MicroBlaze Processor Reference Guide www.xilinx.com 81
UG081 (v6.0) June 1, 2006 1-800-255-7778
Instructions
R
bge
Branch if Greater or Equal
Description
Branch if rA is greater or equal to 0, to the instruction locatedin the offset value of rB. The
target of the branch will be the instruction at address PC + rB.
The mnemonic bged will set the D bit. The D bit determines whether there is a branch
delay slot or not. If the D bit is set, it means that there is a delay slot and the instruction
following thebranch (i.e.in the branch delay slot) is allowed tocomplete executionbefore
executingthe targetinstruction.If the Dbit isnot set, itmeans that thereis no delayslot, so
the instruction to be executed after the branch is the target instruction.
Pseudocode
If rA >= 0 then
PC
PC + rB
else
PC
PC + 4
if D = 1 then
allow following instruction to complete execution
Registers Altered
PC
Latency
1 cycle (if branch is not taken)
2 cycles (if branch is taken and the D bit is set)
3 cycles (if branch is taken and the D bit is not set)
Note
A delay slot must not be used by the following: IMM, branch, or break instructions. This
also applies to instructions causing recoverable exceptions (e.g. unalignement), when
hardware exceptions are enabled. Interrupts and external hardware breaks are deferred
until after the delay slot branch has been completed.
bge rA, rB Branch if Greater or Equal
bged rA, rB Branch if Greater or Equal with Delay
1 0 0 1 1 1 D 0 1 0 1 rA rB 0 0 0 0 0 0 0 0 0 0 0
0 6 11 16 21 31