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Blezl, Branch on less than or equal to zero likely – NEC Network Controller uPD98502 User Manual

Page 457

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APPENDIX A MIPS III INSTRUCTION SET DETAILS

Preliminary User’s Manual S15543EJ1V0UM

457

BLEZL

Branch On Less Than Or Equal To Zero Likely

BLEZL

rs

BLEZL

0 1 0 1 1 0

0

0 0 0 0 0

offset

31

26 25

21 20

16 15

0

6

5

5

16

Format:

BLEZL 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. The contents of general register rs is compared to zero. If the

contents of general register

rs are zero or smaller than zero, 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]

31

= 1) or (GPR [rs] = 0

32

)

T+1: if condition then

PC

← PC + target

else

NullifyCurrentInstruction

endif

64

T:

target

← (offset

15

)

46

|| offset || 0

2

condition

← (GPR [rs]

63

= 1) or (GPR [rs] = 0

64

)

T+1: if condition then

PC

← PC + target

else

NullifyCurrentInstruction

endif

Exceptions:

None