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HP Forum Archive 21

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OT: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35
Message #1 Posted by Egan Ford on 30 Aug 2013, 2:06 p.m.

http://files.righto.com/calculator/sinclair_scientific_simulator.html

      
Re: OT: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35
Message #2 Posted by Steve Simpkin on 30 Aug 2013, 2:27 p.m.,
in response to message #1 by Egan Ford

Amazing, fascinating, unbelievable and disturbing all in one product!

            
Re: OT: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35
Message #3 Posted by Matt Agajanian on 30 Aug 2013, 3:27 p.m.,
in response to message #2 by Steve Simpkin

I'll second that vote! Although, I must say the math genius who devised his even more inventive algorithms is certainly a very amazing mathenatician!

            
Re: OT: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35
Message #4 Posted by Steve Simpkin on 30 Aug 2013, 5:52 p.m.,
in response to message #2 by Steve Simpkin

I vividly remember really wanting a Sinclair LED Black Watch when it first appeared around 1975. Given its high failure rate, I guess it is good I didn't get one. I did buy and build a Sinclair Wrist Calculator kit around 1977. It was hard to build but it did work, even if it had mechanical problems.
http://www.vintagecalculators.com/html/wrist_calculator.html
I also remember being intrigued (because of its low cost) by the Sinclair ZX80 computer when it came out but I already had a much more capable Ohio Scientific C1P by then. Memories....

      
Re: OT: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35
Message #5 Posted by Thomas Klemm on 30 Aug 2013, 5:39 p.m.,
in response to message #1 by Egan Ford

I was hoping this would happen.
For those interested here's the Operating Instructions from Katie's manual collection for pre-LCD electronic calculators.
That's where you can also find the Assembly Instructions.

Kind regards
Thomas

PS: I like Milo.

            
Re: OT: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35
Message #6 Posted by Katie Wasserman on 31 Aug 2013, 12:06 a.m.,
in response to message #5 by Thomas Klemm

If Milo was still around I'm sure he'd say something like, "Woof!" (which roughly translates into I like you too).

      
Re: OT: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35
Message #7 Posted by Thomas Klemm on 2 Sept 2013, 10:54 p.m.,
in response to message #1 by Egan Ford

Inspired by the Sinclair Scientific I came up with this program for the WP-34s to calculate the logarithm: 

LBL'LOG'
0
x<> Y
LBL 00
ENTER
SDR 002
-
INC Y
x>1?
GTO 00
DEC X
SDL 002
+
RCL/ 00
RTN
You have to initialize the register 00: 
1
STO 00
XEQ'LOG'
STO 00
Afterwards you can use it: 
SCI 4
5
XEQ'LOG'

6.9897 -1
I'm amazed by the accuracy of the results.

Cheers
Thomas

Edited: 2 Sept 2013, 11:21 p.m.

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