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MVN: Difference between revisions

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(added parameter descriptions)
(added execution sequence)
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* the first operand byte specifies the destination bank the block will be in
* the first operand byte specifies the destination bank the block will be in
* the second operand byte specifies the source bank the block starts out in
* the second operand byte specifies the source bank the block starts out in
=== Execution Sequence ===
The following loop is repeated until the value in the C double accumulator is $FFFF:
* one byte is copied from the address in X to the address in Y
* both X and Y are incremented
* C is decremented


=== See Also ===
=== See Also ===

Revision as of 04:11, 18 June 2023

MVN (Block Move Negative) is a 65c816 instruction that copies a contiguous block of memory. It is intended to copy a block from a higher address to a lower address (moving it in the negative direction).

In Eyes & Lichty, the "N" in the mnemonic stands for "Next" not "Negative."

mvn.png
Basic Info
Addressing Mode Opcode Length Speed
block move 54 3 bytes 7 cycles per byte moved
Flags Clobbered
N V M X D I Z C
. . . . . . . .

Parameters

  • the X index register specifies the starting (lowest) source address of the block
  • the Y index register specifies the starting (lowest) destination address of the block
  • the C double accumulator specifies the length of the block in bytes minus one
  • the first operand byte specifies the destination bank the block will be in
  • the second operand byte specifies the source bank the block starts out in

Execution Sequence

The following loop is repeated until the value in the C double accumulator is $FFFF:

  • one byte is copied from the address in X to the address in Y
  • both X and Y are incremented
  • C is decremented

See Also

External Links