Power ISA™ Version 2.03 - Power.org

Version 2.03
SPR(x) Special Purpose Register x
TRAP Invoke the system trap handler
characterization
Reference to the setting of status bits, in a
standard way that is explained in the text
undefined An undefined value.
CIA Current Instruction Address, which is the
64-bit address of the instruction being
described by a sequence of RTL. Used by
relative branches to set the Next Instruction
Address (NIA), and by Branch instructions
with LK=1 to set the Link Register.
Does not correspond to any architected
register.
NIA Next Instruction Address, which is the
64-bit address of the next instruction to be
executed. For a successful branch, the
next instruction address is the branch target
address: in RTL, this is indicated by
assigning a value to NIA. For other
instructions that cause non-sequential
instruction fetching (see Book III), the RTL
is similar. For instructions that do not
branch, and do not otherwise cause
instruction fetching to be non-sequential,
the next instruction address is CIA+4 (VLE
behavior is different; see Book VLE). Does
not correspond to any architected register.
if... then... else...
Conditional execution, indenting shows
range; else is optional.
do Do loop, indenting shows range. “To” and/
or “by” clauses specify incrementing an
iteration variable, and a “while” clause
gives termination conditions.
leave Leave innermost do loop, or do loop
described in leave statement.
for For loop, indenting shows range. Clause
after “for” specifies the entities for which to
execute the body of the loop.
The precedence rules for RTL operators are summarized
in Table 1. Operators higher in the table are
applied before those lower in the table. Operators at
the same level in the table associate from left to right,
from right to left, or not at all, as shown. (For example,
- associates from left to right, so a-b-c = (a-b)-c.)
Parentheses are used to override the evaluation order
implied by the table or to increase clarity; parenthesized
expressions are evaluated before serving as
operands.
Table 1: Operator precedence
Operators
Associativity
+, -, left to right
|| left to right
=, ≠, , ≥,< u , > u , ? left to right
&, ⊕, ≡
left to right
| left to right
: (range) none
, iea
none
Table 1: Operator precedence
Operators
Associativity
subscript, function evaluation left to right
pre-superscript (replication),
right to left
post-superscript (exponentiation)
unary -, ¬
right to left
×, ÷ left to right
Chapter 1. Introduction
7