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abt micrprocessor..

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Nigel Goodwin

Super Moderator
Most Helpful Member
itsallabtamrit said:
how many basic instruction is there in 8085 microprocessor..?and how many more we can write from those basic ones..?

Use google and download the datasheet - the instruction will all be in that, and you can make pretty well unlimited programs using them.
 

phalanx

Member
This is screaming homework assignment.

If you want to get technical about it, you can't make any more instructions out of the base ones because they are fixed in hardware. Combinations of instructions are better known as "programs" for which there is some finite limit (granted the limit is astronomically large) which depends on the number of instructions and the amount of program memory the system has.
 

itsallabtamrit

New Member
abt being lazy..no way..there r 74 basic instruction in 8085 mp..and 246 more instruction can be made..because intel at that time in 1973 gave only that much...but we can make 2^8=256 instructions..so which r the rest 10 of them...i thought instead of searching in google i can post it here..may be some senior member can say this..
but i saw u only know to blame..
i was expecting some good answers...
now if u hv a little shame plz tell me those 10 instructions...
 

Papabravo

Well-Known Member
The reason we think you are a student is that there is very little commercial or professional interest in a processor that is thirty years old, built on obsolete technology. But I digress.

Truly your arithmetic escapes me. Nevertheless your question makes certain assumptions which may or may not be true.

The first one is that every possible instruction does something. In particular there may be holes in the opcode(instruction) decode which result in undefined or undocumented instructions. I seem to remember a group of folks that investigated this issue. In most cases the unimplemented instructions were benign. Many processors have unimplemented instruction traps, but the 8085 is not one of them.

The second assumption is that opcodes(instructions) are limited to a single byte. Instructions can be one byte, two bytes, or three bytes long so your method of counting may need to reflect this. When the Z80 was invented they extended the opcode space by allowing four byte instructions so again the space available for opcodes(instructions) expanded, but it is sparsely populated.

If you are not a student please tell us why you are so interested in such ancient and obsolete technology.
 

itsallabtamrit

New Member
obviously i m a student..but sometimes u can get surprising answers for an old thing..sill some ppl work on newtons law..isnt it..then y shud we...i read in paper that some ppl challenge newton's gravitational law...so we can still know abt a processor whch is 30 yrs old...for a electronic freak it never matters the age of any gizmo..i wnted to intract with senior members and get their ideas...i'm interested in embedded systems so in mp..
 

Papabravo

Well-Known Member
I'm not sure I believe that people are still working on Newton's Law, but nevermind that. I'd like to encourage you to abandon cell phone and instant messaging shorthand. It is much easier to communicate your ideas when you use complete sentences with grammar, spelling, and punctuation that is as good as you can possibly manage. I understand that English may not be your first language, but many non-native speakers go to great lengths to improve their skills and I encourage you to do the same.

The stream of conciousness style of your original posts is extremely difficult to read, parse, and understand.
 

Parnelli

New Member
Well said Papabravo. We live in such an "in a hurry" world, and I fear that we are loosing our ability to communicate effectively. As for the 8085 itsallabtamrit, you would need a dumpsterload of them to perfrom the tasks of todays processors, which can be obtained for a reasonable price. If it's a technical history class project, I understand. Do your homework @ intel archives and remember that the longest distance between 2 points is a shortcut.........
 

evandude

New Member
itsallabtamrit said:
sill some ppl work on newtons law..isnt it..then y shud we...i read in paper that some ppl challenge newton's gravitational law...so we can still know abt a processor whch is 30 yrs old...

somehow I don't think research into the opcodes of a long-obsolete microprocessor quite compares to additional research on the laws of physics.

with that aside, your time is yours to use as you see fit, even if others perceive it as a waste. However, as papabravo pointed out, what makes you so certain that there actually have to be 10 additional instructions? and if they're undocumented, why are you so certain that someone on this forum must know them? you act like we are deliberately withholding information of these "super secret ninja opcodes" from you, but you seem to refuse to believe that they may simply not exist.
 

philba

New Member
lol. he didn't give the secret code phrase.

by the way, the intel chip did have some undocumented op codes. and I'm sure some one figured them out long ago and maybe even published them. I vaguely recall that happening. but that is the extent of my memory of a chip that I worked hard to avoid. Plus, with that kind of attitude (and IM english), why would anyone want to help?
 
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