Click above to get retro games delivered to your door ever month!

SYNTAX      [<LABEL>] BV <pma>[,{ind}[,<next ARP>]]

OPERANDS    0 . pma . 65535; 0 . next ARP . 7.

EXECUTION   If overflow OV status bit = 1:
            then pma . PC and 0 . OV; else (PC) + 2 . PC.
            Modify AR(ARP) and ARP as specified.
            Affects OV; affected by OV.

DESCRIPTION The current auxiliary register and ARP are modified as
            specified. If the OV (overflow flag) is set, then control
            passes to the designated program memory address (pma) and the
            overflow flag is cleared; otherwise, control passes to the
            next instruction. Note that no AR or ARP modification occurs
            if nothing is specified in those fields. Pma can be either a
            symbolic or numeric address.

WORDS       2

ENCODING    15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0
            +-----------------------------------------------+
            |1  1  1  1  0  0  0  0  1| see indirect fields |
            +-----------------------------------------------+
            +-----------------------------------------------+
            |           program memory address              |
            +-----------------------------------------------+

CYCLES

            +----------------------------------------------------+
            |       Cycle Timings for a Single Instruction       |
            |----------------------------------------------------|
            |  PI/DI |  PI/DE |  PE/DI |  PE/DE  | PR/DI | PR/DE |
            |-----------------+------------------+-------+-------|
      '20   |2 (br int-to-int)| 2+p (int-to-ext) |   _   |   _   |
            | 2+p (ext-to-int)| 2+2p (ext-to-ext)|       |       |
            |----------------------------------------------------|
      'C25  | True Conditions:                                   |
            |----------------------------------------------------|
            |              Destination on-chip RAM:              |
            |----------------------------------------------------|
            |    2   |   2    |  2+2p  |  2+2p   |   2   |   2   |
            |----------------------------------------------------|
            |              Destination on-chip ROM:              |
            |----------------------------------------------------|
            |    3   |   3    |  3+2p  |  3+2p   |   3   |   3   |
            |----------------------------------------------------|
            |            Destination external memory:            |
            |----------------------------------------------------|
            |   3+p  |  3+p   |  3+3p  |  3+3p   |  3+p  |  3+p  |
            |----------------------------------------------------|
            |  False Condition:                                  |
            |----------------------------------------------------|
            |               Destination anywhere:                |
            |----------------------------------------------------|
            |    2   |    2   |  2+2p  |  2+2p   |   2   |   2   |
            |----------------------------------------------------|
            |       Cycle Timings for a Repeat Instruction       |
            |----------------------------------------------------|
      '20   |          not repeatable            |   -   |   -   |
            |----------------------------------------------------|
     'C25   |                     not repeatable                 |
            +----------------------------------------------------+



EXAMPLE     BV    PRG610      If an overflow has occurred since the
                              overflow flag was last cleared, then 610 is
                              loaded into the program counter. OV is
                              cleared.