IBM System/370 145 Reference Summary page 90

PTH end PTL contains the CPU Timer value that 11 decremented
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811 0 CKC Run
CKCLast ln111rvel
LV •s the lest interval value CKCPT IExt 271
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CKCSubmesk
Bit 1 PT Submask
8112 Error Bit
8113 Manuel Mode
Bit 4 CKC Interrupt
81t5 PT Interrupt
B1t6 Update Latch
Destination to counter was blocked
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CS registers
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