Cheri-research/cheri-cap-lib
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Move getLength to address length (not address length + 1), as we're explicitly saturating in order to express as a normal address.

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This commit is contained in:
Jonathan Woodruff
2025-02-04 16:31:01 +00:00
parent 3926b793bf
commit b3896e4e50
3 changed files with 6 additions and 6 deletions
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6
CHERICC_Fat.bsv
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@@ -346,7 +346,7 @@ function BoundsInfo#(CapAddrW) getBoundsInfoFat (CapFat cap, TempFields tf)
Bit #(TAdd #(MW, 2)) correctTop = {pack (tf.topCorrection), topBits};
// Get the length by subtracting base from top and shifting appropriately, and
// saturate in case of big exponent
CapAddrPlus1 length =
CapAddr length =
(exp >= resetExp) ? ~0 : zeroExtend (correctTop - correctBase) << exp;
// compute repBase
@@ -437,12 +437,12 @@ function CapAddrPlus1 getTopFat(CapFat cap, TempFields tf);
ret[valueOf(CapAddrW)] = ~ret[valueOf(CapAddrW)];
return ret;
endfunction
function CapAddrPlus1 getLengthFat(CapFat cap, TempFields tf);
function CapAddr getLengthFat(CapFat cap, TempFields tf);
// Get the top and base bits with the 2 correction bits prepended
Bit#(TAdd#(MW,2)) top = {pack(tf.topCorrection),cap.bounds.topBits};
Bit#(TAdd#(MW,2)) base = {pack(tf.baseCorrection),cap.bounds.baseBits};
// Get the length by substracting base from top and shifting appropriately
CapAddrPlus1 length = zeroExtend(top - base) << cap.bounds.exp;
CapAddr length = zeroExtend(top - base) << cap.bounds.exp;
// Return a saturated length in case of big exponent
// TODO: The saturation behaviour here is short of being correct
return (cap.bounds.exp >= resetExp) ? ~0 : length;

4
CHERICap.bsv
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@@ -80,7 +80,7 @@ typedef union tagged {
typedef struct {
Bit #(addrW) base;
Bit #(TAdd #(addrW, 1)) top;
Bit #(TAdd #(addrW, 1)) length;
Bit #(addrW) length;
Bit #(addrW) repBase;
Bit #(TAdd #(addrW, 1)) repTop;
Bit #(TAdd #(addrW, 1)) repLength;
@@ -258,7 +258,7 @@ typeclass CHERICap #( type capT // type of the CHERICap capability
// Get the top
function Bit #(TAdd #(addrW, 1)) getTop (capT cap) = getBoundsInfo(cap).top;
// Get the length
function Bit #(TAdd #(addrW, 1)) getLength (capT cap) =
function Bit #(addrW) getLength (capT cap) =
getBoundsInfo(cap).length;
// Assertion that the capability's address is between its base and top
function Bool isInBounds (capT cap, Bool isTopIncluded) =

2
CHERICapWrap.bsv
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@@ -88,7 +88,7 @@ function Bit#(CapAddrW) `W(getBase) (`CAPTYPE cap) = getBase(capArg(cap));
(* noinline *)
function Bit#(TAdd#(CapAddrW, 1)) `W(getTop) (`CAPTYPE cap) = getTop(capArg(cap));
(* noinline *)
function Bit#(TAdd#(CapAddrW, 1)) `W(getLength) (`CAPTYPE cap) = getLength(capArg(cap));
function Bit#(CapAddrW) `W(getLength) (`CAPTYPE cap) = getLength(capArg(cap));
(* noinline *)
function Bool `W(isInBounds) (`CAPTYPE cap, Bool isTopIncluded) = isInBounds(capArg(cap), isTopIncluded);
(* noinline *)