Smalltalk.org™ Reinvention
Evan Hildreth
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Description: A blog about programming, technology and society.
We don’t always think of it this way, but on modern machines, memory and pointers are an abstraction. Today’s machines have virtual memory, divided in blocks called “pages”, such that the addresses represented by pointers don’t necessarily map to the same address in physical RAM. In fact, mmap even makes it possible to map files to memory, so some of these addresses aren’t even mapped to RAM addresses at all.
Two weeks ago, I wrote about UVM , the small virtual machine I’ve been building in my spare time. This VM has a relatively low-level design where it has untyped instructions and pointers for instance. Generally speaking, I’ve done my best to design the VM to be fairly “conventional”, in the sense that most design elements are aligned with common practice and unsurprising. In my opinion, this is important because it keeps the design approachable to newcomers. Having a design that’s unsurprising means that ne
Even though I’ve done what I could to keep the design of UVM unsurprising, there is one aspect that’s unconventional. At the moment, UVM uses what’s known as a Harvard Architecture , where code and data live in two separate linear address spaces. Essentially, code and data live in two separate arrays of bytes. There’s actually a third address space too: the stack is distinct from the address space used for the heap. That means you can’t directly get a pointer to something that’s stored on the stack.
Smalltalk.org™ Reinvention
Evan Hildreth
HN – Top Stories
whnex - top
Index
Hacker News