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Bgtz, Branch on greater than zero – NEC Network Controller uPD98502 User Manual

Page 454

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APPENDIX A MIPS III INSTRUCTION SET DETAILS

454

Preliminary User’s Manual S15543EJ1V0UM

BGTZ

Branch On Greater Than Zero

BGTZ

rs

BGTZ

0 0 0 1 1 1

0

0 0 0 0 0

offset

31

26 25

21 20

16 15

0

6

5

5

16

Format:

BGTZ 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. 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.

Operation:

32

T:

target

← (offset

15

)

14

|| offset || 0

2

condition

← (GPR [rs]

31

= 0) and (GPR [rs]

≠ 0

32

)

T+1: if condition then

PC

← PC + target

endif

64

T:

target

← (offset

15

)

46

|| offset || 0

2

condition

← (GPR [rs]

63

= 0) and (GPR [rs]

≠ 0

64

)

T+1: if condition then

PC

← PC + target

endif

Exceptions:

None