My IMSAI (enshrined down in my basement) is immortalized as the teenage hacker's bedroom computer (he uses it to hack into his high school computer and improve his grades) in the movie "War Games."
An unknown chip maker named Intel had developed a complete digital computer on one single chip, the 8008, which quickly evolved into the somewhat more sophisticated 8080.
The problem was, nobody in industry or government wanted it or had a use for it.
But a tiny startup called MITS decided to sell a home computer KIT designed around this unwanted, orphaned chip, and announced their home computer via ads and a big series of Do-It-Yourself articles in Popular Electronics magazine.
This astonishing and wholly unexpected migration of digital computing from Giant Industry & Big Government to the humble cottage spare bedroom happened in 1975. The first home computers, in kit form, were horribly primitive compared to the Dells and Macs you can buy today, and cost about as much as a brand new refrigerator.
For most owners and users of modern computers, what goes on at the deepest level of the computer's guts -- how, exactly, the computer does the jobs we want it to do -- might as well be Magic or Alchemy or Astrology or Witchcraft.
Even those of us who can program a computer in a High-Level Language, like BASIC or FORTRAN or PYTHON or COBOL, are pretty much speaking to the computer in a pretty comprehensible dialect of English. These languages were designed to make programming Human-Friendly.
But the way a computer actually "thinks" and performs tasks is extremely Human-Hostile. At its "core," a digital computer can only manipulate enormously long strings of zeroes and ones, executing operations which are entirely based on Binary Arithmetic and Boolean Algebra.
This is what "thinking" really looks like inside a computer's CPU (Central Processing Unit) chip:
00010110010011001100010101110010011111010100010100100000101010101010 ...
Pathetically, most CPU's can't do any mathematics beyond simple addition of two binary numbers:
..00101011
+ 10010010
----------
..10111101
But there are all sorts of clever, nifty tricks to use simple addition to get the results of subtraction, multiplication, division, root extraction, and from there, any mathematical operation in the most advanced math textbook.
Then, beyond math tasks, digital computer CPUs can also manipulate big strings of 0's and 1's and interpret them as language text -- i.e., store and access and do all sort of tricks with Shakespeare's plays or "Histoire d'O" (1955 winner, Prix des Deux Magots).
Here is the Instruction Set of one of the earliest computer CPU chips, the Intel 8080. (The Z80 uses the same Instruction Set, it's just souped-up for faster speed.)
Here are two fairly simple, straightforward instructions. "Increment" just means to add one to whatever number resides in register C, and "decrement" subtracts one from the number in register C.
Machine Assembly
Language Language
Code Mnemonic Instruction
==========================================
OC INR C Increment register C
OD DCR C Decrement register C
OC and OD are the hexadecimal (base 16) notation of the instruction. It's a compressed notation for human convenience, but easily translated into binary, the only notation the CPU understands and can manipulate:
hex binary
=============
0C = 00001100
0D = 00001101
INR and DCR are Assembly Language mnemonics for each instruction. Assembly Language is one step friendlier for human programmers than Machine Language.
(In practice, it's really impossible for humans to work with or make sense of just 000101100100110011000101 ...)
My favorite instruction is
00 NOP No Operation
... an instruction that does absolutely nothing.
But it's an instruction, and when the CPU encounters it in a program, it must execute it, exactly as it must execute 0C or 0D.
But doing absolutely nothing takes time -- a very short but specific amount of time -- to execute. And sometimes a time delay is exactly what the programmer needs. So if at a particular point in a program, you want the computer to just sit there and twiddle its thumbs for 0.721 seconds, you might write something the CPU would execute as
DO THE NEXT INSTRUCTION 123 TIMES
NOP
I have suspicions that there are a few mistakes in this (filched) 8080 Instruction Set, but you'll get the idea. Just don't rely on it to program an automobile's engine, fuel or braking electronics, or to run the in-flight systems of an Airbus airliner, or an important system -- like Life Support -- on a rocket ship to Mars. Call Intel, get their documentation, use their authorized 8080 Instruction Set.
Here it is, here's everything the Intel 8080 Central Processing Unit chip knows how to do.
======================================
8080 Instruction Set
Add Instructions
80 ADD B Add register B
81 ADD C Add register C
82 ADD D Add register D
83 ADD E Add register E
84 ADD H Add register H
85 ADD L Add register L
86 ADD M Add memory
87 ADD A Add register A
88 ADC B Add register B with carry
89 ADC C Add register C with carry
8A ADC D Add register D with carry
8B ADC E Add register E with carry
8C ADC H Add register H with carry
8D ADC L Add register L with carry
8E ADC M Add memory with carry
8F ADC A Add register A with carry
C6 ADI Imm Add immediate
CE ACI Imm Add immediate with carry
19 DAD D Add register pair DE to HL
29 DAD H Add register pair HL to HL
39 DAD SP Add register SP to HL
09 DAD B Add register pair BC to HL
And Instructions
A0 ANA B And register B
A1 ANA C And register C
A2 ANA D And register D
A3 ANA E And register E
A4 ANA H And register H
A5 ANA L And register L
A6 ANA M And memory
A7 ANA A And register A
E6 ANI Imm And immediate
Call Instructions
C4 CNZ Addr Conditional Subroutine Call (Not Zero Flag)
CC CZ Addr Conditional Subroutine Call (Zero Flag)
CD CALL Addr Subroutine Call
D4 CNC Addr Conditional Subroutine Call (Not Carry Flag)
DC CC Addr Conditional Subroutine Call (Carry Flag)
E4 CPO Addr Conditional Subroutine Call (Parity Odd, Not Parity Flag)
EC CPE Addr Conditional Subroutine Call (Parity Even, Parity Flag)
F4 CP Addr Conditional Subroutine Call (Positive, Not Sign Flag)
FC CM Addr Conditional Subroutine Call (Minus, Sign Flag)
Compare Instructions
B8 CMP B Compare register B
B9 CMP C Compare register C
BA CMP D Compare register D
BB CMP E Compare register E
BC CMP H Compare register H
BD CMP L Compare register L
BE CMP M Compare memory
BF CMP A Compare register A
FE CPI Imm Compare immediate
Decrement Instructions
0B DCX B Decrement register pair BC to HL
0C INR B Increment register C
0D DCR B Decrement register C
13 INX D Increment register pair DE
14 INR D Increment register D
15 DCR D Decrement register D
1B DCX D Decrement register pair DE to HL
1C INR E Increment register E
1D DCR E Decrement register E
03 INX B Increment register pair BC
23 INX H Increment register pair HL
24 INR H Increment register H
25 DCR H Decrement register H
04 INR B Increment register B
2B DCX H Decrement register pair HL to HL
2C INR L Increment register L
2D DCR L Decrement register L
05 DCR B Decrement register B
33 INX SP Increment register SP
34 INR M Increment memory (HL)
35 DCR M Decrement memory (HL)
3B DCX SP Decrement register SP to HL
3C INR M Increment register A
3D DCR M Decrement register A
Exclusive Or Instructions
A8 XRA B Exclusive Or register B
A9 XRA C Exclusive Or register C
AA XRA D Exclusive Or register D
AB XRA E Exclusive Or register E
AC XRA H Exclusive Or register H
AD XRA L Exclusive Or register L
AE XRA M Exclusive Or memory
AF XRA A Exclusive Or register A
EE XRI Imm Exclusive Or immediate
Interrupt Instructions
F3 DI Disable Interrupt
FB EI Enable Interrupt
Jump Instructions
C2 JNZ Addr Conditional Jump (Not Zero Flag)
C3 JMP Addr Jump to Direct Address
CA JZ Addr Conditional Jump (Zero Flag)
D2 JNC Addr Conditional Jump (Not Carry Flag)
DA JC Addr Conditional Jump (Carry Flag)
E2 JPO Addr Conditional Jump (Parity Odd, Not Parity Flag)
E9 PCHL Jump Indirect HL
EA JPE Addr Conditional Jump (Parity Even, Parity Flag)
F2 JP Addr Conditional Jump (Positive, Not Sign Flag)
FA JM Addr Conditional Jump (Minus, Sign Flag)
Load Instructions
01 LXI B Load Immediate register pair BC
0A LDAX B
0E MVI B Move Immediate register C
11 LXI D Load Immediate register pair DE
16 MVI D Move Immediate register D
1A LDAX D
1E MVI E Move Immediate register E
21 LXI H Load Immediate register pair HL
26 MVI H Move Immediate register H
2A LHLD Addr
2E MVI L Move Immediate register L
31 LXI SP Load Immediate register SP
3A LDA Addr Load Direct
06 MVI B Move Immediate register B
3E MVI M Move Immediate register A
Move Instructions
F9 SPHL
Or Instructions
B0 ORA B Or register B
B1 ORA C Or register C
B2 ORA D Or register D
B3 ORA E Or register E
B4 ORA H Or register H
B5 ORA L Or register L
B6 ORA M Or memory
B7 ORA A Or register A
F6 ORI Imm Or immediate
Other Instructions
00 NOP No Operation
76 HLT Halt
D3 OUT Port Output from Port Direct
DB IN Port Input from Port Direct
E3 XTHL
EB XCHG
27 DAA Decimal Adjust
2F CMA Complement Accumulator
37 STC Set Carry Flag
3F CMC Complement Carry Flag
Reset Instructions
C7 RST 0 Reset 0
CF RST 4 Reset 4
D7 RST 1 Reset 1
DF RST 5 Reset 5
E7 RST 2 Reset 2
EF RST 6 Reset 6
F7 RST 3 Reset 3
FF RST 7 Reset 7
Return Instructions
C0 RNZ Addr Conditional Subroutine Return (Not Zero Flag)
C8 RZ Addr Conditional Subroutine Return (Zero Flag)
C9 RET Addr Subroutine Return
D0 RNC Addr Conditional Subroutine Return (Not Carry Flag)
D8 RC Addr Conditional Subroutine Return (Carry Flag)
E0 RPO Addr Conditional Subroutine Return (Parity Odd, Not Parity Flag)
E8 RPE Addr Conditional Subroutine Return (Parity Even, Parity Flag)
F0 RP Addr Conditional Subroutine Return (Positive, Not Sign Flag)
F8 RM Addr Conditional Subroutine Return (Minus, Sign Flag)
Rotate Instructions
0F RRC Rotate Right
17 RAL Rotate Left with Carry
1F RAR Rotate Right with Carry
07 RLC Rotate Left
Stack Instructions
C1 POP B Pop register pair BC
C5 PUSH B Push register pair BC
D1 POP D Pop register pair DE
D5 PUSH D Push register pair DE
E1 POP H Pop register pair HL
E5 PUSH H Push register pair HL
F1 POP SP Pop register pair PSW & A
F5 PUSH SP Push register pair PSW & A
Store Instructions
70 MOV M,B Store register B
71 MOV M,C Store register C
72 MOV M,D Store register D
73 MOV M,E Store register E
74 MOV M,H Store register H
75 MOV M,L Store register L
77 MOV M,A Store register A
12 STAX D
02 STAX B
22 SHLD Addr
36 MVI M Move Immediate memory (HL)
3A LDA Addr Load Direct
Store Instructions
70 MOV M,B Store register B
71 MOV M,C Store register C
72 MOV M,D Store register D
73 MOV M,E Store register E
74 MOV M,H Store register H
75 MOV M,L Store register L
77 MOV M,A Store register A
12 STAX D
02 STAX B
22 SHLD Addr
36 MVI M Move Immediate memory (HL)
3A LDA Addr Load Direct
Subtraction Instructions
90 SUB B Subtract register B
91 SUB C Subtract register C
92 SUB D Subtract register D
93 SUB E Subtract register E
94 SUB H Subtract register H
95 SUB L Subtract register L
96 SUB M Subtract memory
97 SUB A Subtract register A
98 SBB B Subtract register B with borrow
99 SBB C Subtract register C with borrow
9A SBB D Subtract register D with borrow
9B SBB E Subtract register E with borrow
9C SBB H Subtract register H with borrow
9D SBB L Subtract register L with borrow
9E SBB M Subtract memory with borrow
9F SBB A Subtract register A with borrow
D6 SUI Imm Subtract immediate
DE SBI Imm Subtract immediate with borrow
9 comments:
Now dig this: The 8080 was waaaaay before my time. It ran on 2 mHz and had a capacity of 6000 transistors. The latest Sandy Bridge models from intel run on ca. 2.5 GHz (but can apparently be overclocked up to 3,5) and host billions of transistors. Think of it this way: Take the population of Greater London (about 2 million) and multiply that around 200 times, all that on the size of a fingertip.
And here is the kicker: Moore’s Law, which states that the capacity of a chip doubles every 18months or so will soon come to its phsical limits. Experts still disupte when that will happen, either this decade or before 2030, the claims vary. Moore himself said it will be around 2017, other experts are more optimistic.
Then things will be verrry interesting. Might well be that nanaotechnology will be adapted, possibly fiberoptics, there is even talk of putting our knowledge of quantum mechanics to use. In any case this will be one of the most interesting transitions in scientific and engineering history !
What made my IMSAI primitive wasn't its 8080 chip. In 1977, the IMSAI used audio cassettes (or punched paper tape) as off-line digital storage. For a monitor, I had to modify a little black-and-white Hitachi TV set. Later I bought one of the first alphanumeric keyboards for input.
But for brainpower alone, my guess is my IMSAI and its 8080 was equivalent to all the digital computing power of all the combatants of World War II.
Ah, yes, reminds me of those happy days we had with the Commodore 64. The games were copied on audio tapes. I remember one time we wanted to play Olympic Games Los Angeles and we were all excited because this was new. And in color ! sometimes you were lucky and a game would run in about 5 minutes and not crash. We had to wait 20 minutes and the game crashed after 2 minutes. Now try to tell that to a kid with a more sophisticated game on his bloody cellphone !
I also have fond memories of the first Laptop i was able to use. It was a Compaq which looked very similar to an Osborne I. One heavy monochrome mother running on DOS with 7.5 " diskettes. i still remember being hunched over that keyboard looking into that tiny screen playing Sokoban. Happy, innocent days. Back then the idea of being on the brink to quantum computing was still SF. These days it is very likely I will see one of these machines in my lifetime.
Oh btw the Z1 from Konrad Zuse built in 1937 or so ran on 1 mHz. Einac also from around that time had a total weight of 27 tons.. And the first chess machine based on ideas of Samuel Babbage was built in the 1890s. Waaaay to go !
In 173 BC, I went to one of the first home/personal computer conventions ever, in New York City, and there was Adan Osborne, who wrote The Bible of home computing. I got his autograph! He died in 2003 ... here's his obit:
http://naturalscience.com/ns/news/news44.html
Now THAT is class, having Osborne's autograph ! There is a computer museum where I live and they got an Osborne 1. Must go there once on a rainy day.
There is also a business rule called Osborne's Law which states that you should never announce a newproduct in development while your previous model has just been shipped. It is named after Osborne who did just that and basically committed financial suicide by announcing the Osborne 2 just after the release of the Osborne 1. Poor bugger.
It was always pretty clear that Osborne had lots of amazing talents -- but being a smart businessman (like Bill G.) was not one of them.
I was just reading about my IMSAI, and its creator -- who had a big commercial success with his computers -- forced his entire work force to take EST -- Erhardt Seminar Training. At that time it was a hugely popular Self-Actualization cult.
The big cheese of the massive energy fraud company Enron pushed all his top executives into getting Lasik surgery for their eyes -- oh, please don't ask me why. Some of these business geniuses are loooooooooooooony.
Oh yeah, like this horrible Napoleon Hill stuff. Bleh !
You want to have a look at the future ? Since Moore's Law must come to its physical limitations one day, quantum computing might be the answer:http://www.engadget.com/2011/03/25/researchers-show-off-scalable-architecture-for-quantum-computing/
Chances are good that you and I will see this happen. And before someone asks about Artificial Intelligence, forget that. Too complex for various reasons, including hardware. We are not even close, not even with quantum technology. But I digress.
AI is gonna make its advances not smoothly, not universally ... but one achievement at a time. Like chess, which once seemed the pinnacle of human intelligence. Now a digital box can knock the shit out of a human world chess champion (and the box doesn't even know it's playing chess).
One indication of the progress of AI is the growing number of Life-And-Death functions we are increasingly willing to entrust entirely to software. I'm thinking specifically of aviation and medicine.
Question: Don't these conclusions come from Game Theory ?
At present and to my knowledge science is not even sure how to define the term consciousness and neurology has a hard time actually showing where a thought originates within the brain, wether it is a single event or a swarm. That knowledge will be vital in developing AI.
At present that chess box, Asimo and that thingy what was on Jeopardy are only toys, let us see what the future holds
I doubt that I will see AI in my lifetime, but it will be most interesting to follow these graduating steps indeed. I just read an interesting book by Michio Kaku which covers many of these subjects. More info as I read on.
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