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Fold in discussions with Jon and Matt regarding split representable regions

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gameboo
2021-10-07 15:17:13 +01:00
parent aa0a8fe224
commit bc727f9731
2 changed files with 33 additions and 9 deletions
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16
CHERICap.bsv
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@@ -84,6 +84,7 @@ typedef struct {
Bit #(addrW) repBase;
Bit #(TAdd #(addrW, 1)) repTop;
Bit #(TAdd #(addrW, 1)) repLength;
Bool repSplit;
} BoundsInfo #(numeric type addrW) deriving (Bits, Eq, FShow);
// helper types and functions
@@ -272,13 +273,18 @@ typeclass CHERICap #( type capT // type of the CHERICap capability
// Get the representable length
function Bit #(TAdd #(addrW, 1)) getRepLength (capT cap) =
getBoundsInfo(cap).repLength;
// Check if the capapbility's representable region is split (i.e. wrapping the
// address space)
function Bool isRepSplit (capT cap) = getBoundsInfo(cap).repSplit;
// Assertion that the capability's address is between its representable
// base and top
function Bool isInRepBounds (capT cap, Bool isRepTopIncluded) =
belongsToRange ( zeroExtend (getAddr (cap))
, zeroExtend (getRepBase (cap))
, getRepTop (cap)
, isRepTopIncluded );
function Bool isInRepBounds (capT cap);
let addr = getAddr (cap);
let bInfo = getBoundsInfo (cap);
let okLo = addr >= bInfo.repBase;
let okHi = zeroExtend (addr) < bInfo.repTop;
return (okLo && okHi) || (bInfo.repSplit && (okLo != okHi));
endfunction
// Check the alignment of the base, giving least significant 2 bits.
function Bit #(2) getBaseAlignment (capT cap) = getBoundsInfo (cap).base[1:0];