Category: Fans of IBM z

These are easy to pick up – handy, too, if you want to write 64-bit addressing programs. If you are changing addressing modes from 31 to 64, say, you have some 31-bit addresses that need to be expanded to 64-bit. Well, these are the instructions you need. Read about them here and here.

This week I am in lovely Vilnius with my son before starting a week of assembler training. I’ll post some pictures below. The castle is in Trakai, a short drive outside the city. The bust is of Frank Zappa, Rock on Vilnius!

On a different note, Amit Sharma was kind enough to interview me for his wonderful Tech Sharmit podcast.You can listen to the interview here. You can catch Amit on YouTube here. Thanks again, Amit!

There is still time to register for the free virtual conference. Starts soon. Read about it here: https://ibmzday.bemyapp.com

Multiply Single (MS) provides another way to multiply binary integers using a single register. Read about it here.

The LAA (Load and Add) instruction packs two operations into one instruction. While you might not want to use it as a single instruction, it seems well- designed for looping, so withhold your initial judgment. There is an added benefit to learning this one – there are lots of other “LOAD AND …” instructions. Learn this one and you will know others by association. Here is the writeup.

Go large, go Grande. There’s no end to the ways to load a register. Do you remember what type of instruction this is? Is is indexed? How about the displacement size? Review and remember here. Have a great weekend!

(In case the first link was bad, I’m sending it again.)
This is that instruction from the wrong side of the street—the one that’s a little mysterious and edgy. Dare you use it? Of course you will. Here it is, pal. Just don’t tell anyone: Load Byte High.

We continue to investigate various load operations that are available (of which there are many). Load Byte (LB) is easy one to pick up if you haven’t used it in the past. Here is the write up.

[IBM Z Day: Special Edition, on April 8th. Free training. Earn badges. Register Now – ibm.biz/ibmzday2025-se

I was a bit trigger-happy and hit publish accidentally. Here is what I wanted to send you:

We are loaded with Load instructions on IBM machines. Load and Test Grande Register is a useful instruction to keep at your fingertips. Read about it here.