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reg/lcmp - Rolling byte comparisons

CONTENTS

Synopsis
Description
Error Handling
Examples
See Also
Author

reg/lcmp write, #cmp1, #cmp2
reg/lcmp write, #cmp1, #cmp2, #mask

reg/rcmp write, #cmp1, #cmp2
reg/rcmp write, #cmp1, #cmp2, #mask

Performs a byte-by-byte comparison of two 32-bit integers (raw indices) provided in the cmp1 and cmp2 arguments, returning the number of octets that matched in the write argument.

The reg/lcmp instruction performs a rolling left comparison of the two indices. Each octet is compared starting at the left-most octet, and the number of matching octets is returned in the write argument.

The reg/rcmp instruction performs a rolling right comparison of the two indices. Each octet is compared starting at the right-most octet, and the number of matching octets is returned in the write argument.

If a mask argument is provided with either instruction, it is applied using a bitwise AND operation to both cmp1 and cmp2 values before the comparison begins.

A runtime error is generated if a write argument is not a register or if a cmp1, cmp2 or mask argument is not a number (raw index) nor a register containing one.

reg/lcmp P0, #0x11223344, #0x11223355
	Returns the value 3 in register P0, because the left-most three octets match in the given arguments.
reg/rcmp PUSH, #0xa2580913, #0x10580913, #0xffffff
	Pushes the value 4 to the stack, because the right-most four octets all match in the given arguments after the mask is applied.

pal_commands(5), pal_registers(5), pal_indices(5), op_mask(5), op_swap(5),
PROSE Assembly Language at prose.sourceforge.net.

Copyright (c) 2002-2011 Mark R. Bannister <cambridge@users.sourceforge.net>.

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