Learn IBM Assemb;y Lsnhushr
When I was a kid, the Coasters had a big hit with Searchin’. If you are searchin’ for a particular character in a string, you can use TRT or try an easier route – use SRST (Search String). SRST avoids having to build a TRT table. And if you aren’t searchin’, take a break and listen to a classic. You can read about SRST here.
These “Greek” instructions use three registers, so learning to ADD (Greek) should be easy. You can find a link to the AGRK instruction here.
All articles are on the main site, but here is a link to the latest one.
Multiply Greek! At least that’s how I remember it. Greek is a good mnemonic for MGRK. Use this instruction to multiply grande registers. This instruction has a simple setup, so it’s easy to use. Find it here.
For small, binary integer multiplications, you can use MH or MHI. With MHI, the second operand is stored as an immediate constant inside the instruction. The condition code isn’t set, so you have to be careful not to overflow the limits of the computation. Still, it’s a handy instruction. See some examples, and learn the details here.
I write mysteries when I’m not working with assembler or playing with my dog, Rocco. I recently did an an interview with author Marcia James about my novels, the second of which contains a dog as an important part of the story. You can read about it on her site here. Order a novel (On Amazon) as a way to support the site!
Just a few more multiplication instructions, and we will move forward in the alphabet from “M”. MHY is a companion instruction to MFY. These two instructions share the same instruction format: RXY-a. Remember that “Y”-type instructions can reach farther from the base address, both forward and backward. You can find a writeup here.
I’m working on writing an article about each multiply instruction on the machine. Today’s instruction, Multiply Grande Halfword (MGH), provides an easy way to multiply a halfword value times a Grande Register value. It only takes a few minutes to review it here.
I’m still working my way alphabetically (ususally) through the instruction set, picking instructions you should learn. We are in the M’s and there’s a plethora of multiply instructions we can review. I’m also selecting instructions I haven’t already covered. Today’s instruction is Multiply Single Register (MSR), which provides an easy way to multiply two single-precision register values without much setup. The result should be single-precision if you want to use this instruction. Read about MSG here.