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Bnel, Branch on not equal likely – NEC Network Controller uPD98502 User Manual

Page 463

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APPENDIX A MIPS III INSTRUCTION SET DETAILS

Preliminary User’s Manual S15543EJ1V0UM

463

BNEL

Branch On Not Equal Likely

BNEL

rs

BNEL

0 1 0 1 0 1

rt

offset

31

26 25

21 20

16 15

0

6

5

5

16

Format:

BNEL rs, rt, 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. The contents of general register rs and the contents of general

register

rt are compared. If the two registers are not equal, then the program branches to the target address, with

a delay of one instruction.

If the conditional branch is not taken, the instruction in the branch delay slot is nullified.

Operation:

32

T:

target

← (offset

15

)

14

|| offset || 0

2

condition

← (GPR [rs] ≠ GPR [rt])

T+1: if condition then

PC

← PC + target

else

NullifyCurrentInstruction

endif

64

T:

target

← (offset

15

)

46

|| offset || 0

2

condition

← (GPR [rs] ≠ GPR [rt])

T+1: if condition then

PC

← PC + target

else

NullifyCurrentInstruction

endif

Exceptions:

None