bit, sbit

bit, sbit Accessor

Syntax:

bit bit-array &rest subscripts → bit

sbit bit-array &rest subscripts → bit

(setf (bit bit-array &rest subscripts**)** new-bit**)**

(setf (sbit bit-array &rest subscripts**)** new-bit**)**

Arguments and Values:

bit-array—for bit, a bit array; for sbit, a simple bit array.

subscripts—a list of valid array indices for the bit-array.

bit—a bit.

Description:

bit and sbit access the bit-array element specified by subscripts.

These functions ignore the fill pointer when accessing elements.

Examples:

 
(bit (setq ba (make-array 8 
:element-type ’bit 
:initial-element 1)) 
\3) → 1 
(setf (bit ba 3) 0) → 0 
(bit ba 3) → 0 
(sbit ba 5) → 1 
(setf (sbit ba 5) 1) → 1 
 
 
(sbit ba 5) → 1 

See Also:

aref, Section 3.2.1 (Compiler Terminology)

Notes:

bit and sbit are like aref except that they require arrays to be a bit array and a simple bit array, respectively.

bit and sbit, unlike char and schar, allow the first argument to be an array of any rank.

^{bit-and, bit-andc1, bit-andc2, bit-eqv, bit-ior, bit} nand, bit-nor, bit-not, bit-orc1, bit-orc2, bit-xor Function

Syntax:

bit-and bit-array1 bit-array2 &optional opt-arg → resulting-bit-array

bit-andc1 bit-array1 bit-array2 &optional opt-arg → resulting-bit-array

bit-andc2 bit-array1 bit-array2 &optional opt-arg → resulting-bit-array

bit-eqv bit-array1 bit-array2 &optional opt-arg → resulting-bit-array

bit-ior bit-array1 bit-array2 &optional opt-arg → resulting-bit-array

bit-nand bit-array1 bit-array2 &optional opt-arg → resulting-bit-array

bit-nor bit-array1 bit-array2 &optional opt-arg → resulting-bit-array

bit-orc1 bit-array1 bit-array2 &optional opt-arg → resulting-bit-array

bit-orc2 bit-array1 bit-array2 &optional opt-arg → resulting-bit-array

bit-xor bit-array1 bit-array2 &optional opt-arg → resulting-bit-array

bit-not bit-array &optional opt-arg → resulting-bit-array

Arguments and Values:

bit-array, bit-array1, bit-array2—a bit array.

Opt-arg—a bit array, or t, or nil. The default is nil.

Bit-array, bit-array1, bit-array2, and opt-arg (if an array) must all be of the same rank and dimensions.

resulting-bit-array—a bit array.

Description:

These functions perform bit-wise logical operations on bit-array1 and bit-array2 and return an array of matching rank and dimensions, such that any given bit of the result is produced by operating on corresponding bits from each of the arguments.

In the case of bit-not, an array of rank and dimensions matching bit-array is returned that contains a copy of bit-array with all the bits inverted.

If opt-arg is of type (array bit) the contents of the result are destructively placed into opt-arg. If opt-arg is the symbol t, bit-array or bit-array1 is replaced with the result; if opt-arg is nil or omitted, a new array is created to contain the result.

Figure 15–4 indicates the logical operation performed by each of the functions.

|Function Operation|

| :- |

|

bit-and and

bit-eqv equivalence (exclusive nor)

bit-not complement

bit-ior inclusive or

bit-xor exclusive or

bit-nand complement of bit-array1 and bit-array2

bit-nor complement of bit-array1 or bit-array2

bit-andc1 and complement of bit-array1 with bit-array2

bit-andc2 and bit-array1 with complement of bit-array2

bit-orc1 or complement of bit-array1 with bit-array2

bit-orc2 or bit-array1 with complement of bit-array2

|

Figure 15–4. Bit-wise Logical Operations on Bit Arrays

Examples:

(bit-and (setq ba #\*11101010) #\*01101011) → #\*01101010 
(bit-and #\*1100 #\*1010) → #\*1000 
(bit-andc1 #\*1100 #\*1010) → #\*0010 
(setq rba (bit-andc2 ba #\*00110011 t)) → #\*11001000 
(eq rba ba) → true 
(bit-not (setq ba #\*11101010)) → #\*00010101 
(setq rba (bit-not ba 
		   (setq tba (make-array 8 
					 :element-type ’bit)))) 
→ #\*00010101 
(equal rba tba) → true 
(bit-xor #\*1100 #\*1010) → #\*0110 

See Also:

lognot, logand

Expanded Reference: bit, sbit

tip

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(bit, sbit )