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

Alter Protect Key (APK)0 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA0 0 0 0 1 XX X 0 0 0 0 0 0 0 0 0 0 0 1 if * * *I I I I 1 I I I 1 1 I I I I 1 1 1 1 1 I I I I I'Vs.\ „.•••••■••■•••••••„,.■•■■, ••■••••■,•■••■,0 8-F 0 0 1 0 0 0Bits 13 through 15 of a register, or the accumulator if R = 000, are loaded into the protectkey for the current level. This instruction also enables the storage protect mechanism, whichif previously enabled remains enabled. The result indicators are not changed but the carryand overflow indicators are reset to 0.Example:0 5 8 11 16 20 26 31APK instructionOp code R Fun Zeros Mod DA MA0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 01 I 1 I II II I I I I III 11 1 I 1 11111`.■••■•,■••■•, ••••••■.,,11r,0 A 0 0 1 0 0 0Protect key register Index register 20 15 0 15APK instructionis fetched111111111111111■•••••••,,..N.,X X X XO 0 0 0 0 0 0 0 0 0 0 0 011 1 01 1 1 I I 1 1 1 I 1 1 1 1 1 IO 0 0 60 15 0 15After APKinstructionexecutionKey0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0O 0 0 0 0 0 0 0 0 0 0 0 0 1 1 011111111111111!•••••••••■,,onlia, ••■•••••••,.,■■■•••" ••■•■•••••,•••■■•••0 0 0 6 O 0 0 6Processor Instructions 4-53