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31 lines
996 B
Systemverilog
Executable File
31 lines
996 B
Systemverilog
Executable File
//performs the fsgnj/fsgnjn/fsgnjx RISCV instructions
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module fsgn (
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input logic [63:0] SrcXE, SrcYE,
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input logic [1:0] SgnOpCodeE,
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output logic [63:0] SgnResE,
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output logic SgnNVE);
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logic AonesExp;
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//op code designation:
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//
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//00 - fsgnj - directly copy over sign value of SrcYE
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//01 - fsgnjn - negate sign value of SrcYE
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//10 - fsgnjx - XOR sign values of SrcXE & SrcYE
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//
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assign SgnResE[63] = SgnOpCodeE[1] ? (SrcXE[63] ^ SrcYE[63]) : (SrcYE[63] ^ SgnOpCodeE[0]);
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assign SgnResE[62:0] = SrcXE[62:0];
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//If the exponent is all ones, then the value is either Inf or NaN,
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//both of which will produce a QNaN/SNaN value of some sort. This will
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//set the invalid flag high.
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assign AonesExp = SrcXE[62]&SrcXE[61]&SrcXE[60]&SrcXE[59]&SrcXE[58]&SrcXE[57]&SrcXE[56]&SrcXE[55]&SrcXE[54]&SrcXE[53]&SrcXE[52];
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//the only flag that can occur during this operation is invalid
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//due to changing sign on already existing NaN
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assign SgnNVE = AonesExp & SgnResE[63];
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endmodule
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