IPR-NIOS Altera, IPR-NIOS Datasheet - Page 268

• Manufacturer Part Number: IPR-NIOS
• Description: IP NIOS II MEGACORE RENEW
• Manufacturer: Altera
• Type: MegaCorer

Specifications of IPR-NIOS

• License: Renewal License
• Lead Free Status / RoHS Status: Not applicable / Not applicable

8–82
rdprs
Nios II Processor Reference Handbook
Operation:
Assembler Syntax:
Example:
Description:
Usage:
Exceptions:
Instruction Type:
Instruction Fields:
31
30
29
A
28
27
26
25
24
B
rB ← prs.rA + σ (IMM16)
rdprs rB, rA, IMM16
rdprs r6, r7, 0
Sign-extends the 16-bit immediate value IMM16 to 32 bits, and adds it to the value of rA from
the previous register set. Places the result in rB in the current register set.
The previous register set is specified by status.PRS. By default, status.PRS indicates
the register set in use before an exception, such as an external interrupt, caused a
register set change.
To read from an arbitrary register set, software can insert the desired register set number in
status.PRS prior to executing rdprs.
If shadow register sets are not implemented on the Nios II core, rdprs is an illegal instruction.
Supervisor-only instruction
Illegal instruction
I
A = Register index of operand rA
B = Register index of operand rB
IMM16 = 16-bit signed immediate value
23
22
21
20
19
18
17
16
15
IMM16
14
13
12
11
read from previous register set
10
9
8
Chapter 8: Instruction Set Reference
December 2010 Altera Corporation
7
6
5
Instruction Set Reference
4
0x38
3
2
1
0