Reference Guide

Chapter 2 29

Program Structure

Expressions

frame (that is, .CALLINFO speciﬁed FRAME > 8191) or .CALLINFO

speciﬁed .ALLOCA_FRAME. In those two cases, %previous_sp is the

same as %r3, and %r3 is set up by the .ENTER pseudo-operation.

Expressions

Arithmetic expressions are often valuable in writing assembly code. The

Assembler allows expressions involving integer constants, symbolic

constants, and symbolic addresses. These terms can be combined with

the standard arithmetic operators shown in “Standard Arithmetic

Operators” on page 29 or with bit-wise operators shown in “Bit-Wise

Operators” on page 29.

Table 2-8 Standard Arithmetic Operators

The multiplication and division operators have precedence over addition

and subtraction. That is, multiplications and divisions are performed

ﬁrst from left to right, then additions and subtractions are performed

from left to right. Therefore, the expression 2+3*4 evaluates to 14.

Table 2-9 Bit-Wise Operators

Operator Operation

+ Integer addition

- Integer subtraction

* Integer multiplication

/ Integer division (result is truncated)

Operator Operation

| Logical OR

& Logical AND

~ Unary logical complement (tilde)