Specifications

Description
Sign-extends the 16-bit immediate value IMM16 to 32 bits and
compares it to the value of rA. If rA != σ(IMM16), then cmpnei
stores 1 to rB; otherwise stores 0 to rB.
Usage
cmpnei performs the != operation of the C programming
language.
Exceptions
None
Instruction Type
I
Instruction Fields
A = Register index of operand rA
B = Register index of operand rB
IMM16 = 16-bit signed immediate value
Bit Fields
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
A B IMM16
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
IMM16 0x18
custom
Instruction
custom instruction
Operation
if c == 1
then rC ← f
N
(rA, rB, A, B, C)
else Ø ← f
N
(rA, rB, A, B, C)
Assembler Syntax
custom N, xC, xA, xB
Where xA means either general purpose register rA, or custom
register cA.
Example
custom 0, c6, r7, r8
Description
The custom opcode provides access to up to 256 custom
instructions allowed by the Nios II architecture. The function
implemented by a custom instruction is user-defined and is
specified with the Nios_II Processor parameter editor in Qsys.
The 8-bit immediate N field specifies which custom instruction
to use. Custom instructions can use up to two parameters, xA
and xB, and can optionally write the result to a register xC.
8-34
custom
NII51017
2015.04.02
Altera Corporation
Instruction Set Reference
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