Reverse engineering ARM1

[Phynaz]

Very interesting read. With the simulator you can see the actual bits flow through the chip.

http://www.righto.com/2015/12/reverse-engineering-arm1-ancestor-of.html

 

[William Gaatjes]

Interesting read indeed. Thank you.

Links from the same site but also fun :

http://spectrum.ieee.org/semiconductors/processors/25-microchips-that-shook-the-world

http://www.pcworld.com/article/171171/influential_processors.html#slide10

 

[Schmide]

I had to disable that graphic to read the article lol

 

[Nothingness]

Another interesting read: http://daveshacks.blogspot.co.uk/2015/12/inside-alu-of-armv1-first-arm.html

 

[William Gaatjes]

I find that barrel shifter amazing. The ARM core can shift a value in a register in the same as it does the ALU operation. shift and rotating together with an ALU operation without needing extra clock cycles, if i remember correctly.

 

[Exophase]

Something I found interesting and surprising was that ARM1 uses a ripple-carry adder in its ALU instead of a more efficient carry-lookahead scheme. This was probably a major limiter in the clock speed. It looks like this was changed for ARM2.