Linked by Thom Holwerda on Sun 8th Jul 2012 22:54 UTC
General Development "In this tiny ebook I'm going to show you how to get started writing 6502 assembly language. [...] I think it's valuable to have an understanding of assembly language. Assembly language is the lowest level of abstraction in computers - the point at which the code is still readable. Assembly language translates directly to the bytes that are executed by your computer's processor. If you understand how it works, you've basically become a computer magician." More of this, please.
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RE[6]: Comment by ilovebeer
by Alfman on Tue 10th Jul 2012 21:41 UTC in reply to "RE[5]: Comment by ilovebeer"
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"Fixed that for ya!"
"If you ain't in cache, you ain't nothin."

Actually, I may be using poor semantics, but I consider memory limited processes (whether from CPU or GPU) to be "IO" bound. After all, those requests have to be serialised over the system bus almost like any other IO. Obviously most programmers treat "memory" as though it's different from IO. While memory IO clearly plays a specific role for the CPU, from a databus-oriented point of view it's not all that special.

Semantics aside, it can be difficult to make SMP systems scale well if memory & IO are the real bottlenecks. I'd consider a CPU-bound process one that makes minimal use of the system bus, including system memory. I find many multithreaded advocates proposing to subdivide problems among tiny light weight threads, but very often they shift a problem from being CPU-bound (which is good for SMP) into one that is memory-bound which offsets the benefits of parallelism.

Even caching is problematic in that x86 processors must implement very strict cache coherency models, which severely limits SMP scalability.

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