usselmann //// //// rudi@asics.ws //// //// //// //// 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. //// //// //// ///////////////////////////////////////////////////////////////////// `timescale 1ns / 100ps module or1200_fpu_fcmp(opa, opb, unordered, altb, blta, aeqb, inf, zero); input [31:0] opa, opb; output unordered; output altb, blta, aeqb; output inf, zero; //////////////////////////////////////////////////////////////////////// // // Local Wire // reg altb, blta, aeqb; wire signa, signb; wire [7:0] expa, expb; wire [22:0] fracta, fractb; wire expa_ff, expb_ff, fracta_00, fractb_00; wire qnan_a, snan_a, qnan_b, snan_b, opa_inf, opb_inf, inf; wire qnan, snan, opa_zero, opb_zero; wire exp_eq, exp_gt, exp_lt; wire fract_eq, fract_gt, fract_lt; wire all_zero; //////////////////////////////////////////////////////////////////////// // // Aliases // assign signa = opa[31]; assign signb = opb[31]; assign expa = opa[30:23]; assign expb = opb[30:23]; assign fracta = opa[22:0]; assign fractb = opb[22:0]; //////////////////////////////////////////////////////////////////////// // // Exception Logic // assign expa_ff = &expa; assign expb_ff = &expb; assign fracta_00 = !(|fracta); assign fractb_00 = !(|fractb); assign qnan_a = fracta[22]; assign snan_a = !fracta[22] & |fracta[21:0]; assign qnan_b = fractb[22]; assign snan_b = !fractb[22] & |fractb[21:0]; assign opa_inf = (expa_ff & fracta_00); assign opb_inf = (expb_ff & fractb_00); assign inf = opa_inf | opb_inf; assign qnan = (expa_ff & qnan_a) | (expb_ff & qnan_b); assign snan = (expa_ff & snan_a) | (expb_ff & snan_b); assign unordered = qnan | snan; assign opa_zero = !(|expa) & fracta_00; assign opb_zero = !(|expb) & fractb_00; assign zero = opa_zero; //////////////////////////////////////////////////////////////////////// // // Comparison Logic // assign exp_eq = expa == expb; assign exp_gt = expa > expb; assign exp_lt = expa < expb; assign fract_eq = fracta == fractb; assign fract_gt = fracta > fractb; assign fract_lt = fracta < fractb; assign all_zero = opa_zero & opb_zero; always @( qnan or snan or opa_inf or opb_inf or signa or signb or exp_eq or exp_gt or exp_lt or fract_eq or fract_gt or fract_lt or all_zero) casex( {qnan, snan, opa_inf, opb_inf, signa, signb, exp_eq, exp_gt, exp_lt, fract_eq, fract_gt, fract_lt, all_zero}) //13'b??_??_??_???_???_?: {altb, blta, aeqb} = 3'b000; 13'b1?_??_??_???_???_?: {altb, blta, aeqb} = 3'b000; // qnan 13'b?1_??_??_???_???_?: {altb, blta, aeqb} = 3'b000; // snan 13'b00_11_00_???_???_?: {altb, blta, aeqb} = 3'b001; // both op INF comparisson 13'b00_11_01_???_???_?: {altb, blta, aeqb} = 3'b100; 13'b00_11_10_???_???_?: {altb, blta, aeqb} = 3'b010; 13'b00_11_11_???_???_?: {altb, blta, aeqb} = 3'b001; 13'b00_10_00_???_???_?: {altb, blta, aeqb} = 3'b100; // opa INF comparisson 13'b00_10_01_???_???_?: {altb, blta, aeqb} = 3'b100; 13'b00_10_10_???_???_?: {altb, blta, aeqb} = 3'b010; 13'b00_10_11_???_???_?: {altb, blta, aeqb} = 3'b010; 13'b00_01_00_???_???_?: {altb, blta, aeqb} = 3'b010; // opb INF comparisson 13'b00_01_01_???_???_?: {altb, blta, aeqb} = 3'b100; 13'b00_01_10_???_???_?: {altb, blta, aeqb} = 3'b010; 13'b00_01_11_???_???_?: {altb, blta, aeqb} = 3'b100; 13'b00_00_10_???_???_0: {altb, blta, aeqb} = 3'b010; //compare base on sign 13'b00_00_01_???_???_0: {altb, blta, aeqb} = 3'b100; //compare base on sign 13'b00_00_??_???_???_1: {altb, blta, aeqb} = 3'b001; //compare base on sign both are zero 13'b00_00_00_010_???_?: {altb, blta, aeqb} = 3'b100; // cmp exp, equal sign 13'b00_00_00_001_???_?: {altb, blta, aeqb} = 3'b010; 13'b00_00_11_010_???_?: {altb, blta, aeqb} = 3'b010; 13'b00_00_11_001_???_?: {altb, blta, aeqb} = 3'b100; 13'b00_00_00_100_010_?: {altb, blta, aeqb} = 3'b100; // compare fractions, equal sign, equal exp 13'b00_00_00_100_001_?: {altb, blta, aeqb} = 3'b010; 13'b00_00_11_100_010_?: {altb, blta, aeqb} = 3'b010; 13'b00_00_11_100_001_?: {altb, blta, aeqb} = 3'b100; 13'b00_00_00_100_100_?: {altb, blta, aeqb} = 3'b001; 13'b00_00_11_100_100_?: {altb, blta, aeqb} = 3'b001; default: {altb, blta, aeqb} = 3'bxxx; endcase endmodule // or1200_fpu_fcmp
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