[Vm-dev] Re: localIP, instructionPointer, currentBytecode data size

Hi, Thank you so much for your detail explanation.

I saw the following in win32 VM interp.c,

# define pointerForOop(oop) ((char *)(sqMemoryBase + ((usqInt)(oop))))

...

char* localSP; char* localIP; sqInt currentBytecode;

browserPluginInitialiseIfNeeded(); /* begin internalizeIPandSP */ localIP = pointerForOop(instructionPointer); //foo->instructionPointer localSP = pointerForOop(stackPointer);

Is it true that char* in bold explain difference in both version? localIP = pointerForOop(instructionPointer); instead of localIP = pointerForOop(foo->instructionPointer);

In the bluebook, for example

pushReceiverVariableBytecode | fieldIndex | fieldIndex := self extractBits: 12 to: 15 of: currentBytecode.

I thought bytecode should be one byte, 8 bits. Why extracting from the second byte?

Thanks.

Ang Beepeng