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//
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//
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// fpAddsub.v
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// fpAddsub.v
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// - floating point adder/subtracter
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// - floating point adder/subtracter
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// - ten cycle latency
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// - ten cycle latency
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// - can issue every clock cycle
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// - can issue every clock cycle
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// - parameterized FPWIDth
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// - parameterized width
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// - IEEE 754 representation
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// - IEEE 754 representation
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//
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//
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//
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//
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// This source file is free software: you can redistribute it and/or modify
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// This source file is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published
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// it under the terms of the GNU Lesser General Public License as published
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reg [EMSB:0] xdiff3;
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reg [EMSB:0] xdiff3;
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// which has greater magnitude ? Used for sign calc
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// which has greater magnitude ? Used for sign calc
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reg a_gt_b3;
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reg a_gt_b3;
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reg resZero3;
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reg resZero3;
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reg [FMSB+1:0] mfs3;
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reg [FMSB+1:0] mfs3;
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wire aNan3, bNan3;
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delay1 #(EMSB+1) dxa3(.clk(clk), .ce(ce), .i(xa2), .o(xa3));
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delay1 #(EMSB+1) dxa3(.clk(clk), .ce(ce), .i(xa2), .o(xa3));
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delay1 #(EMSB+1) dxb3(.clk(clk), .ce(ce), .i(xb2), .o(xb3));
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delay1 #(EMSB+1) dxb3(.clk(clk), .ce(ce), .i(xb2), .o(xb3));
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delay1 #(1) dxabInf2(.clk(clk), .ce(ce), .i(xabInf2), .o(xabInf3));
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delay1 #(1) dxabInf2(.clk(clk), .ce(ce), .i(xabInf2), .o(xabInf3));
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delay1 #(1) dxagtxb2(.clk(clk), .ce(ce), .i(xa_gt_xb2), .o(xa_gt_xb3));
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delay1 #(1) dxagtxb2(.clk(clk), .ce(ce), .i(xa_gt_xb2), .o(xa_gt_xb3));
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delay2 #(1) dsa2(.clk(clk), .ce(ce), .i(sa1), .o(sa3));
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delay2 #(1) dsa2(.clk(clk), .ce(ce), .i(sa1), .o(sa3));
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delay2 #(1) dsb2(.clk(clk), .ce(ce), .i(sb1), .o(sb3));
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delay2 #(1) dsb2(.clk(clk), .ce(ce), .i(sb1), .o(sb3));
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delay2 #(1) dop2(.clk(clk), .ce(ce), .i(op1), .o(op3));
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delay2 #(1) dop2(.clk(clk), .ce(ce), .i(op1), .o(op3));
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delay3 #(3) drm2(.clk(clk), .ce(ce), .i(rm), .o(rm3));
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delay3 #(3) drm2(.clk(clk), .ce(ce), .i(rm), .o(rm3));
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delay2 #(1) dan2(.clk(clk), .ce(ce), .i(aNan1), .o(aNan3));
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delay2 #(1) dbn2(.clk(clk), .ce(ce), .i(bNan1), .o(bNan3));
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always @(posedge clk)
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always @(posedge clk)
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if (ce) a_gt_b3 <= xa_gt_xb2 || var2;
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if (ce) a_gt_b3 <= xa_gt_xb2 || var2;
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// Find out if the result will be zero.
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// Find out if the result will be zero.
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always @(posedge clk)
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always @(posedge clk)
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if (ce) xo4 <= xabInf3 ? xa3 : resZero3 ? {EMSB+1{1'b0}} : xa_gt_xb3 ? xa3 : xb3;
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if (ce) xo4 <= xabInf3 ? xa3 : resZero3 ? {EMSB+1{1'b0}} : xa_gt_xb3 ? xa3 : xb3;
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// Compute output sign
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// Compute output sign
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always @(posedge clk)
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always @(posedge clk)
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if (ce)
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if (ce)
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case ({resZero3,sa3,op3,sb3}) // synopsys full_case parallel_case
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casez ({aNan3,bNan3,resZero3,sa3,op3,sb3}) // synopsys full_case parallel_case
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4'b0000: so4 <= 0; // + + + = +
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6'b10????: so4 <= sa3;
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4'b0001: so4 <= !a_gt_b3; // + + - = sign of larger
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6'b01????: so4 <= sb3;
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4'b0010: so4 <= !a_gt_b3; // + - + = sign of larger
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6'b11????: so4 <= a_gt_b3 ? sa3 : sb3;
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4'b0011: so4 <= 0; // + - - = +
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6'b000000: so4 <= 0; // + + + = +
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4'b0100: so4 <= a_gt_b3; // - + + = sign of larger
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6'b000001: so4 <= a_gt_b3 ? 1'b0 : 1'b1; // + + - = sign of larger
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4'b0101: so4 <= 1; // - + - = -
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6'b000010: so4 <= a_gt_b3 ? 1'b0 : 1'b1; // + - + = sign of larger
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4'b0110: so4 <= 1; // - - + = -
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6'b000011: so4 <= 0; // + - - = +
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4'b0111: so4 <= a_gt_b3; // - - - = sign of larger
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6'b000100: so4 <= a_gt_b3 ? 1'b1 : 1'b0; // - + + = sign of larger
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4'b1000: so4 <= 0; // A + B, sign = +
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6'b000101: so4 <= 1; // - + - = -
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4'b1001: so4 <= rm3==3'd3; // A + -B, sign = + unless rounding down
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6'b000110: so4 <= 1; // - - + = -
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4'b1010: so4 <= rm3==3'd3; // A - B, sign = + unless rounding down
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6'b000111: so4 <= a_gt_b3 ? 1'b1 : 1'b0; // - - - = sign of larger
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4'b1011: so4 <= 0; // +A - -B, sign = +
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4'b1100: so4 <= rm3==3'd3; // -A + B, sign = + unless rounding down
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6'b001000: so4 <= 0; // A + B, sign = +
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4'b1101: so4 <= 1; // -A + -B, sign = -
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6'b001001: so4 <= rm3==3'd3; // A + -B, sign = + unless rounding down
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4'b1110: so4 <= 1; // -A - +B, sign = -
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6'b001010: so4 <= rm3==3'd3; // A - B, sign = + unless rounding down
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4'b1111: so4 <= rm3==3'd3; // -A - -B, sign = + unless rounding down
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6'b001011: so4 <= 0; // +A - -B, sign = +
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6'b001100: so4 <= rm3==3'd3; // -A + B, sign = + unless rounding down
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6'b001101: so4 <= 1; // -A + -B, sign = -
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6'b001110: so4 <= 1; // -A - +B, sign = -
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6'b001111: so4 <= rm3==3'd3; // -A - -B, sign = + unless rounding down
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endcase
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endcase
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always @(posedge clk)
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always @(posedge clk)
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if (ce) xdif4 <= xdiff3 > FMSB+3 ? FMSB+3 : xdiff3;
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if (ce) xdif4 <= xdiff3 > FMSB+3 ? FMSB+3 : xdiff3;
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delay1 #(FMSB+2) dmsf3(.clk(clk), .ce(ce), .i(mfs3), .o(mfs4));
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delay1 #(FMSB+2) dmsf3(.clk(clk), .ce(ce), .i(mfs3), .o(mfs4));
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delay1 #(EMSB+1) dxdif4(.clk(clk), .ce(ce), .i(xdif4), .o(xdif5) );
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delay1 #(EMSB+1) dxdif4(.clk(clk), .ce(ce), .i(xdif4), .o(xdif5) );
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delay1 #(FMSB+2) dmsf4(.clk(clk), .ce(ce), .i(mfs4), .o(mfs5));
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delay1 #(FMSB+2) dmsf4(.clk(clk), .ce(ce), .i(mfs4), .o(mfs5));
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generate
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generate
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begin
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begin
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if (FPWID+`EXTRA_BITS==128)
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if (FPWID==128)
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redor128 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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redor128 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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else if (FPWID+`EXTRA_BITS==96)
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else if (FPWID==96)
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redor96 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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redor96 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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else if (FPWID+`EXTRA_BITS==84)
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else if (FPWID==84)
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redor84 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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redor84 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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else if (FPWID+`EXTRA_BITS==80)
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else if (FPWID==80)
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redor80 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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redor80 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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else if (FPWID+`EXTRA_BITS==64)
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else if (FPWID==64)
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redor64 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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redor64 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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else if (FPWID+`EXTRA_BITS==40)
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else if (FPWID==40)
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redor40 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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redor40 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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else if (FPWID+`EXTRA_BITS==32)
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else if (FPWID==32)
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redor32 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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redor32 u1 (.a(xdif4), .b({mfs4,2'b0}), .o(sticky) );
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end
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end
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endgenerate
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endgenerate
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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always @(posedge clk)
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always @(posedge clk)
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if (ce)
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if (ce)
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casez({anbInf9,aNan9,bNan9,xinf9})
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casez({anbInf9,aNan9,bNan9,xinf9})
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4'b1???: mo <= {1'b0,op9,{FMSB-1{1'b0}},op9,{FMSB{1'b0}}}; // inf +/- inf - generate QNaN on subtract, inf on add
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4'b1???: mo <= {1'b0,op9,{FMSB-1{1'b0}},op9,{FMSB{1'b0}}}; // inf +/- inf - generate QNaN on subtract, inf on add
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4'b01??: mo <= {1'b1,1'b1,fracta9[FMSB-1:0],{FMSB+1{1'b0}}}; // set MSB of Nan to convert to quiet
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4'b01??: mo <= {1'b1,1'b1,fracta9[FMSB-1:0],{FMSB+1{1'b0}}}; // Set MSB of Nan to convert to quiet
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4'b001?: mo <= {1'b1,1'b1,fractb9[FMSB-1:0],{FMSB+1{1'b0}}};
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4'b001?: mo <= {1'b1,1'b1,fractb9[FMSB-1:0],{FMSB+1{1'b0}}};
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4'b0001: mo <= 1'd0; // exponent hit infinity -> force mantissa to zero
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4'b0001: mo <= 1'd0; // exponent hit infinity -> force mantissa to zero
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default: mo <= {mab9,{FMSB-1{1'b0}}}; // mab has an extra lead bit and two trailing bits
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default: mo <= {mab9,{FMSB-1{1'b0}}}; // mab has an extra lead bit and two trailing bits
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endcase
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endcase
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wire [EX:0] o1;
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wire [EX:0] o1;
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wire [MSB+3:0] fpn0;
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wire [MSB+3:0] fpn0;
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fpAddsub #(FPWID) u1 (clk, ce, rm, op, a, b, o1);
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fpAddsub #(FPWID) u1 (clk, ce, rm, op, a, b, o1);
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fpNormalize #(FPWID) u2(.clk(clk), .ce(ce), .under(1'b0), .i(o1), .o(fpn0) );
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fpNormalize #(FPWID) u2(.clk(clk), .ce(ce), .under_i(1'b0), .i(o1), .o(fpn0) );
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fpRound #(FPWID) u3(.clk(clk), .ce(ce), .rm(rm), .i(fpn0), .o(o) );
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fpRound #(FPWID) u3(.clk(clk), .ce(ce), .rm(rm), .i(fpn0), .o(o) );
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endmodule
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endmodule
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No newline at end of file
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No newline at end of file
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