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Altera Corporation 25
GettingOverview
Overview
1
Table 16. Notation Details
Notation Meaning Notation Meaning
X ← Y X is written with Y X >> n The value X after being right-shifted n bit
positions
∅←e Expression e is evaluated, and the result
is discarded
X << n The value X after being left-shifted n bit
positions
RA One of the 32 visible registers, selected
by the 5-bit a-field of the instruction word
bn
X The n
th
byte (8-bit field) within the
full-width value X.
b0
X = X[7..0],
b1
X = X[15..8],
b2
X = X[23..16], and
b3
X = X[31..24]
RB One of the 32 visible registers, selected
by the 5-bit b-field of the instruction word
hn
X The n
th
half-word (16-bit field) within the
full-width value X.
h0
X = X[15..0],
h1
X = X[31..16]
RP One of the 4 pointer-enabled (P-type)
registers, selected by the 2-bit p-field of
the instruction word
X & Y Bitwise logical AND
IMMn An n-bit immediate value, embedded in
the instruction word
X | Y Bitwise logical OR
K The 11-bit value held in the K register. (K
can only be set by a PFX instruction)
X ⊕ Y Bitwise logical exclusive OR
0xnn.mm Hexadecimal notation (decimal points not
significant, added for clarity)
~X Bitwise logical NOT (one’s complement)
X : Y Bitwise-concatenation operator.
e.g.: (0x12 : 0x34) = 0x1234
|X| The absolute value of X
(i.e. –X if (X < 0), X otherwise).
{e1, e2} Conditional expression. Evaluates to e2
if previous instruction was PFX,
e1 otherwise
Mem32[X] The aligned 32-bit word value stored in
external memory, starting at byte address
X
σ(X) X after being sign-extended into a full
register-sized signed integer
Mem16[X] The aligned 16-bit half-word value stored
in external memory, starting at byte-
address X
X[n] The n
th
bit of X (n = 0 means LSB) align16(X) X & 0xFF.FE, which is the integer value X
forced into half-word alignment via
truncation
X[n..m] Consecutive bits n through m of X align32(X) X & 0xFF.FF.FF.FC, which is the integer
value X forced into full-word alignment via
truncation
C The C (carry) flag in the STATUS register
CTLk One of the 2047 control registers selected
by K