forked from Github_Repos/cvw
62 lines
2.7 KiB
Systemverilog
62 lines
2.7 KiB
Systemverilog
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// This module takes as inputs two operands (op1 and op2)
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// the operation type (op_type) and the result precision (P).
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// Based on the operation and precision , it conditionally
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// converts single precision values to double precision values
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// and modifies the sign of op1. The converted operands are Float1
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// and Float2.
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module convert_inputs(Float1, Float2, op1, op2, op_type, P);
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input [63:0] op1; // 1st input operand (A)
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input [63:0] op2; // 2nd input operand (B)
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input [3:0] op_type; // Function opcode
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input P; // Result Precision (0 for double, 1 for single)
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output [63:0] Float1; // Converted 1st input operand
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output [63:0] Float2; // Converted 2nd input operand
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wire conv_SP; // Convert from SP to DP
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wire negate; // Operation is negation
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wire abs_val; // Operation is absolute value
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wire Zexp1; // One if the exponent of op1 is zero
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wire Zexp2; // One if the exponent of op2 is zero
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wire Oexp1; // One if the exponent of op1 is all ones
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wire Oexp2; // One if the exponent of op2 is all ones
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// Convert from single precision to double precision if (op_type is 11X
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// and P is 0) or (op_type is not 11X and P is one).
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assign conv_SP = (op_type[2]&op_type[1]) ^ P;
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// Test if the input exponent is zero, because if it is then the
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// exponent of the converted number should be zero.
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assign Zexp1 = ~(op1[62] | op1[61] | op1[60] | op1[59] |
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op1[58] | op1[57] | op1[56] | op1[55]);
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assign Zexp2 = ~(op2[62] | op2[61] | op2[60] | op2[59] |
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op2[58] | op2[57] | op2[56] | op2[55]);
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assign Oexp1 = (op1[62] & op1[61] & op1[60] & op1[59] &
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op1[58] & op1[57] & op1[56] & op1[55]);
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assign Oexp2 = (op2[62] & op2[61] & op2[60] & op2[59] &
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op2[58] & op2[57] & op2[56] &op2[55]);
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// Conditionally convert op1. Lower 29 bits are zero for single precision.
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assign Float1[62:29] = conv_SP ? {op1[62], {3{(~op1[62]&~Zexp1)|Oexp1}}, op1[61:32]}
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: op1[62:29];
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assign Float1[28:0] = op1[28:0] & {29{~conv_SP}};
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// Conditionally convert op2. Lower 29 bits are zero for single precision.
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assign Float2[62:29] = conv_SP ? {op2[62],
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{3{(~op2[62]&~Zexp2)|Oexp2}}, op2[61:32]}
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: op2[62:29];
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assign Float2[28:0] = op2[28:0] & {29{~conv_SP}};
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// Set the sign of Float1 based on its original sign and if the operation
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// is negation (op_type = 101) or absolute value (op_type = 100)
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assign negate = op_type[2] & ~op_type[1] & op_type[0];
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assign abs_val = op_type[2] & ~op_type[1] & ~op_type[0];
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assign Float1[63] = (op1[63] ^ negate) & ~abs_val;
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assign Float2[63] = op2[63];
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endmodule // convert_inputs
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