Bentium Pro ALU: Overview, Registers, Adder, Logic, Shift/Rotate and Schematics
My Bentium Pro computer is a Ben Eater inspired machine which uses many of the same ideas and many identical or very similar circuits. My intention with these blog posts was to write about the things I have added or done differently and leave the same/similar stuff for people to copy from Ben. I also …. Read More
The Bentium Pro Flags Register
After giving you a general tour of the ALU of the Bentium Pro and the carry select circuitry I want to move onto describing the flags register and how the flags are evaluated. As a reminder, the Bentium Pro has four flags: Carry. This can contain the carry/borrow from the adder and also the bit …. Read More
Adding ADC, SBC, INC & DEC Operations To Ben Eater’s ALU
The ALU on Ben Eater’s original Bentium 8-bit computer has two operations: add (ADD) and subtract (SUB). This gives his design the ability to add and subtract 8-bit numbers. But if you want to add or subtract larger numbers then you need more than 8 bits. You could do this by expanding to a 16-bit …. Read More
My Breadboard ALU With Twenty Operations
Last year I built Ben Eater’s 8-bit breadboard computer, which taught me a lot about how processors work. But with only 16 bytes of memory it’s not really usable for any kind of real world tasks. As soon as I’d finished it I knew I wanted to make some upgrades. And when I looked at …. Read More