We've just updated MediaWiki and its underlying software. If anything doesn't look or work quite right, please mention it to us. --RanAS

MVP: Difference between revisions

From SnesLab
Jump to: navigation, search
(→‎External Links: Clark link)
(emulation mode)
Line 40: Line 40:


In [[Eyes & Lichty]], the "P" in the mnemonic stands for "Previous" not "Positive."
In [[Eyes & Lichty]], the "P" in the mnemonic stands for "Previous" not "Positive."
MVP works even in [[emulation mode]].


=== Parameters ===
=== Parameters ===

Revision as of 22:35, 22 July 2024

Basic Info
Addressing Mode Opcode Length Speed
Block Move 44 3 bytes 7 cycles per byte moved
mvp.png
Flags Affected
N V M X D I Z C
. . . . . . . .

MVP (Block Move Positive) is a 65c816 instruction that copies a contiguous block of memory. It is intended to copy a block from a lower address to a higher address (moving it in the positive direction). No flags are affected.

In Eyes & Lichty, the "P" in the mnemonic stands for "Previous" not "Positive."

MVP works even in emulation mode.

Parameters

  • the X index register specifies the ending (highest) source address of the block
  • the Y index register specifies the ending (highest) 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 decremented
  • C is decremented

If interrupted, the current byte finishes copying before servicing the interrupt.

See Also

External Links