# z/Reference

> Technical reference for IBM's z/Architecture, covering instructions, assembler, and interrupts. (iPhone/iPad app by Genie Software LLC.)

- Source: https://appshunter.io/ios/app/zreference/id731406630 (this page in markdown: same URL + `.md`)
- Developer: [Genie Software LLC](https://appshunter.io/developer/731406633)
- Category: Reference
- Price: Free
- Rating: 4.00/5 from 1 App Store ratings · 1 written reviews indexed
- Age rating: 4+
- Requires: iOS 15.0 · 13 MB
- Languages: English
- Released: 2013-10-30
- Data updated: 2026-06-10
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/zreference/id731406630/reviews.md

## What is z/Reference?

z/Reference is a technical reference app for IBM’s® z/Architecture®.  This app provides quick access to information found in IBM’s z/Architecture Reference Summary.  

Features:

Instructions:
   - Lists 983 instructions sorted by name, mnemonic and opcode
   - Search on instruction name, mnemonic and opcode
   - Groups the instructions by type (general, control, decimal, floating point, etc.)

Instruction Condition Codes:
   - Lists the instruction condition codes by instruction type (e.g. General, Decimal, etc.) 
  
Assembler:
   - Lists the assembler instructions by type (e.g. USING, DROP, etc.)
   - Lists the assembler system variables (e.g. &SYSDATC, &SYSDATE, etc.)
   - Lists the assembler options (e.g. ADATA, ALIGN, etc.)

Interrupts:
   - Lists the interrupt types/categories (e.g. external, I/O,  program, etc.)
   - Lists the external interrupt types (e.g. x‘1004’, x‘1005’, etc.)
   - Lists the program interrupt types (e.g. 0C1, 0C4, etc.)

PSW:
   - Formats both the z/Architecture PSW and ESA/390 PSW

CNOP:
   -Lists the various CNOP alignments

Printer:
   - Lists the ANSI and machine printer control characters

Powers of 2 and 16:
   - Lists the powers of 2 and 16


IBM and z/Architecture are registered trademarks of International Business Machines Corporation.

## Key features

- 983 instructions sorted by name, mnemonic, and opcode
- Instruction condition codes by type
- Assembler instructions, system variables, and options
- Interrupt types and categories
- z/Architecture and ESA/390 PSW formatting
- Printer control characters

## Recent user reviews (1 of 1)

All indexed reviews: https://appshunter.io/ios/app/zreference/id731406630/reviews.md

### 4/5 — More instruction information please

*2018-07-14, version 2.0*

Would be way more useful if you guys could provide expanded information on instructions etc...similar to the information in the “z/Architecture IBM Principles of Operation” also a search function to would be great. As it is now it’s more useful to download the POPS manual PDF document and use that. I know the market for this type of app is small so development costs vs return is a factor...but would love to see more if possible. I will still use it, so thanks for what you have...it’s good to see anything in the “z World”...so gave it 4 stars anyway 😊 P.S. - Same for the JCL app.

## Frequently asked questions about z/Reference

### What is z/Reference?

z/Reference is a technical reference application designed for IBM's z/Architecture. It offers quick access to detailed information on instructions, assembler elements, interrupts, and more, mirroring content from the z/Architecture Reference Summary.

### What kind of instructions does z/Reference list?

z/Reference lists 983 instructions, categorized by type such as general, control, decimal, and floating point. You can search these instructions by name, mnemonic, or opcode.

### Does z/Reference cover assembler details?

Yes, z/Reference includes lists of assembler instructions by type (e.g., USING, DROP), assembler system variables (e.g., &SYSDATC), and assembler options (e.g., ADATA, ALIGN).

### What information is available on interrupts?

The app provides lists of interrupt types and categories, including external, I/O, and program interrupts. It also details specific external interrupt types and program interrupt codes.

### What devices is z/Reference available on?

z/Reference is available on iPhone, iPad, and iPod devices, indicated by its support for these platforms.

### How often is z/Reference updated?

The latest version of z/Reference is 2.2.0, which was last updated on April 1, 2022. This indicates a relatively infrequent update cycle.

### What is the age rating for z/Reference?

z/Reference has an age rating of 4+, making it suitable for a wide range of users.

### Does z/Reference contain advertisements?

The provided data does not indicate the presence of advertisements. The app is listed as free and does not mention in-app purchases, suggesting a clean user experience.

## Version history (last 1 release)

### 2.2.0 — 2022-04-01

Updates for iOS 15
Minor changes to "Instruction Search"

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-10.*