The Punctilious Programmer IBM Mainframe Assembler Two’s Complement for Programmers

Two’s Complement for Programmers

Are you new to two’s complement data? Need to brush up your skills? I’ve posted a new article on the website that might help – Two’s Complement for Programmers. It’s not heavy on mathematics, but long on the basic skills you need as an assembler programmer.

It will become an appendix in my new book The Big Blue Assembler Book. I decided to change the title when the book grew longer – +300 pages. Then I realized that “Big Blue” is a nickname for IBM and the title was fixed!

I’ll be building a few more programming exercises and an index (any suggestions?). Then I’ll read the whole thing again looking for errors before publishing it on Amazon.

6 thoughts on “Two’s Complement for Programmers”

  1. Something I’ve had trouble with for years is understanding how Load Complement (LCR) differs from Load Negative (LNR). From a naive perspective, they seem very similar, perhaps even identical. But they’re clearly not, though I’d be hard pressed to explain exactly why! I’d love to see a clear explanation of the difference, with some kind of easy reference (analogy?) to help distinguish them in the future, so I don’t have to go back and study LCR every time I come across it or am tempted to use it.
    And does “XR 0,0” the same thing as “LCR 0,0”? Hmmm…

      1. Bravo Mr. Woolbright!
        An excellent, precise answer, the very next day even!
        You are the BEST!

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