OK, so I had to look.

It's like they saw the two main camps (same line vs next line) and said "let's come up with something everyone will hate":

    TInt GetROMSize(TInt /*aDeviceNumber*/, TInt /*aAttrib*/, TBool /*aSet*/, TAny* aInOut)
        {
        TMemoryInfoV1 info;
        TPckg<TMemoryInfoV1> infoPckg(info);
        TInt r=UserSvr::HalFunction(EHalGroupKernel, EKernelHalMemoryInfo, (TAny*)&infoPckg, NULL);
        if (r==KErrNone)
            {
            *(TInt*)aInOut=info.iTotalRomInBytes;
            }
        return r;
        }