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Fixed issue 250. instruction classification was not correct for jalr ra (non zero).

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This commit is contained in:
Rose Thompson 2023-10-23 15:30:43 -05:00
parent 2aecf688f9
commit 1611d5ec3c
1 changed files with 8 additions and 8 deletions
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16
src/ifu/bpred/icpred.sv
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@ -51,20 +51,20 @@ module icpred import cvw::*; #(parameter cvw_t P,
// An alternative to using the BTB to store the instruction class is to partially decode
// the instructions in the Fetch stage into, Call, Return, Jump, and Branch instructions.
// This logic is not described in the text book as of 23 February 2023.
logic ccall, cj, cjr, ccallr, CJumpF, CBranchF;
logic cjal, cj, cjr, cjalr, CJumpF, CBranchF;
logic NCJumpF, NCBranchF;
if(P.C_SUPPORTED) begin
logic [4:0] CompressedOpcF;
assign CompressedOpcF = {PostSpillInstrRawF[1:0], PostSpillInstrRawF[15:13]};
assign ccall = CompressedOpcF == 5'h09 & P.XLEN == 32;
assign cjal = CompressedOpcF == 5'h09 & P.XLEN == 32;
assign cj = CompressedOpcF == 5'h0d;
assign cjr = CompressedOpcF == 5'h14 & ~PostSpillInstrRawF[12] & PostSpillInstrRawF[6:2] == 5'b0 & PostSpillInstrRawF[11:7] != 5'b0;
assign ccallr = CompressedOpcF == 5'h14 & PostSpillInstrRawF[12] & PostSpillInstrRawF[6:2] == 5'b0 & PostSpillInstrRawF[11:7] != 5'b0;
assign CJumpF = ccall | cj | cjr | ccallr;
assign cjalr = CompressedOpcF == 5'h14 & PostSpillInstrRawF[12] & PostSpillInstrRawF[6:2] == 5'b0 & PostSpillInstrRawF[11:7] != 5'b0;
assign CJumpF = cjal | cj | cjr | cjalr;
assign CBranchF = CompressedOpcF[4:1] == 4'h7;
end else begin
assign {ccall, cj, cjr, ccallr, CJumpF, CBranchF} = '0;
assign {cjal, cj, cjr, cjalr, CJumpF, CBranchF} = '0;
end
assign NCJumpF = PostSpillInstrRawF[6:0] == 7'h67 | PostSpillInstrRawF[6:0] == 7'h6F;
@ -72,11 +72,11 @@ module icpred import cvw::*; #(parameter cvw_t P,
assign BPBranchF = NCBranchF | (P.C_SUPPORTED & CBranchF);
assign BPJumpF = NCJumpF | (P.C_SUPPORTED & (CJumpF));
assign BPReturnF = (NCJumpF & (PostSpillInstrRawF[19:15] & 5'h1B) == 5'h01) | // returnurn must returnurn to ra or r5
(P.C_SUPPORTED & (ccallr | cjr) & ((PostSpillInstrRawF[11:7] & 5'h1B) == 5'h01));
assign BPReturnF = (NCJumpF & (PostSpillInstrRawF[19:15] & 5'h1B) == 5'h01 & PostSpillInstrRawF[11:7] == 5'b0) | // return must return to ra or r5
(P.C_SUPPORTED & cjr & ((PostSpillInstrRawF[11:7] & 5'h1B) == 5'h01));
assign BPCallF = (NCJumpF & (PostSpillInstrRawF[11:07] & 5'h1B) == 5'h01) | // call(r) must link to ra or x5
(P.C_SUPPORTED & (ccall | (ccallr & (PostSpillInstrRawF[11:7] & 5'h1b) == 5'h01)));
(P.C_SUPPORTED & (cjal | (cjalr & (PostSpillInstrRawF[11:7] & 5'h1b) == 5'h01)));
end else begin
// This section connects the BTB's instruction class prediction.