HLASM - BNMR = Branch on Not Mixed / Minus Register

The opcode of the BNMR extended mnemonic is X'07' with mask B'1011'.

The mask is the third hex digit of the instruction, and - though this is uncommon - can be regarded as the third hex digit of the opcode as well.

BNMR is used both for Branch on Not Minus Register and for Branch on Not Mixed Register


  1. Perform a branch if the condition code is not 1 or B'01', meaning either "minus" or "mixed".
  2. Condition code 1 may occur after bit operations, such as TM. After boolean operations (and, or, exclusive or) condition code 1 means mixed or all ones.
  3. Condition code 1 may also occur after signed binary calculations, such as AR. Do not use after multiplication or division, since these do not set the condition code.


  1. Register holding the destination address.


  1. The processor uses the PSW's two-bit condition code as an index into the 4-bit condition mask.
  2. If the selected mask-bit is one, then it branches to the address specified in the second argument. If the bit is zero, then the processor continues with the next instruction.
  3. The condition code does not change.

Special Cases

  1. If the destination address is in register 0 no branch will be taken.

Related Instructions

  1. BNLR is a synonym for the BNMR mnemonic.
  2. BNM branches to a location that is directly addressable in base-displacement form.
  3. BCR is the real instruction associated with this extended mnemonic.


  1. All hardware supports the BNMR instruction.


  1. The PSW's Amode setting determines how many bits are used for the destination address.


         YREGS                          * Define register names
         TM    FIELD,MASK               * Check bit settings
         BNMR  R14                      * All ones or all zeros
         AR    R6,R1                    * Add to total
         BNMR  R14                      * Overflow, zero,or plus: return

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