Altera Nios II Custom - Manual (Page 21)

Chapter 2: Software Interface 2–5
Custom Instruction Assembly Software Interface
January 2011 Altera Corporation Nios II Custom Instruction User Guide
Example 2–6 shows a call to a custom instruction with index 0. The input to the
instruction is the current contents of the Nios II processor registers r7 and r8 , and the
results are stored in the Nios II processor register r6 .
Example 2–7 shows a call to a custom instruction with index 3. The input to the
instruction is the current contents of the Nios II processor register r2 and the custom
register c4 , and the results are stored in custom register c1 .
Example 2–8 shows a call to a custom instruction with index 4. The input to the
instruction is the current contents of the custom register c9 and the Nios II processor
register r2 , and the results are stored in Nios II processor register r6 .
f For more information about the binary format of custom instructions, refer to the
Instruction Set Reference chapter of the Nios II Processor Reference Handbook.
Example 2–7. Assembly Language Call to Customer Instruction II
custom 3, c1, r2, c4
Example 2–8. Assembly Language Call to Customer Instruction III
custom 4, r6, c9, r2