74 lines
2.6 KiB
Plaintext
74 lines
2.6 KiB
Plaintext
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DEFINITION MODULE BitByteOps;
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(* Bitwise operations on bytes.
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Bits in bytes are numbered from 0 to 7 *)
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FROM SYSTEM IMPORT BYTE;
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PROCEDURE GetBits (source : BYTE;
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firstBit, lastBit : CARDINAL): BYTE;
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(* Extracts the bits of source from firstBit to lastBit and returns
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them as a byte in which bit 0 correspond to the firstBit of the
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source. *)
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PROCEDURE SetBits (VAR byte : BYTE;
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firstBit, lastBit: CARDINAL;
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pattern : BYTE);
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(* Masks byte with pattern from firstBit to lastBit. The first
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(lastBit - firstBit + 1 of pattern are used, with leading zeros
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if necessary.
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Examples : To set the bits to 1, the pattern 0FFH should be passed,
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and to set the bits to 0, the pattern 0 should be passed. *)
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PROCEDURE ByteAnd (left, right : BYTE): BYTE;
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(* Bitwise AND *)
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PROCEDURE ByteOr (left, right : BYTE): BYTE;
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(* Bitwise OR *)
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PROCEDURE ByteXor (left, right : BYTE): BYTE;
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(* Bitwise XOR *)
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PROCEDURE ByteNot (byte : BYTE): BYTE;
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(* Bitwise complement to 1 *)
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PROCEDURE ByteShr (byte : BYTE;
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count : CARDINAL): BYTE;
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(* Shift Logical Right
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shifts the bits in byte to the right by the number of bits specified
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in count. Zeros are shifted in on the left. *)
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PROCEDURE ByteSar (byte : BYTE;
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count : CARDINAL): BYTE;
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(* Shift Arithmetic Right
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shifts the bits in byte to the right by the number of bits specified
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in count. Bits equal to the original high order bit are shifted in
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on the left, preserving the sign of the original value. *)
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PROCEDURE ByteShl (byte : BYTE;
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count : CARDINAL): BYTE;
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(* Shift Left
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shifts the bits in byte to the left by the number of bits specified
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in count. Zeros are shifted in on the right. *)
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PROCEDURE ByteRor (byte : BYTE;
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count : CARDINAL): BYTE;
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(* Rotate Right
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rotates byte right by the number of bits specified in count *)
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PROCEDURE ByteRol (byte : BYTE;
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count : CARDINAL): BYTE;
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(* Rotate Left
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rotates byte left by the number of bits specified in count *)
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PROCEDURE HighNibble (byte : BYTE): BYTE;
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(* Returns the high order nibble (4 bits) value of byte *)
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PROCEDURE LowNibble (byte : BYTE): BYTE;
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(* Returns the low order nibble (4 bits) value of byte *)
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PROCEDURE Swap (VAR byte : BYTE);
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(* Swaps the high and low order nibble values of byte *)
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END BitByteOps.
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