On older machines, codes smaller than 8 bits were fairly common, but most of those have been dead and gone for years now. C and C++ have mandated a minimum of 8 bits for char, at least as far back as the C89 standard. [Edit: For example, C90, ยง5.2.4.2.1 requires CHAR_BIT >= 8 and UCHAR_MAX … Read more
The theory: Let’s start from this: nowaday’s CPU’s are superscalar, which means that they can execute more than one instruction per cycle (IPC). Latest Intel architectures can go up to 4 IPC (4 x86 instruction decoders). Let’s not bring macro / micro fusion into discussion to complicate things more :). Typically, workloads do not reach … Read more
There are a few attributes of a stack-based VM that fit in well with Java’s design goals: A stack-based design makes very few assumptions about the target hardware (registers, CPU features), so it’s easy to implement a VM on a wide variety of hardware. Since the operands for instructions are largely implicit, the object code … Read more