ARCH

The ARCH option specifies the machine architecture for which the executable program instructions are to be generated.

ARCH option syntax

Default is: ARCH(10)

Abbreviations are: None

If you specify a higher ARCH level, the compiler generates code that uses newer and faster instructions. Your application might abend if it runs on a processor with an architecture level lower than what you specified with the ARCH option. Use the ARCH level that matches the lowest machine architecture where your application runs. It is recommended that you set the ARCH level in your installation defaults (IGYCDOPT), rather than setting it in build tools, JCL, or CBL/PROCESS.

Current supported architecture levels and groups of models are as follows:

10

Produces code that uses instructions available on the 2827-xxx (IBM® zEnterprise® EC12) and 2828-xxx (IBM zEnterprise BC12) models in z/Architecture® mode.

Specifically, these ARCH(10) machines and their follow-ons add instructions supported by the following facilities:

Execution-hint facility
Load-and-trap facility
Miscellaneous-instructions-extension facility
Transactional-execution facility
Enhanced decimal floating point facility that enables more efficient conversions between zoned decimal data items and decimal floating point data items. Instead of converting zoned decimal data items to packed decimal data items to perform arithmetic when conditions permit it and the optimization level is greater than 0, the compiler converts zoned decimal data items directly to decimal floating point data items, and then back again to zoned decimal data items after the computations are complete.

11

Produces code that uses instructions available on 2964-xxx (IBM z13®) and 2965-xxx (IBM z13s®) models in z/Architecture mode.

Specifically, these ARCH(11) machines and their follow-ons add instructions with support of the following facilities:

Enhanced decimal floating point facility that enables more efficient conversions between packed-decimal data items and decimal floating point intermediate result data items when the surrounding conditions are optimal and the optimization level is greater than 0.
Exploitation of the vector extension facility (SIMD) instructions for some INSPECT REPLACING and INSPECT TALLYING statements.
To use the vector extension facility (SIMD) instructions, the code must be executed on a machine running on z/OS® V2.2, or z/OS V2.1 with the PTFs for APARs OA43803 and PI12412 installed.

12

Produces code that uses instructions available on 3906-xxx (IBM z14) and 3907-xxx (IBM z14 ZR1) models in z/Architecture mode.

Specifically, these ARCH(12) machines and their follow-ons add instructions that support the vector packed-decimal facility, which accelerates packed and zoned decimal computation by storing intermediate results in vector registers instead of in memory.

13

Produces code that uses instructions available on the 8561-xxx (IBM z15) and 8562-xxx (IBM z15 T02) models in z/Architecture mode.

Specifically, these ARCH(13) machines and their follow-ons add instructions supported by the following facilities:

Vector packed-decimal enhancement facility
Vector-enhancements facility 2
Miscellaneous instruction-extensions-facility 3
Aligned vector load/store hints

14

Produces code that uses instructions available on the 3931-xxxx (IBM z16) model in IBM z/Architecture mode.

Specifically, this ARCH(14) machine and its follow-ons add instructions supported by the new Vector Packed Decimal Enhancement Facility 2. This new facility adds performance improvements for COBOL programs that contain one or more of the following types of statements:

Exponentiation operations on packed or zoned decimal data items where the exponent is declared with one or more fractional digits
Arithmetic statements involving mixed decimal and floating-point data items
Statements using numeric-edited data items

Note: A higher ARCH level includes the facilities of the lower ARCH levels. For example, ARCH(14) includes all the facilities of the lower ARCH levels.

For more information about these facilities, see z/Architecture Principles of Operation.

Related references
TUNE