| Line 78... |
Line 78... |
reg [5:0] count = 'd0;
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reg [5:0] count = 'd0;
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reg [5:0] count_nxt;
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reg [5:0] count_nxt;
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reg [67:0] product = 'd0;
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reg [67:0] product = 'd0;
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reg [67:0] product_nxt;
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reg [67:0] product_nxt;
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reg [1:0] flags_nxt;
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reg [1:0] flags_nxt;
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reg sum_acc1_carry = 'd0;
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reg sum_acc1_carry_nxt;
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wire [32:0] sum_acc1; // the MSB is the carry out for the upper 32 bit addition
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wire [32:0] sum_acc1; // the MSB is the carry out for the upper 32 bit addition
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assign enable = i_function[0];
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assign enable = i_function[0];
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assign accumulate = i_function[1];
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assign accumulate = i_function[1];
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| Line 152... |
Line 150... |
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always @*
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always @*
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begin
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begin
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// Defaults
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// Defaults
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count_nxt = count;
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count_nxt = count;
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sum_acc1_carry_nxt = sum_acc1_carry;
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product_nxt = product;
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product_nxt = product;
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// update Negative and Zero flags
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// update Negative and Zero flags
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// Use registered value of product so this adds an extra cycle
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// Use registered value of product so this adds an extra cycle
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// but this avoids having the 64-bit zero comparator on the
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// but this avoids having the 64-bit zero comparator on the
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| Line 171... |
Line 168... |
else if ( count == 6'd34 && accumulate )
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else if ( count == 6'd34 && accumulate )
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begin
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begin
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// Note that bit 0 is not part of the product. It is used during the booth
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// Note that bit 0 is not part of the product. It is used during the booth
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// multiplication algorithm
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// multiplication algorithm
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product_nxt = { product[64:33], sum_acc1[31:0], 1'd0}; // Accumulate
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product_nxt = { product[64:33], sum_acc1[31:0], 1'd0}; // Accumulate
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sum_acc1_carry_nxt = sum_acc1[32];
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end
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end
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// Multiplication state counter
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// Multiplication state counter
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if (count == 6'd0) // start
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if (count == 6'd0) // start
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count_nxt = enable ? 6'd1 : 6'd0;
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count_nxt = enable ? 6'd1 : 6'd0;
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| Line 190... |
Line 186... |
always @ ( posedge i_clk )
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always @ ( posedge i_clk )
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if ( !i_fetch_stall )
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if ( !i_fetch_stall )
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begin
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begin
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count <= i_execute ? count_nxt : count;
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count <= i_execute ? count_nxt : count;
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product <= i_execute ? product_nxt : product;
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product <= i_execute ? product_nxt : product;
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sum_acc1_carry <= i_execute ? sum_acc1_carry_nxt : sum_acc1_carry;
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o_done <= i_execute ? count == 6'd31 : o_done;
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o_done <= i_execute ? count == 6'd31 : o_done;
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end
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end
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// Outputs
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// Outputs
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assign o_out = product[32:1];
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assign o_out = product[32:1];
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