1. xerox 560 computer system - The UK Mirror Service

(P-Mode)GSPECIAL INSTRUCTION SINGLE STEPThis command permits the contents of register Q5 to be interpretedas the current instruction, and execution by theBP proceeds as described for the INSTRUCTION SINGLESTEP command. The program counter is incremented by + l.This command thus allows any single instruction (containedin register Q5) to be executed in lieu of the instructionpointed to by the program counter without otherwise disturbingconditions within the system. The resultant displayshows the next instruction to be executed.Condition codes resulting from the instruction executionare displayed as the second hexadecimal digit of the addressfield.Input Display Name of CommandZC MM2 (MM2) SET/CLEAR CLUSTERDISPLAY MODEZC MM3 (MM3) SET/CLEAR P-MODE REPEATMODEZc MM4ttZc MM5tt(MM echo SUPER RESETinterrupted)(MM5)SET MICRO-DIAGNOSTICLOOP MODEZcMMlt (MM6) INITIATE ELEMENT MICRO-DIAGNOSTIC(P-Mode)XEXIT P-MODEZcMMlt (MM7) SET LOW CLOCK MARGINSZc MM8tt (MM8) SET HIGH CLOCK MARGINSThe EXIT P-MODE command terminates the P-Mode withinthe ECS. The BP resumes execution of instructions. Ifno SYSTEM RUN or LOAD NORMAL commands were in effectbefore entering the P-Mode, the system remains in theIDLE state.Zc MM9 tt (MM9) SET MEMORY INTERLEAVEOVERRIDEZcMMAtt (MM echo SET DISPLAY INHIBIT MODEinterrupted)ZCCLKtt (CLK) SET SINGLE CLOCK MODEIspace' t Ispace l SINGLE-CLOCK STEPMAINTENANCE CONTROL COMMANDSMaintenance control commands faci I itate isolation andanalysis of system hardware malfunctions. The 'c~mmandsare accepted only if the SCC FUNCTIONS switch is in theENABLE position. In addition, most critical maintenancecontrols can be activated only if the MAINT MODE switchon the SCP is in the ON position.The primary features of the maintenance control commandsare the provision of system clock control and single clockstatus displays. SturU5 is obtuined ffOffl feud-only regi:5tellilocated in central system elements. These Single Clock StatusRegisters (SCSR) monitor the state of internal hardwaresignals. Each SCSR display is printed on the next line ofSCC printout in the format II CE:DDDDDDDD CC". The II CEilfield contains two hexadecimal digits that represent a clusterand an element address, respectively. The 8-digit D fielddisplays the contents of the register, and the 2-digit II CC"field is a modulo 256 clock step counter. This informationis valid only when the system clock is stopped.The following maintenance control commands are includedas standard features of this computer system:ZCCNNt (CNN) MUL TIPLE-CLOCK STEPZC KIL (KIL) CLEAR SINGLE CLOCKMODEZc E ## (EN#) SELECT/DISPLAY SINGLECLOCK STATUS REGISTERZC T (T) SET/CLEAR TRANSPARENTTEXT MODEZC LDS#### (LDS@###N) LOAD SPECIALZC LDT (LDT) MEMORY SETSET SINGLE CLOCK MODEThis command sets the computer system to the II Single ClockMode" by simultaneously stopping all central system clocks,except those required by the External Control Subsystemand the I/O system. When the system is in the SingleClock Mode all control commands may be entered and executed.Operations performed in the Single Clock Modemay differ from those performed when the clock is runningInputZCIvW\ODisplay(MMO)Name of CommandCLEAR MM FEATUREStAil clock controls are inhibited unless the MAINT MODEswitch is in the ON position.ZcMM1t(MM1)SET/CLEAR REPEAT CLOCK­ING MODEttThese commands are accepted only if the system is in theMAINT MODE.158 Control Commands