MVP: Difference between revisions

Revision as of 03:26, 18 June 2023

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).

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


Basic Info
Addressing Mode	Opcode	Length	Speed
block move	44	3 bytes	7 cycles per byte moved


Flags Clobbered
N	V	M	X	D	I	Z	C
.	.	.	.	.	.	.	.

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

External Links

Eyes & Lichty page on MVP: https://archive.org/details/0893037893ProgrammingThe65816/page/n494
Labiak page on MVP: https://archive.org/details/Programming_the_65816/page/n164
snes9x implementation of MVP: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L3077
undisbeliever on MVP: https://undisbeliever.net/snesdev/65816-opcodes.html#mvp-block-move-previous

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+=== 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
 === See Also ===