Cheri-research/cheri-cap-lib
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Avoid shift amount overflow in maskAddr

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This commit is contained in:
James Clarke
2020-02-11 22:46:07 +00:00
parent 8f111b64fe
commit 5834111524
1 changed files with 2 additions and 1 deletions
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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