1. xerox 560 computer system - The UK Mirror Service

• Extensive instruction set that includes:• Byte, halfword, word, and doubleword operations.• Use of all memory-referencing instructions forregister-to-register operations, with or withoutindirect addressing and postindexing, and withinnormal instruction format.• Multiple register operations.• Fixed-point integer arithmetic operations in halfword,word, and doubleword modes.• Immediate operand instructions.• Floating-point hardware operations in short andlong formats with significance, zero, and normalizationcontrol and checking, all under full programcontrol.• Full complement of logical operations (AND, OR,exclusive OR).• Comparison operations, including compare betweenlimits (with I imits in memory or in registers).• Call instructions that permit up to 64 dynamicallyvariable, user-defined instructions, and allow aprogram access to operating system functions withoutoperating system intervention.• Decimal hardware operations, including arithmetic,edit, and pack/unpack.• Byte-string instructions.• Push-down stack operations (hardware implemented)of single or multiple words, with automaticI imit checking, for dynamic space allocation,subroutine communication, and recursiveroutine capabi lity.• Automatic conversion operations, including binary/BCD and any other weighted-number systems.• Analyze instruction that facilitates effectiveaddress computation.• Interpret instruction that increases speed of interpretiveprograms.• Shift operations (left and right) of word or doubleword,including logical, circular, arithmetic,searching shift, and floating-point modes.• Built-in reliability and maintainability features thatinclude:• Extensive error logging. When a fault is detected,system status and fault information are availablefor program retrieval and logging for subsequentanalysis.• Full parity checking on all data and addressescommunicated in either direction on buses betweenmemory units and processors, providing fault detectionand location capability to permit theoperating system or diagnostic program to quicklydetermine a faulty unit.• Address stop feature that permits operator or maintenancepersonnel to:Stop on any instruction address.Stop on any memory reference address.Stop when any word in a selected page ofmemory is referenced.• Traps that provide for detection of a variety offault conditions, designed to enable a high degreeof system recoverab iii ty .• Partitioning features that enable system reconfigurationvia a centralized Configuration ControlPanel. Units may be partitioned from the systemby selectively disabling them from buses (assumingother system facilities can handle the additionalload). Thus, faulty units, processors, devices, oran alternate system can be isolated from the operationalsystem to enable diagnosis or repair whi Iethe primary system continues operation.• Independently operating I/O system with the followingfeatures:• Direct input/output (READ DIRECT, WRITE DIRECTinstructions) for transfer of 32-bit words betweenthe specified general register and an external device;a 16-bit address is transferred for selectionand control purposes; and each transfer is underdirect program control.• Up to five independent I/O processor clusters (restrictedonly by the maximum number of 6 ports).• Multiplexor I/O processors (MIOPs) (up to 3 perI/O cluster), each providing for simultaneous operationof up to 16 devices per processor.• Data chaining for gather-read and scatter-writeoperati ons.• Command chaining for multiple record operations.• Write lock protect feature within memory unitfor positive protection from all processors storinginto memory.• Comprehensive modular software that is program compatiblewith Sigma 5-9 computers:•Expands in capabi I i ty and speed as system grows.•Operating system: Control Program-Five (CP-V).2 General Characteristics