21–30 of 175 posts
Sadly we have strayed to the other extreme. From "every instruction is precious" right over to, "who cares how many instructions I use?" Nowadays, desktop apps which started in an instant 20 years ago, seem to take several seconds even before they are even doing anything useful like loading a project or whatever. Even things like Visual Studio looking through the MRU project list can take 10 seconds (probably a threa…
Bonus trivia: those "Raw, unadorned, inscrutable hexadecimal numbers"? Those would not have been the 0-9a-f we're familiar with today, but 0-9fgjkqw[1]! [1]: http://ed-thelen.org/comp-hist/lgp-30-man.html#R4.13
Bonus trivia: those "Raw, unadorned, inscrutable hexadecimal numbers"? Those would not have been the 0-9a-f we're familiar with today, but 0-9fgjkqw[1]! [1]: http://ed-thelen.org/comp-hist/lgp-30-man.html#R4.13
Bonus trivia: those "Raw, unadorned, inscrutable hexadecimal numbers"? Those would not have been the 0-9a-f we're familiar with today, but 0-9fgjkqw[1]! [1]: http://ed-thelen.org/comp-hist/lgp-30-man.html#R4.13
I'm disgusted... What was the motivation for that?
[0] http://laboratorium.net/archive/2008/04/28/a_few_facts_about...
Bonus trivia: those "Raw, unadorned, inscrutable hexadecimal numbers"? Those would not have been the 0-9a-f we're familiar with today, but 0-9fgjkqw[1]! [1]: http://ed-thelen.org/comp-hist/lgp-30-man.html#R4.13
I've never heard of this. Was this just a quirk of the LGP-30?
Can some way more experienced than me ELI5 why the inner loop part was so clever? I'm the most novice of programmers and have never touch anything remotely like pointers so feel I am missing the lightbulb moment the author clearly got. Many thanks.
From the wikipedia article: Eventually he realized that Kaye was using self-modifying code to process elements of an array, and had coded the loop in such a way as to take advantage of an overflow. Adding 1 to the address field of an instruction that referred to address x normally just changed the address to x+1. But when x was already the highest possible address, not only did the address wrap around to 0, but a 1 w…
Very reminisce of the 6502 "issue" of jumping with an address on a page boundary.
Per Wikipedia:
the processor will not jump to the address stored in xxFF and xxFF+1 as expected, but rather the one defined by xxFF and xx00 (for example, JMP ($10FF) would jump to the address stored in 10FF and 1000, instead of the one stored in 10FF and 1100). This defect continued through the entire NMOS line, but was corrected in the CMOS derivatives.
I still think, that this is the most efficient way to teach kids CPU/Memory and assembler.