(Untitled)

Jan 20, 2012 04:28

Long, long ago, probably somewhere near 2004, I came across a some site describing, among other things, personal system of symbolism based on the ascii chart. I suspect the link to it was posted here, so I checked the whole 2004 archive, but to no avail. Still, if any of old-timers here remember something similar, I would be glad to know :)

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effrenata January 23 2012, 05:44:29 UTC
Heh, synchronicity. Sorry, I don't have the answer to this, but was going to ask s/t similar:

Does anyone know the binary machine code for: MOV Ax,Bx

I seem to recall from a course I took yrs. back it was "01000111". However,this is machine-dependent, so what is current in use on most systems may have changed.

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mindszenty January 23 2012, 10:37:19 UTC
No, it's not machine-dependent, but architecture-dependent. So on all x86 machines, for instance, for all these years MOV AX, BX was coded the same: 89D8 hexadecimal (or binary 10001001 11011000) - or else old programs should be recompiled or even rewritten for each new machine. But machines based on the different architecture - say, on iPhones, which are ARM-compatible - use different instruction set and different machine codes, and some may even not have instruction comparable to "MOV AX, BX". I don't know which one encode it as 01000111, though :)

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effrenata January 23 2012, 22:26:26 UTC
It's 8-bit, so evidently an old one. I remember that bit of code from a course I took back in the late 80's/early 90's. I liked the symbol "01000111" b/c of its symmetry & archetypal quality; in my paradigm, referring to the basic process by which one thing replaces or supersedes another.

I wish I'd saved my old CS books. There's probably a reference to this code somewhere on the net, since there are hobbyists around who like to keep & use outmoded systems.

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mindszenty January 23 2012, 23:39:33 UTC
Okay, I found this. That's opcode for 'MOV B, A' on Altair 8800 processor. Very interesting machine in itself, it turns out: http://en.wikipedia.org/wiki/Altair_8800

Once I used machine codes as symbols, too :) I still remember 0xCD as beginning of opcode for interrupt in 0x86, and that was a symbol of accessing powerful library functions for me.

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