Specifications

Table 3-48: Conditional Branch Instructions
Instruction Description
bge
bgeu
bgt
bgtu
ble
bleu
blt
bltu
beq
bne
These instructions provide relative branches that compare two register values
and branch if the expression is true. Refer to the "Comparison Instructions"
section of this chapter for a description of the relational operations
implemented.
Related Information
Comparison Instructions on page 3-62
Other Control Instructions
Table 3-49: Other Control Instructions
Instruction Description
trap
eret
The trap and eret instructions generate and return from exceptions. These instruc‐
tions are similar to the call/ret pair, but are used for exceptions. trap saves the
status register in the estatus register, saves the return address in the ea register, and
then transfers execution to the general exception handler. eret returns from exception
processing by restoring status from estatus, and executing the instruction specified
by the address in ea.
break
bret
The break and bret instructions generate and return from breaks. break and bret are
used exclusively by software debugging tools. Programmers never use these instruc‐
tions in application code.
rdctl
wrctl
These instructions read and write control registers, such as the status register. The
value is read from or stored to a general-purpose register.
flushd
flushda
flushi
initd
initda
initi
These instructions are used to manage the data and instruction cache memories.
flushp This instruction flushes all prefetched instructions from the pipeline. This is necessary
before jumping to recently-modified instruction memory.
sync This instruction ensures that all previously-issued operations have completed before
allowing execution of subsequent load and store operations.
3-64
Other Control Instructions
NII51003
2015.04.02
Altera Corporation
Programming Model
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