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

Branch and Unmask Long (BUL) (5010 Processor Module Model E only)0 5 8 16 31Op codeRModifierAddress0 1 0 1I I I0I0 01010 0 0 0 1 0 0 0I I I I I I I 1 1 1III III III5 0 0 8 X X X XThe branch and unmask long instruction branches to another storage location specifiedby the contents of the address field. The BUL instruction is unconditional; the branch isalways taken because it is not based upon the results of a condition or test.The contents of the IAR are replaced by the contents of the address field and becomethe location branched to. The contents of the IAR are not saved.The summary mask is turned off, thus returning interrupt servicing to levels enabled inthe interruption mask register. Interruption of the program may occur before, or immediatelyafter, the next sequential instruction.The R field is unused and must be set to 0's. The branch and unmask long instructiondoes not change the carry, overflow, and result indicators.If this instruction is issued on a 5010 Processor Module model .A or B, it is treated asa PBALL instruction. (See the description of the PBALL instruction earlier in this chapter.)