Re: A contest...with a prize!
I, too, had one of those 'euphoric' experiences when I read your response!
It was a bright, yet dull sensation that started in the palm of my hand and
proceeded down through..... No, wait, that was when I was healed with my
hand touching a television screen,
Anyway. I have never experienced that environment, but I feel a sort-of
kinship. Although I did not touch my first computer until 1982. IBM Series I.
As long as I am waxing philosophical, this is a great chance for all of the
younger programmers to acknowledge the wealth of experience they have
available to them on this list. As a beginner, I would have relished the
chance to read some of these discussions on logic, design, etc. I think
that is why many of you are so patient and level headed with your responses
to the 'simple' or 'intro' questions.
Let's NOT separate the lists.......
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Well Irv beleive it or not I recognised those HEX bytes at first glance. I
spent so many hours in 1978 programming a CDP1802 machine on a Hexadecimal
keypad and only
LED for display (not even and hex display just binary code)
00 38 SKP ; skip next byte
01 00 ; data byte
02 F8 01 LDI 01 ; load immediate register D with 01
04 A1 PLO R1 ; put register D in low byte of R1
05 E1 SEX 1 ; set register X with 1
06 64 OUT4 ; out to device 4 M(R(X)) -> BUS
07 21 DEC R1 ; decrement R1
08 F0 LDX ; load register D via register X
09 A2 PLO R2 ; put register D in low byte of register 2
0A 6C INP4 ; input from device 4 (data send to D and M(R(X))
0B FA 0F ANI 0F ; AND immediate D with 0F
0D FB 0F XRI 0F ; XOR immediate D with 0F
0F C6 LSNZ ; long skip (skip 2 bytes) if D not 0
10 7B SEQ ; set Q output line. (this is a single bit output on
CDP1802)
11 38 NBR ; skip next byte
12 7A REQ ; reset Q line
13 F0 LDX ; load register D via register X
14 FA 0F ANI 0F ; AND immediate D with 0F
16 FD 09 SDI 09 ; substract D immediate i.e D-09
18 3B 23 BNF 23 ; short branch to 23 if DF = 0
1A F0 LDX ; load register D via register X
1B FA F0 ANI F0 ; AND immediate D with F0
1D FD 90 SDI 90 ; substract D immediate i.e. D-90
1F 3B 23 BNF 23 ; short branch to 23 if DF = 0
21 30 27 BR 27 ; short branch to 27
23 82 GLO R2 ; get low byte of register 2 in D
24 51 STR R1 ; store D in memory via register 1
25 64 OUT4 ; output M(R(X)) to device 4
26 21 DEC R1 ; decrement R1
27 3F 06 BN4 ; short branch to 06 if EF4 = 0 (EF4 is an input line of
CDP1802)
29 7B SETQ ; set Q line
2A F8 90 LDI 90 ; load D immmediate with 90
2C B3 PHI R3 ; put D in hi byte of register 3
2D 23 DEC R3 ; decrement register 3
2E 93 GHI R3 ; get hi byte of R3 in D
2F 3A 2D BNZ ; short branch to 2D if D not 0
31 F0 LDX ; load D with containt of memory pointed by X i.e. D =
(R(X))
32 FA 0F ANI 0F ; AND immediate D with 0F
34 3A 3A BNZ 3A ; short branch to 3A if D not 0
36 F8 06 LDI 06 ; load D with 06
38 F5 SD ; subtract D from memory i.e. M(R(X)) - D -> D, DF
39 51 STR R1 ; store D in memory via register 1 D->M(R(N))
3A F8 01 LDI 01 ; load D with 01
3C F5 SD ; M(R(X)) - D -> D, DF
3D 51 STR R1 ; D -> M(R(N))
3E 64 OUT4 ; output to device 4 via R(X) i.e. M(R(X) -> BUS
3F 21 DEC R1 ; decrement register 1
40 3A 2A BNZ 2A ; branch to 2A if D not 0
42 7A REQ ; reset line Q
43 82 GLO R2 ; low byte of R2 in D i.e. R2.0 -> D
44 51 STR R1 ; D -> M(R(1))
45 30 06 BR 06 ; branch to 06
(code deassembled by hand)
This is code for RCA CDP1802 microprocessor. The computer was probably a
COSMAC ELF
Popularized by "Popular electronics" in 1977 (or 1978).
I don't understand yet what is does. (what device was connected to output
4, line Q
and input line EF4 ? )
On my machine there was a LED on the Q line so codes 7B and 7A was flashing
de LED.
I connected a speaker on that line too and produce sound effects with it.
I even code a program to play tunes.
Regards,
Jacques Deschenes
Baie-Comeau, Quebec
Canada
desja at globetrotter.qc.ca
<*************** END OF ORIGINAL MESSAGE ************>
Joe Phillips, Assistant Director
Information Technology Services
Texas Wesleyan University 817-531-4284
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