Tag: assembler

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

Here is a video discussion of the eleven load operations that were given a visual depiction last week. If you are not familiar with all of these loads, the video can help you quickly master these and give you a way to remember them easily.

Here is a video I made about the importance of “green cards”. Like all advice, it’s worth about what you pay for it 🙂 If you are new to assembler, you might learn something interesting.

This week, instead of an article about one instruction, I give you a visual depiction of the eleven load operations for an IBM z16. There are no words, so it’s something like a puzzle. You have to parse the diagrams to glean the information. Much is left out of course. No talk of addressing techniques, just the results of executing each instruction is depicted. But you may learn a new instruction or reinforce what you already know. Enjoy—it helped me. View the diagrams here. Let me know if you would like a video about this.

Thanks so much, IBM! I am delighted.

I’ve updated the article about LAY to include how to decrement a register with LAY. If you haven’t seen this before, it’s worth a look. Read about LAY here.

One thing that’s great about learning IBM assembler is that if you master one instruction, you often learn a handful of others by association. That’s the case with AGSI – Add Grande Storage Immediate, which is related to ASI. The G in AGSI suggests a register might be involved, but don’t be fooled. Both operands are in storage. The first operand is eight bytes – the size of a grande register,the second operand is a single immediate constant that occupies the second byte of the instruction. Get the details here. Watch the instruction in action with Visiblez here.