Pascal not considered harmful - was Re: Rich kids are into COBOL

On 02/21/2015 02:38 AM, Sean Conner wrote: You miss my point, I think. I'll try again. Consider a machine with a word length of 64 bits. This machine represents floating point numbers with a 16 bit exponent and a 48 bit mantissa (nothing unusual so far). So we have the length of short = int = long = 64 bits. So far so good. However, given such a generous word length, the designers of this machine decide not to dedicate special hardware toward handling 64 bit integers, but have said that 48 bits should be long enough for anyone, and so treat integer arithmetic as a subset of floating point (straightforward enough). So not all values of a 64 bit word reflect valid integers--the exponent must be a certain value--anything else is floating point. Now, here's where we get into sticky territory. Since C draws no data type distinctions between bitwise logical operations on ints and arithmetic operations, is it possible to implement C on this machine? It should be obvious that bitwise logical operations on a 64 bit int, whose upper 16 bits must conform to a special case of a float, that all logical operations on an int do not result in legal int values. ------------------- As far as "bytes" on systems, perhaps the attribute of byte addressability makes sense on short word-length machines, but I don't believe that it's necessary for longer word length machines. A decent set of shifting and masking primitives operating on whole words has been known to work as well, and in some cases better than a machine that dedicates hardware toward addressing sub-word-length items. I think byte addressing is more a matter of functional fixedness more than anything else. --Chuck