         BOUND     1F              FILE BOUND FOR RMS.MBOX      E2BIP35 0482.000
IPU.ICB  EQU       $         CPU ISSUED 'SIPU' INSTRUCTION              0483.000
IPU.OLD  REZ       2W                                                   0484.000
IPU.NEW  M.PSDGEN  IPU.1,DIR,UEI,UNMAP                          EIPU360A0485.000
*PU.NEW  GEN       1/1,4/0,1/1,2/0,5/0,19/W(IPU.1)         2111 EIPU360A0486.000
*        GEN       2/0,12/0,1/0,1/0,1/0,1/0,12/0,2/0       2111 EIPU360A0487.000
*                   *            *   *   *                              0488.000
*                   *            *   *   *                              0489.000
*                   *            *   *   *49, NEW BLOCK STATE-BEI       0490.000
*                   *            *   *48, LOAD NEW BLOCK STATE          0491.000
*                   *            *47,RETAIN OLD MAP                     0492.000
*                   *32-33, MAP MODE (UNMAPPED)                         0493.000
*                                                                       0494.000
IPU.ST1  DATAW     0               ICB STATUS                           0495.000
IPU.ST2  DATAW     0               ICB STATUS                           0496.000
         BOUND     1F              FILE BOUND RMS-II MAILBOX    E2BIP35 0497.000
RMS.MBOX REZ       1F              MUST BE 8W AFTER IPU.ICB     E2BIP35 0498.000
************************************************************************0499.000
*                                                                       0500.000
*        DISCOVER REASON FOR TRAP                                       0501.000
*                                                                       0502.000
************************************************************************0503.000
*                                                                       0504.000
*        IF THE HEAD CELL COUNT (C.CIPU) = 0 THE CPU IS INDICATING THAT 0505.000
*        THERE IS PROBABLE CAUSE FOR THE IPU TO ATTEMPT TO SCHEDULE A   0506.000
*        TASK VIA THE 'HALT' INSTRUCTION, TO TRAP THE CPU IN H.CPU.     0507.000
*                                                                       0508.000
*        IF THE HEAD CELL COUNT (C.CIPU) > 0 AND THE OLD PSD POINTS     0509.000
*        TO THE ADDRESS CONTAINING THE 'HALT' INSTRUCTION THEN THE      0510.000
*        CPU IS ALLOWING THE IPU TO EXECUTE THE TASK LINKED TO THE      0511.000
*        CURRENT IPU HEAD CELL, C.CIPU.                                 0512.000
*                                                                       0513.000
*        IF THE HEAD CELL COUNT (C.CIPU) > 0 AND THE OLD PSD IS         0514.000
*        WITHIN THIS HANDLER THEN THE TASK                              0515.000
*        WAS IN THE PROCESS OF TRAPPING THE CPU. IGNORE THIS TRAP AND   0516.000
*        ALLOW THE EXISTING TRAP TO FINISH.                             0517.000
*                                                                       0518.000
*        IF THE HEAD CELL COUNT (C.CIPU) > 0 BUT THE OLD PSD DOES       0519.000
*        NOT POINT TO THE ADDRESS CONTAINING THE 'HALT' INSTRUCTION     0520.000
*        THEN THE CPU IS REQUESTING THE IPU TO TERMINATE THE EXECUTION  0521.000
*        OF THE CURRENT TASK IN FAVOR OF SCHEDULING A NEW TASK          0522.000
*                                                                       0523.000
************************************************************************0524.000
*                                                                       0525.000
IPU.1    EQU       $                                                #T# 0526.000
*        SBM       C.ICSIPU,C.BIT     TELL CPU TO HOLD OFF 3201 E2BIP35 0527.000
         SBM       C.IPUCSI,C.IPUFLG  INHIB IPU CONTEXT SWITCH  E2BIP35 0528.000
