Table 3–7: Operators (Continued)

Operator

Meaning

 

 

Bit concatenation

{}

Indicates explicit operator precedence

(x)

Contents of memory location whose address is x

x <m:n>

Contents of bit field of x defined by bits n through m

x <m>

M’th bit of x

ACCESS(x,y)

Accessibility of the location whose address is x using the

 

access mode y. Returns a Boolean value TRUE if the

 

address is accessible, else FALSE.

AND

Logical product

ARITH_RIGHT_SHIFT(x,y)

Arithmetic right shift of first operand by the second oper-

 

and. Y is an unsigned shift value. Bit 63, the sign bit, is

 

copied into vacated bit positions and shifted out bits are

 

discarded.

BYTE_ZAP(x,y)

X is a quadword, y is an 8-bit vector in which each bit

 

corresponds to a byte of the result. The y bit to x byte cor-

 

respondence is y <n> x <8n+7:8n>. This correspon-

 

dence also exists between y and the result.

 

For each bit of y from n = 0 to 7, if y <n> is 0 then byte

 

<n> of x is copied to byte <n> of result, and if y <n> is 1

 

then byte <n> of result is forced to all zeros.

 

 

Instruction Formats 3–7

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Compaq ECQD2KCTE manual Bit concatenation