42 lines
1.2 KiB
Plaintext
42 lines
1.2 KiB
Plaintext
.ifndef INCLUDE_PARITY
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INCLUDE_PARITY = 1
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;;********************************************************************************
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;; @file
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;; @brief Macros for calculating parity
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;; @ingroup libs
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;;********************************************************************************
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.import count_set_bits
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;;********************************************************************************
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;; @macro Calculate even parity
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;; @modifies A, X, Y
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;; @returns A: 0 - even number of set bits, 1 - uneven number of set bits
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;; @returns Y: The number of set bits in the byte
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;;********************************************************************************
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.macro CalculateEvenParity
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jsr count_set_bits
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tya
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and #1
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.endmacro
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;;********************************************************************************
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;; @macro Calculate odd parity
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;; @details
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;; Count the number of set bits in Y.
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;;
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;; @modifies A, X, Y
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;; @returns A: 1 - even number of set bits, 0 - uneven number of set bits
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;; @returns Y: The number of set bits in the byte
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;;********************************************************************************
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.macro CalculateOddParity
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jsr count_set_bits
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tya
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and #1
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eor #1
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.endmacro
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.endif ; guard
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