On Fri, May 14, 2010 at 02:41:22AM +0300, Igor Stasenko wrote:
> Just want to share my experience working with Interpreter/
> interpreterProxy api using VMMaker.
> 
> Make a guess (and answer quickly, in what direction each of these
> methods doing conversion)
> 
> positive32BitValueOf:
> positive32BitIntegerFor:
> 
> 
> got the answer?
> 
> These methods along with other xxxIntegerFor: and xxxValueOf:
> used most frequently in primitive conversion code.
> And i am really sick of such naming..

If you think of a positive integer value stored in a 32-bit C variable
as a "positive32BitValue", and an integer object representing values
in the range 0 through 4294967295 as a "positive32BitInteger", then
the naming seems reasonable to me.

Personally, I use MemoryAccess and SlangBrowser to look at things
like this in the browser and figure out what is really going on. This
shows that #positive32BitValueOf: answers an integer value (twos complement
32-bit integer as in C or Fortran), and #positive32BitIntegerFor: answers
an object of type SmallInteger or LargePositiveInteger.


/*	Convert the given object into an integer value.
	The object may be either a positive ST integer or a four-byte LargePositiveInteger. */

sqInt positive32BitValueOf(sqInt oop) {
register struct foo * foo = &fum;
    sqInt sz;
    sqInt value;

	if ((oop & 1)) {
		value = (oop >> 1);
		if (value < 0) {
			return primitiveFail();
		}
		return value;
	}
	assertClassOfis(oop, splObj(ClassLargePositiveInteger));
	if (foo->successFlag) {
		sz = lengthOf(oop);
		if (!(sz == 4)) {
			return primitiveFail();
		}
	}
	if (foo->successFlag) {
		return (((fetchByteofObject(0, oop)) + ((fetchByteofObject(1, oop)) << 8)) + ((fetchByteofObject(2, oop)) << 16)) + ((fetchByteofObject(3, oop)) << 24);
	}
}



/*	Note - integerValue is interpreted as POSITIVE, eg, as the result of
		Bitmap>at:, or integer>bitAnd:. */

sqInt positive32BitIntegerFor(sqInt integerValue) {
register struct foo * foo = &fum;
    sqInt newLargeInteger;

	if (integerValue >= 0) {
		if (
# ifdef SQ_HOST32  // cast to int for 64 bit image on 32 bit host
			(((((int) integerValue)) ^ ((((int) integerValue)) << 1)) >= 0)
# else
			((integerValue >= -1073741824) && (integerValue <= 1073741823))
# endif  // SQ_HOST32
		) {
			return ((integerValue << 1) | 1);
		}
	}
	if (BytesPerWord == 4) {

		/* Faster instantiateSmallClass: currently only works with integral word size. */

		newLargeInteger = instantiateSmallClasssizeInBytes(((sqInt) ((((sqInt *) ((sqMemoryBase) + ((foo->specialObjectsOop + BaseHeaderSize) + (ClassLargePositiveInteger << ShiftForWord)))))[0])), BaseHeaderSize + 4);
	} else {

		/* Cant use instantiateSmallClass: due to integral word requirement. */

		newLargeInteger = instantiateClassindexableSize(((sqInt) ((((sqInt *) ((sqMemoryBase) + ((foo->specialObjectsOop + BaseHeaderSize) + (ClassLargePositiveInteger << ShiftForWord)))))[0])), 4);
	}
	((sqInt) ((((unsigned char *) ((sqMemoryBase) + ((newLargeInteger + BaseHeaderSize) + 3))))[0] = ((((usqInt) integerValue) >> 24) & 255)));
	((sqInt) ((((unsigned char *) ((sqMemoryBase) + ((newLargeInteger + BaseHeaderSize) + 2))))[0] = ((((usqInt) integerValue) >> 16) & 255)));
	((sqInt) ((((unsigned char *) ((sqMemoryBase) + ((newLargeInteger + BaseHeaderSize) + 1))))[0] = ((((usqInt) integerValue) >> 8) & 255)));
	((sqInt) ((((unsigned char *) ((sqMemoryBase) + ((newLargeInteger + BaseHeaderSize) + 0))))[0] = (integerValue & 255)));
	return newLargeInteger;
}