Intel AEDIT-86 manual Shift/Rotate Operators

CALC ColDlDand AEDIT-86 User's Guide

second occurrence of that character signifies the right end of the string. To prevent ambiguity, the following characters may not serve as string delimiters: letters, digits, blank, and tab.

A natural delimiter choice is a quotation mark. However, if the string constant includes a quotation mark, a different character, one that does not appear in the string, should be used as the delimiter.

The case of the letters within the string is preserved.

7.5 Operators

Syntactically, operators are divided into two groups: unary operators and binary operators. From the functional point of view, the operators are divided into the following groups: logical operators, relational operators, shift/rotate operators, and arithmetic operators. Table 7-1 partially reflects this partition.

Table 7-1 lists all the CALC command operators with a brief description of the semantics of each operator. Following are more detailed descriptions of the nontrivial operators:

1.- and ' (1 's complement) have the same meaning. The duplicate notation prevents possible difficulties on terminals where one of these characters may have a special meaning. 1's complement means for every 0 bit, a 1 bit is returned and vice versa.

2.! and # :

The POS operator (!) is defined as follows: If number > 0 then return true ( -1 ) else return false (0).

The NEG operator (#) is defined as follows: If number > 0 then return false (0)

else return true ( -1 ).

3.\ (modulo division) returns the remainder of an integer division, for example, 7

\4 = 3; 16 \ 4 = O.

4.1\ (XOR) returns true only if one operand is true and the other is false; other- wise it returns false. This is done for each bit in the argument, for example, 51\1 =4.

7.5.1 Shift/Rotate Operators

In the shift/rotate operations, the left operand is handled as a pattern of 32 bits. It is moved to the right or to the left by the number of bits specified by the right operand.

In a shift, bits moved off one end of the pattern are lost, and 0 bits or 1 bits are moved into the pattern from the other end. In a rotate, bits moved off of one end move onto the other end.

SAL and SAR are algebraic shift operators. This means that the high order bit is the sign bit, and there is no shift of bits between the sign and the rest of the number. In a left shift (SAL), 0 bits move into the pattern from the right. In a right shift (SAR), either 0 bits (if pattern is positive) or 1 bits (if pattern is negative) move into the pattern from the left.

In every shift/rotate operation, the right operand (count) is always taken as modulo

256.

7-4