On 10/19/2010 2:53 PM, john gilmore wrote:
Perhaps even more puzzling is the notion of "enforcing that unassigned bits in instructions [be] zero". The assembler sets these bits to zero in such instructions; one must use instruction punning to set them otherwise. How can one guard against such misguided schemes (without crippling the assembler)? Or again, there may be other issues here that I have missed. If so, I should be grateful to know what they are.
The unexpected consequence of executing on a lower level processor a program targeted for a higher level processor, or even testing, with success on the lower level processor a program which somehow sets those bits and fails on the higher processor where those bits take effect. I suspect this is an invitation for you to get on your soapbox and tout the value of conditional assembly to target specific hardware. Providers who deliver object programs to a wide audience of users haven't that luxury, and the users may take unkindly to "Some assembly required." -- gil
