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SYNTAX      [<LABEL>] TRAP

OPERANDS    None

EXECUTION   (PC) + 1 . stack
            30 . PC

DESCRIPTION The TRAP instruction is a software interrupt that transfers
            program control to program memory location 30 and pushes the
            program counter plus one on the hardware stack. The
            instruction at location 30 may contain a branch instruction
            to transfer control to the TRAP routine. Putting the PC + 1
            onto the stack enables an RET instruction to pop the return
            PC (points to the instruction after the TRAP) from the stack.

WORDS       1

ENCODING    15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0
            +-----------------------------------------------+
            |1  1  0  0  1  1  1  0  0  0  0  1  1  1  1  0 |
            +-----------------------------------------------+

CYCLES

            +-------------------------------------------------+
            |      Cycle Timings for a Single Instruction      |
            |-------------------------------------------------|
            | PI/DI | PI/DE | PE/DI |  PE/DE  | PR/DI | PR/DE |
            |-------+-------+-------+---------+-------+-------|
      '20   |   2   |   2   |  2+p  |   2+p   |   -   |   -   |
            |-------------------------------------------------|
      'C25  |            Destination on chip RAM:             |
            |-------------------------------------------------|
            |   2   |   2   |  2+p  |   2+p   |   2   |   2   |
            |-------------------------------------------------|
            |            Destination on chip ROM:             |
            |-------------------------------------------------|
            |   3   |   3   |  3+p  |   3+p   |   3   |   3   |
            |-------------------------------------------------|
            |          Destination external memory:           |
            |-------------------------------------------------|
            |  3+p  |  3+p  |  3+2p |  3+2p   |  3+p  |  3+p  |
            |-------------------------------------------------|
            |      Cycle Timings for a Repeat Instruction     |
            |-------------------------------------------------|
      '20   |         not repeatable          |   -   |   -   |
            |-------------------------------------------------|
     'C25   |                 not repeatable                  |
            +-------------------------------------------------+



EXAMPLE     TRAP              Control is passed to program memory location
                              30. PC + 1 is pushed onto the stack.