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IBM System/7 Functional Characteristics - All about the IBM 1130 ...

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111 111111111■11111.!The <strong>System</strong>/7 processor fetches and executes instructions in order to perform operationson data (such as testing, arithmetic, movement, and logical decision operations). Instructionsused by <strong>the</strong> processor are represented in a storage word by fixed patterns of bits, eachpattern indicating a specific operation to be performed by <strong>the</strong> processor in a certainpredetermined manner.INSTRUCTION CLASSESFor purposes of discussion and clarification, <strong>the</strong> instruction set is divided into classeswhich describe, in general, <strong>the</strong> type of data operation that is performed.Mnemonic symbols are used to abbreviate <strong>the</strong> instruction names when programming inAssembler language. Use of <strong>the</strong> leading P in <strong>the</strong> instruction mnemonics is required in all<strong>System</strong>/7 programs to be assembled on an <strong>1130</strong> or 1800 system, or using <strong>the</strong> <strong>System</strong>/7Stand-Alone assembler. The P or an X is always required in <strong>the</strong> Execute I/O instruction(PIO or XIO). The P is optional (except for PIO) when assembling on a <strong>System</strong>/360,<strong>System</strong>/370, or <strong>the</strong> <strong>System</strong>/7 Macro Assembler. The <strong>System</strong>/7 instructions, along with<strong>the</strong>ir mnemonics, operation codes, and execution times, are shown in Figure 4-1.4-2 GA34-0003

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