Operators. Freescale Semiconductor sc100

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SC_Assem.book Page 48 Thursday, September 23, 2004 10:44 AM

Expressions

Operators

Operators

Most assembler operators pertain to both floating-point and integer values. The assembler follows these rules:

• If both operands are integers, the result is an integer value.

• If both operands are floating point values, the result is a floating-point value.

• If one operand is a floating-point value and the other operand is an integer value, the assembler converts the integer to a floating-point value, then applies the operator.

The result is a floating-point value.

Table 3.2 explains assembler operators, noting those restricted to integer operands. The main use of the relational and logical operands is with the IF conditional-assembly directive, although you can use these operands in any expression.

Table 3.2 Assembler Operators

Type

Unary

Arithmetic +

-

/

*

!

Operator Description

+

-

~

%

Plus — Returns the positive value of its operand.

Minus — Returns the negative value of its operand.

One’s Complement — Return’s the one’s complement of its integer operand; cannot be used with floating-point operands.

Logical Negate — Returns an integer 1 if the value of its operand is 0; otherwise returns a 0. The result’s memory space attribute is N

Example: If symbol BUF has the value 0, !BUF has the value 1. If BUF has the value 1000, !BUF has the value 0.

Addition — Yields the sum of its operands.

Subtraction — Yields the difference between its operands.

Multiplication — Yields the product of its operands.

Division — Yields the quotient: the first operand divided by the second. For integer operands, the result is a truncated integer.

Mod — Yields the remainder of the first operand divided by the second. (If both operands are floating-point values and the divisor is 0.0, the result is the dividend.)

48 SC100 Assembler User Guide

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SC_Assem.book Page 49 Thursday, September 23, 2004 10:44 AM

Expressions

Operators

Table 3.2 Assembler Operators ( continued)

Type

Shift

Operator Description

<<

>>

Relational <

Bitwise

|

>

<=

>=

==

!=

&

^

Shift Left — For integer operands only. Shifts and zero fills the left operand to the left; the right operand specifies the number of bits to shift.

Shift Right — For integer operands only. Shifts the left operand to the right; the right operand specifies the number of bits to shift. Extends the sign bit.

Less Than — Returns integer 1 if the expression is true, integer 0 if the expression is false. The result’s memory space attribute is N.

Example: If D = 3 and E = 5, D < E = 1.

Greater Than — Returns integer 1 if the expression is true, integer 0 if the expression is false. The result’s memory space attribute is N.

Example: If D = 3 and E = 5, D > E = 0.

Less Than or Equal — Returns integer 1 if the expression is true, integer 0 if the expression is false. The result’s memory space attribute is N.

Greater Than or Equal — Returns integer 1 if the expression is true, integer 0 if the expression is false. The result’s memory space attribute is N.

Equal — Returns integer 1 if the expression is true, integer

0 if the expression is false. The result’s memory space attribute is N.

Not Equal — Returns integer 1 if the expression is false, integer 0 if the expression is true. The result’s memory space attribute is N.

AND — For integers only. Yields the bitwise AND function of its operands.

OR — For integers only. Yields the bitwise OR function of its operands.

Exclusive OR — For integers only. Yields the bitwise exclusive OR function of its operands.

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