NEC uPD98502 Network Cables User Manual


 
APPENDIX A MIPS III INSTRUCTION SET DETAILS
Preliminary Users Manual S15543EJ1V0UM
451
BGEZAL
Branch On Greater Than Or Equal To Zero And Link
BGEZAL
rs
REGIMM
0 0 0 0 0 1
BGEZAL
1 0 0 0 1
offset
31 26 25 21 20 16 15 0
655 16
Format:
BGEZAL rs, offset
Description:
A branch target address is computed from the sum of the address of the instruction in the delay slot and the 16-bit
offset,
shifted left two bits and sign-extended. Unconditionally, the address of the instruction after the delay slot is
placed in the link register,
r31
. If the contents of general register
rs
are zero or greater when compared to zero,
then the program branches to the target address, with a delay of one instruction.
General register
rs
may not be general register
r31
, because such an instruction is not restartable. An attempt to
execute this instruction is not trapped, however.
Operation:
32 T:
target (offset
15
)
14
|| offset || 0
2
condition (GPR [rs]
31
= 0)
GPR [31] PC + 8
T+1: if condition then
PC PC + target
endif
64 T:
target (offset15
)
46
|| offset || 0
2
condition (GPR [rs]
63
= 0)
GPR [31] PC + 8
T+1: if condition then
PC PC + target
endif
Exceptions:
None