I'm not sure why noteAsRoot:headerLoc: uses a red zone. Why can't it just not update the root table? The root table is only used for incremental GCs and they will perform a full GC if the root table has overflowed?

I'm asking because I had a bug in Exupery's version of this which I fixed by setting allocationCount on root table overflow. This appears to work but is there a good reason for the logic that the interpreter uses now?

Bryce

P.S. The method is: noteAsRoot: oop headerLoc: headerLoc "Record that the given oop in the old object area points to an object in the young area. HeaderLoc is usually = oop, but may be an addr in a forwarding block." | header | self inline: true. header := self longAt: headerLoc. (header bitAnd: RootBit) = 0 ifTrue: ["record oop as root only if not already recorded" rootTableCount < RootTableRedZone ifTrue: ["record root if there is enough room in the roots table " rootTableCount := rootTableCount + 1. rootTable at: rootTableCount put: oop. self longAt: headerLoc put: (header bitOr: RootBit)] ifFalse: ["we're getting in the red zone" rootTableCount < RootTableSize ifTrue: ["but there's still space to record it" rootTableCount := rootTableCount + 1. rootTable at: rootTableCount put: oop. self longAt: headerLoc put: (header bitOr: RootBit). "but force an IGC on the next allocation" allocationCount := allocationsBetweenGCs + 1]]]