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

Default is: ARCH(8)

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 option.
Use the ARCH level that matches the lowest machine architecture where your application runs.

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

8

Produces code that uses instructions available on the 2097-xxx (IBM® System z10® EC) and 2098-xxx (IBM System z10 BC) models in z/Architecture® mode.

Specifically, these ARCH(8) machines and their follow-ons add instructions supported by the general instruction extensions facility.

9

Produces code that uses instructions available on 2817-xxx (IBM zEnterprise® 196) and 2818-xxx (IBM zEnterprise 114) models in z/Architecture mode.

Specifically, these ARCH(9) machines and their follow-ons add instructions supported by the following facilities:

• High-word facility
• Interlocked access facility
• Load/store-on-condition facility
• Distinct-operands facility
• Population-count facility

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 8561-xxx (IBM z15) 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

Note:
A higher ARCH level includes the facilities of the lower ARCH level.
For example, ARCH(13)includes all the facilities of the lower ARCH levels.

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