[Vm-dev] Re: CArray arithmetic methods...

On Sat, Oct 9, 2010 at 3:01 PM, Eliot Miranda eliot.miranda@gmail.comwrote:

Hi All,

now I'm successfully simulating the LargeIntegers plugin I'm hitting

what I consider a bug in CArray, used to model C pointers in the simulator. The first problem is that CArray>>#+ & #- return an integer value, not another CArray, (in C (char *)(exp) + n is still of type (char *), not int) and that the addition/subtraction doesn't scale by the unit size (in C (type *)p + n == (type *)((char *)p + n * sizeof(type))). The second problem is that << >> * & // are meaningless on C pointers. Anyone think of a good reason why I shouldn't a) rewrite CArray>>#+ & #- to read

• n

^ self shallowCopy += (n * unitSize)

• n

^ self shallowCopy -= (n * unitSize)

(since e.g. += increment

ptrOffset := ptrOffset + increment)

and b) delete CArray>>#*, #//, #<<, #>>, #bitAnd:, #bitOr:, #bitShift: & #signedBitShift: ?

So far so good. The only thing that broke was the use of BitBltSimulator/BitBltSimulation>>#tableLookup:at: which can be deleted and in BitBltSimulation>>#pickSourcePixels:flags:srcMask:destMask:srcShiftInc:dstShiftInc: rewrite destPix := self tableLookup: cmLookupTable at: (sourcePix bitAnd: cmMask). to destPix := cmLookupTable at: (sourcePix bitAnd: cmMask).

best Eliot