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64-bit binary operations z/OS MVS Programming: Extended Addressability Guide SA23-1394-00 |
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64-bit binary operations perform arithmetic and logical operations
on 64-bit binary values. 64-bit AMODE allows access to storage operands
that reside anywhere in the 16-exabyte address space. In support
of both, z/Architecture® extends
the GPRs to 64 bits. There is a single set of 16 64-bit GPRs, and
the bits in each are numbered from 0 to 63.
All S/390® instructions
are carried forward into z/Architecture and
continue to operate using the low-order half of the z/Architecture 64-bit
GPRs. That is, an S/390 instruction
that operates on bit positions 0 through 31 of a 32-bit GPR in S/390 operates instead on bit
positions 32 through 63 of a 64-bit GPR in z/Architecture. You can think of the S/390 32-bit GPRs as being imbedded
in the new 64-bit GPRs.
Throughout the discussion of GPRs, bits 0 through 31 of the 64-bit
GPR are called the high-order half, and bits
32 through 63 are called the low-order half.
The purpose of this section is to help you use the 64-bit GPR and the 64-bit instructions as you want to save registers, perform arithmetic operations, access data. It is not a tutorial about how to use the new instruction set. Principles of Operation is the definitive reference book for these instructions. This section, however, describes some concepts that provide the foundation you need. After you understand these, you can go to Principles of Operation and read the introduction to z/Architecture that appears in the first chapter and then refer to the specific instructions you need to write your program. |
Copyright IBM Corporation 1990, 2014
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