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Merge pull request #3 from jrtc27/overflow

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Avoid shift amount overflow in maskAddr
This commit is contained in:
PeterRugg
2020-02-12 00:22:50 +00:00
committed by GitHub
parent 8f111b64fe 5834111524
commit ce8e442ba6
1 changed files with 2 additions and 1 deletions
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3
CHERICC_Fat.bsv
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@@ -1021,8 +1021,9 @@ instance CHERICap #(CapReg, OTypeW, FlagsW, CapAddressW, CapW, TSub#(MW, 3));
function CapReg maskAddr (CapReg cap, Bit#(TSub#(MW, 3)) mask);
cap.address[valueOf(TSub#(MW, 4)):0] = cap.address[valueOf(TSub#(MW, 4)):0] & mask;
UInt#(TAdd#(ExpW,1)) expExt = zeroExtend(cap.bounds.exp);
//Update addrBits. Since exp can be up to 64, extend to 64 + 8 bits so bit-select is always in range
cap.addrBits = (({40'b0,cap.address})[cap.bounds.exp+fromInteger(valueOf(TSub#(MW,1))):cap.bounds.exp]); //TODO avoid shift?
cap.addrBits = (({40'b0,cap.address})[expExt+fromInteger(valueOf(TSub#(MW,1))):expExt]); //TODO avoid shift?
return cap;
endfunction