Block Move Addressing

Two instructions use Block Move Addressing on the 65c816:

• MVP (opcode 44)
• MVN (opcode 54)

The total number of bytes copied is the value in the C accumulator plus one. If a block move is interrupted, the current byte copy is completed, then the interrupt is serviced.

When the copying is complete:

• the accumulator will contain the value $FFFF.
• both index registers will point to the byte one past the end of the blocks they were pointing to
• if the source and destination blocks do not overlap, the source block is still intact

Syntax

Asar:

MVN srds

References

• Eyes & Lichty, page 388: https://archive.org/details/0893037893ProgrammingThe65816/page/388
• "Block Moves" on page 103, lbid: https://archive.org/details/0893037893ProgrammingThe65816/page/103
• section 3.5.9 of 65c816 datasheet, https://westerndesigncenter.com/wdc/documentation/w65c816s.pdf