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Make setOffset precise.

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jon
2020-06-03 11:09:19 +01:00
parent 88bcd6b487
commit 81f5025366
1 changed files with 4 additions and 2 deletions
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6
CHERICC_Fat.bsv
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@@ -623,15 +623,17 @@ function VnD#(CapFat) incOffsetFat(CapFat cap, LCapAddress pointer, Bit#(CapAddr
// Select the appropriate toBounds value
Bit#(MW) toBounds = (setOffset) ? toBounds_A : toBounds_B;
Bit#(MW) toBoundsM1 = (setOffset) ? toBoundsM1_A : toBoundsM1_B;
Bool addrAtRepBound = !setOffset && (repBoundBits == cap.addrBits);
// Implement the inLimit test
Bool inLimits = False;
if (posInc) begin
// For a positive or null increment
inLimits = offsetBits < toBoundsM1;
// SetOffset is offsetting against base, which has 0 in the lower bits, so we don't need to be conservative.
inLimits = (setOffset) ? offsetBits <= toBoundsM1 : offsetBits < toBoundsM1;
end else begin
// For a negative increment
inLimits = (offsetBits >= toBounds) && (repBoundBits != cap.addrBits);
inLimits = (offsetBits >= toBounds) && !addrAtRepBound;
end
// Complete representable bounds check