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CHAPTER 2 V
R
4120A
Preliminary User’s Manual S14767EJ1V0UM00
93
2.3.6 MIPS16 operation code bit encoding
This section describes encoding for major operation code and minor operation code. Table 2-26 shows bit
encoding of the MIPS16 major operation code. Tables 2-27 to 2-32 show bit encoding of the minor operation code.
The italic operation codes in the tables are instructions for the extended ISA.
Table 2-26. Bit Encoding of Major Operation Code (op)
Instruction
Bits
Instruction Bits
[
13:11
]
[
15:14
]
000
001
010
011
100
101
110
111
00
addiusp
Note 1
addiupc
Note 2
b
jal(x)
Note 3
beqz
bnez
SHIFT
ld
01
RRI-A
addiu8
Note 4
slti
sltiu
l8
li
cmpi
sd
10
lb
lh
lwsp
lw
lbu
lhu
lwpc
lwu
11
sb
sh
swsp
sw
RRR
RR
extend
l64
Notes 1.
addiusp : addiu rx, sp, immediate
addiupc : addiu rx, pc, immediate
jal(x)
: jal instruction and jalx instruction
addiu8 : aadiu rx, immediate
2.
3.
4.
Table 2-27. RR Minor Operation Code (RR-Type Instruction)
Instruction
Bits
Instruction Bits
[
2:0
]
[
4:3
]
000
001
010
011
100
101
110
111
00
j(al)r
Note 1
slt
sltu
sllv
break
srlv
srav
01
dsrl
Note 2
φ
cmp
neg
and
or
xor
not
10
mfhi
mflo
dsra
Note 2
dsllv
dsrlv
dsrav
11
mult
multu
div
divu
dmult
dmultu
ddiv
ddivu
Notes 1.
j(al)r: jr rx instruction (ry = 000)
jr ra instruction (ry = 001, rx = 000)
jalr ra, rx instruction (ry = 010)
dsrl and dsra use the rx register field to encode the shift count (8-digit shift for 0). In the case of the
extended version of these two instructions, the EXT-SHIFT64 format is used. Only these two RR
instructions can be extended.
2.
Remark
The symbols in the figures have the following meaning.
: Execution of operation code with an asterisk on the current V
R
4120A causes a reserved instruction
exception to be generated. This code is reserved for future extension.
φ
: Operation code with
φ
is invalid, but no reserved instruction exception is generated in the V
R
4120A.