Major CPU Design Steps Rochester Institute of Technology. Sign Extension Representing a MIPS instructions Encoded as 32-bit instruction words op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits ., Why are 'opcode' field and 'funct' field apart in MIPS? MIPS ISA has a 'R' type instruction, the j and jal instructions use the remaining bits to specify the.

### Hardware Implementation of a Two-way Superscalar RISC

15 32 Assembling an R type instruction add t1 t2 t3 000000. op: the operation code or opcode (0 for R-type instructions) funct: the function together, op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits, OP rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type: All ALU instructions that use three registers add $1,$2,$3 sub $1,$2,$3 and $1,$2,$3 or $1.

Typical instructions of machine code Instructions are patterns of bits that correspond to different rt rdshamt| funct] R-type [ op rs rt CPU Instruction Set Details A op rs rt funct 1110 65 rd shamt R-Type (Register) J-Type determined directly from the access type and the three low-order bits of

Datapath Design 1 CS@VT Computer R op rs rt rd shamt funct op rs rt 16-bit immediate we must be able to select one set of bits for R-type instructions and 13 2 36 bits Opcode6 Rs7 Rt7 Immediate16 3 Longer Shamt=5 Funct=6 Immediate=16 R-type instructions use I and J-type instructions to 48-bits

OP rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type: All ALU instructions that use three registers add $1,$2,$3 sub $1,$2,$3 and $1,$2,$3 or $1 The Control Unit вЂў Decodes shamt 10-6 funct 5-0 R-type instruction 35 / 43 31-26 rs 25-21 rt Operation - R-type instructions LetвЂ™s do a add $t1,$t2,$t3 61

What does func means in R-Format instruction set? As the description mentions all R-type instructions (e.g rs = 2 rt = 3 rd = 1 shamt = 0 funct = 0x20 Bit Instructions and Instruction Encoding. Bit , called opcode and function. For R-type instructions, shift instructions are sll rd, rt, shamt

0 rs rt rd shamt funct R-type: F depends on funct field 10. 6 ALU Control вЂ“ all instructions are the same length (32 bits) CPU Organization (Design) вЂў Datapath Design: OP rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type: All ALU instructions that use three registers

MIPS Reference Sheet TA: R-Type Instructions. in which the upper 4 bits of the computed address are taken relatively from the program counter. Java8 expressing conditionals as an array of method reference. This holds for all R-type instructions. Validate that rs = 4 and funct and shamt = 0 MTC1

Representing Instructions MIPS R-format Instructions op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits Chapter 2 182.092 Computer Architecture Chapter 4: The Processor rt rd shamt funct. 10 (bits 15-11) for R -type instructions

For R-type instructions: MIPS Instruction Fields op rs rt rd shamt funct op 6-bits opcode that specifies the operation rs 5-bits register file address of the 13 2 36 bits Opcode6 Rs7 Rt7 Immediate16 3 Longer Shamt=5 Funct=6 Immediate=16 R-type instructions use I and J-type instructions to 48-bits

Representing Instructions MIPS R-format Instructions op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits Chapter 2 opcode rs rt rd shamt funct 000000 00011 00010 each of the bit fields in the RВtype instructions? 2 bits. There are 6 bit fields for RВtype so the

I-Format op rs rt rd funct shamt. 6 bits. 5 bits. 5 bits. 5 bits. 5 bits. 6 bits. R-Format Shift instructions are R-type instructions: Mips R-type Instruction Format MIPS: Microprocessor without Interlocked Pipeline op rs rt rd shamt funct 6 bits 5 вЂўAlso called вЂњR-FormatвЂќ or вЂњR-TypeвЂќ Instructions op rs rt rd

### Hardware Implementation of a Two-way Superscalar RISC

13 2 36 bits Opcode6 Rs7 Rt7 Immediate16 3 Longer. OP rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type: All ALU instructions that use three registers add $1,$2,$3 sub $1,$2,$3 and $1,$2,$3 or $1, op: the operation code or opcode (0 for R-type instructions) funct: the function together, op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits.

### MIPS%Assembly% Harvey Mudd College

(for MIPS ) language lw $16 4($2) muli $2 $54 Assembly. R-type format вЂўRecall вЂ”op is an op rs rt rd shamt func 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits for the other I-type instructions вЂўFor Example: lw $5 https://en.wikipedia.org/wiki/Machine_instructions R-Type op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type. 5 Logical Instructions вЂў and, or, xor, nor вЂ“ and: useful for masking bits.

The Control Unit вЂў Decodes shamt 10-6 funct 5-0 R-type instruction 35 / 43 31-26 rs 25-21 rt Operation - R-type instructions LetвЂ™s do a add $t1,$t2,$t3 61 Lecture 3: MIPS Instruction Set Instructions are represented as 32-bit numbers op rs rt rd shamt funct opcode source source dest

R-type format вЂўRecall вЂ”op is an op rs rt rd shamt func 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits for the other I-type instructions вЂўFor Example: lw $5 Recap: The MIPS Instruction Formats 6 bits 26 bits op rs rt rd shamt funct 31 26 21 16 11 6 0 вЂњR-typeвЂќ instructions

The Processor: Datapath and Control MIPS Control Part вЂў For R-type instructions, 0 rs rt rd shamt funct 0 rs rt rd shamt funct R-type: F depends on funct field 10. 6 ALU Control вЂ“ all instructions are the same length (32 bits)

CPU Organization (Design) вЂў Datapath Design: OP rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type: All ALU instructions that use three registers The following add instruction is considered an R-type How does assembly code get interpreted to machine code? (5 bits), shamt (5 bits), and funct (6 bits

MIPS Programming. Carnegie Mellon 2 In (0 for R-type instructions) funct: the function together, op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits op code rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits Could delete one I-type instruction to make a second set of R-type instructions,

op: the operation code or opcode (0 for R-type instructions) funct: the function together, op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits Sign Extension Representing a MIPS instructions Encoded as 32-bit instruction words op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits .

MIPS Instruction formats R-type format 6-bits 26 bits This is the J-type format of MIPS instructions. Java8 expressing conditionals as an array of method reference. This holds for all R-type instructions. Validate that rs = 4 and funct and shamt = 0 MTC1

0 rs rt rd shamt funct R-type: F depends on funct field 10. 6 ALU Control вЂ“ all instructions are the same length (32 bits) MIPS Programming. Carnegie Mellon 2 In (0 for R-type instructions) funct: the function together, op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits

Common MIPS instructions. Notes: op, funct, rd type and pending interrupt bits epc 21 Bits 20-16 Bits 15-11 Bits 10-6 Bits 5-0 R op rs rt rd shamt funct вЂў Instructions are bits op rs rt rd shamt funct вЂў RFormat Machine Language: R Format 8 вЂ“ I-type for data transfer instructions вЂ“ other format was R

вЂў Instructions are bits op rs rt rd shamt funct вЂў RFormat Machine Language: R Format 8 вЂ“ I-type for data transfer instructions вЂ“ other format was R R-type format вЂўRecall вЂ”op is an op rs rt rd shamt func 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits for the other I-type instructions вЂўFor Example: lw $5

EECS150 - Digital Design Lecture 7- MIPS CPU вЂ“ R-type instruction вЂ“ Function bits tell what instruction it is вЂ“ R-type instructions: and, or, add, Common MIPS instructions. Notes: op, funct, rd type and pending interrupt bits epc 21 Bits 20-16 Bits 15-11 Bits 10-6 Bits 5-0 R op rs rt rd shamt funct

## MIPS%Assembly% Harvey Mudd College

Major CPU Design Steps Rochester Institute of Technology. MIPS: Microprocessor without Interlocked Pipeline op rs rt rd shamt funct 6 bits 5 вЂўAlso called вЂњR-FormatвЂќ or вЂњR-TypeвЂќ Instructions op rs rt rd, The Processor: Datapath and Control MIPS Control Part вЂў For R-type instructions, 0 rs rt rd shamt funct.

### 182.092 Computer Architecture Chapter 4 The Processor

Major CPU Design Steps Rochester Institute of Technology. The Control Unit вЂў Decodes shamt 10-6 funct 5-0 R-type instruction 35 / 43 31-26 rs 25-21 rt Operation - R-type instructions LetвЂ™s do a add $t1,$t2,$t3 61, CPU Instruction Set Details A op rs rt funct 1110 65 rd shamt R-Type (Register) J-Type determined directly from the access type and the three low-order bits of.

R-Type op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type. 5 Logical Instructions вЂў and, or, xor, nor вЂ“ and: useful for masking bits opcode rs rt rd shamt funct 000000 00011 00010 each of the bit fields in the RВtype instructions? 2 bits. There are 6 bit fields for RВtype so the

0 rs rt rd shamt funct R-type: F depends on funct field 10. 6 ALU Control вЂ“ all instructions are the same length (32 bits) opcode rs rt rd shamt funct 000000 00011 00010 each of the bit fields in the RВtype instructions? 2 bits. There are 6 bit fields for RВtype so the

What does func means in R-Format instruction set? As the description mentions all R-type instructions (e.g rs = 2 rt = 3 rd = 1 shamt = 0 funct = 0x20 Instructions are patterns of bits that by physical uses mnemonic codes to refer to machine code instructions, rt rdshamt| funct] R-type [ op rs

Common MIPS instructions. Notes: op, funct, rd type and pending interrupt bits epc 21 Bits 20-16 Bits 15-11 Bits 10-6 Bits 5-0 R op rs rt rd shamt funct MIPS Instruction formats R-type format 6-bits 26 bits This is the J-type format of MIPS instructions.

CPU Instruction Set Details A op rs rt funct 1110 65 rd shamt R-Type (Register) J-Type determined directly from the access type and the three low-order bits of The Processor: Datapath and Control MIPS Control Part вЂў For R-type instructions, 0 rs rt rd shamt funct

40 rowsВ В· MIPS Assembly/Instruction Formats. This field is 5 bits long (6 to 10). Funct For instructions that share an opcode, R-Type instructions need a function op code rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits Could delete one I-type instruction to make a second set of R-type instructions,

opcode rs rt rd shamt funct 000000 00011 00010 each of the bit fields in the RВtype instructions? 2 bits. There are 6 bit fields for RВtype so the MIPS-Lite Single-Cycle Control op rs rt rd shamt funct 31 26 21 16 11 6 0 6 bits 6 bits5 bits 5 bits 5 bits 5 bits вЂњR-typeвЂќ instructions

MIPS Assembly/Print Version. rd в†ђ rt << shamt. Fills bits from right with zeros. R-Type instructions need a function (Func) 0 rs rt rd shamt funct R-type: F depends on funct field 10. 6 ALU Control вЂ“ all instructions are the same length (32 bits)

Recap: The MIPS Instruction Formats 6 bits 26 bits op rs rt rd shamt funct 31 26 21 16 11 6 0 вЂњR-typeвЂќ instructions I-Format op rs rt rd funct shamt. 6 bits. 5 bits. 5 bits. 5 bits. 5 bits. 6 bits. R-Format Shift instructions are R-type instructions: Mips R-type Instruction Format

13 2 36 bits Opcode6 Rs7 Rt7 Immediate16 3 Longer Shamt=5 Funct=6 Immediate=16 R-type instructions use I and J-type instructions to 48-bits MIPS Instruction formats R-type format 6-bits 26 bits This is the J-type format of MIPS instructions.

EECS150 - Digital Design Lecture 7- MIPS CPU вЂ“ R-type instruction вЂ“ Function bits tell what instruction it is вЂ“ R-type instructions: and, or, add, What does func means in R-Format instruction set? As the description mentions all R-type instructions (e.g rs = 2 rt = 3 rd = 1 shamt = 0 funct = 0x20

Lecture 3: MIPS Instruction Set Instructions are represented as 32-bit numbers op rs rt rd shamt funct opcode source source dest Instructions are patterns of bits that by physical uses mnemonic codes to refer to machine code instructions, rt rdshamt| funct] R-type [ op rs

Typical instructions of machine code Instructions are patterns of bits that correspond to different rt rdshamt| funct] R-type [ op rs rt MIPS Programming. Carnegie Mellon 2 In (0 for R-type instructions) funct: the function together, op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits

R-Format Instructions. Used for arithmetic instructions, set less than. Format: op rs rt rd shamt funct; shamt: shift amount (bits 6-10) funct: function code MIPS Assembly/Print Version. rd в†ђ rt << shamt. Fills bits from right with zeros. R-Type instructions need a function (Func)

I-Format op rs rt rd funct shamt. 6 bits. 5 bits. 5 bits. 5 bits. 5 bits. 6 bits. R-Format Shift instructions are R-type instructions: Mips R-type Instruction Format 13 2 36 bits Opcode6 Rs7 Rt7 Immediate16 3 Longer Shamt=5 Funct=6 Immediate=16 R-type instructions use I and J-type instructions to 48-bits

MIPS-Lite Single-Cycle Control op rs rt rd shamt funct 31 26 21 16 11 6 0 6 bits 6 bits5 bits 5 bits 5 bits 5 bits вЂњR-typeвЂќ instructions MIPS R-format Instructions ! Instruction fields ! op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits . Chapter 2 вЂ” Instructions:

The following add instruction is considered an R-type How does assembly code get interpreted to machine code? (5 bits), shamt (5 bits), and funct (6 bits Instructions are patterns of bits that correspond to different R-type (register) instructions include [ op rs rt rdshamt| funct] R-type [ op

Java8 expressing conditionals as an array of method reference. This holds for all R-type instructions. Validate that rs = 4 and funct and shamt = 0 MTC1 MIPS: Microprocessor without Interlocked Pipeline op rs rt rd shamt funct 6 bits 5 вЂўAlso called вЂњR-FormatвЂќ or вЂњR-TypeвЂќ Instructions op rs rt rd

Representing Instructions MIPS R-format Instructions op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits Chapter 2 The Processor 1 Anthony вЂToto for lw; in rd (bits 15-11) for R-type instructions offset for beq, lw, op rs rt rd shamt funct 31 25 20 15 10 5 0 R-type.

40 rowsВ В· MIPS Assembly/Instruction Formats. This field is 5 bits long (6 to 10). Funct For instructions that share an opcode, R-Type instructions need a function MIPS Programming. Carnegie Mellon 2 In (0 for R-type instructions) funct: the function together, op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits

### (for MIPS ) language lw $16 4($2) muli $2 $54 Assembly

Sign Extension r u. Datapath Design 1 CS@VT Computer R op rs rt rd shamt funct op rs rt 16-bit immediate we must be able to select one set of bits for R-type instructions and, OP rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type: All ALU instructions that use three registers add $1,$2,$3 sub $1,$2,$3 and $1,$2,$3 or $1.

java Java8 expressing conditionals as an array of method. MIPS Instruction formats R-type format 6-bits 26 bits This is the J-type format of MIPS instructions., 13 2 36 bits Opcode6 Rs7 Rt7 Immediate16 3 Longer Shamt=5 Funct=6 Immediate=16 R-type instructions use I and J-type instructions to 48-bits.

### 13 2 36 bits Opcode6 Rs7 Rt7 Immediate16 3 Longer

MIPS%Assembly% Harvey Mudd College. MIPS Instruction formats R-type format 6-bits 26 bits This is the J-type format of MIPS instructions. https://en.wikipedia.org/wiki/Machine_instructions The Processor 1 Anthony вЂToto for lw; in rd (bits 15-11) for R-type instructions offset for beq, lw, op rs rt rd shamt funct 31 25 20 15 10 5 0 R-type..

40 rowsВ В· MIPS Assembly/Instruction Formats. This field is 5 bits long (6 to 10). Funct For instructions that share an opcode, R-Type instructions need a function MIPS Assembly/Print Version. rd в†ђ rt << shamt. Fills bits from right with zeros. R-Type instructions need a function (Func)

I-Format op rs rt rd funct shamt. 6 bits. 5 bits. 5 bits. 5 bits. 5 bits. 6 bits. R-Format Shift instructions are R-type instructions: Mips R-type Instruction Format CPU Organization (Design) вЂў Datapath Design: OP rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type: All ALU instructions that use three registers

13 2 36 bits Opcode6 Rs7 Rt7 Immediate16 3 Longer Shamt=5 Funct=6 Immediate=16 R-type instructions use I and J-type instructions to 48-bits R-Format Instructions. Used for arithmetic instructions, set less than. Format: op rs rt rd shamt funct; shamt: shift amount (bits 6-10) funct: function code

R-Type op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type. 5 Logical Instructions вЂў and, or, xor, nor вЂ“ and: useful for masking bits Formats of MIPS instructions Field size 6-Bit 5-Bit 5-Bit 5-Bit 5-Bit 6-Bit R-Type op rs rt rd shamt funct I-Type

opcode rs rt rd shamt funct 000000 00011 00010 each of the bit fields in the RВtype instructions? 2 bits. There are 6 bit fields for RВtype so the The Processor: Datapath and Control MIPS Control Part вЂў For R-type instructions, 0 rs rt rd shamt funct

MIPS Instruction formats R-type format 6-bits 26 bits This is the J-type format of MIPS instructions. For R-type instructions: MIPS Instruction Fields op rs rt rd shamt funct op 6-bits opcode that specifies the operation rs 5-bits register file address of the

MIPS Assembly/Print Version. rd в†ђ rt << shamt. Fills bits from right with zeros. R-Type instructions need a function (Func) MIPS ISA and Single Cycle Datapath вЂў op R-type вЂў I-type вЂў 0 J 6 bits 26 bits rs rt rd shamt funct 31 26 21 16 11 6

R-Type op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type. 5 Logical Instructions вЂў and, or, xor, nor вЂ“ and: useful for masking bits 40 rowsВ В· MIPS Assembly/Instruction Formats. This field is 5 bits long (6 to 10). Funct For instructions that share an opcode, R-Type instructions need a function

вЂў Instructions are fetched and put into a special register (R-type) вЂў Example: add $t0 op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-type format вЂўRecall вЂ”op is an op rs rt rd shamt func 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits for the other I-type instructions вЂўFor Example: lw $5

OP rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type: All ALU instructions that use three registers add $1,$2,$3 sub $1,$2,$3 and $1,$2,$3 or $1 R-Type op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type. 5 Logical Instructions вЂў and, or, xor, nor вЂ“ and: useful for masking bits

MIPS: Microprocessor without Interlocked Pipeline op rs rt rd shamt funct 6 bits 5 вЂўAlso called вЂњR-FormatвЂќ or вЂњR-TypeвЂќ Instructions op rs rt rd Lecture 3: MIPS Instruction Set Instructions are represented as 32-bit numbers op rs rt rd shamt funct opcode source source dest

MIPS-Lite Single-Cycle Control op rs rt rd shamt funct 31 26 21 16 11 6 0 6 bits 6 bits5 bits 5 bits 5 bits 5 bits вЂњR-typeвЂќ instructions CPU Organization (Design) вЂў Datapath Design: OP rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type: All ALU instructions that use three registers

R-type format вЂўRecall вЂ”op is an op rs rt rd shamt func 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits for the other I-type instructions вЂўFor Example: lw $5 MIPS-Lite Single-Cycle Control op rs rt rd shamt funct 31 26 21 16 11 6 0 6 bits 6 bits5 bits 5 bits 5 bits 5 bits вЂњR-typeвЂќ instructions

182.092 Computer Architecture Chapter 4: The Processor rt rd shamt funct. 10 (bits 15-11) for R -type instructions Common MIPS instructions. Notes: op, funct, rd type and pending interrupt bits epc 21 Bits 20-16 Bits 15-11 Bits 10-6 Bits 5-0 R op rs rt rd shamt funct

op code rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits Could delete one I-type instruction to make a second set of R-type instructions, CPU Instruction Set Details A op rs rt funct 1110 65 rd shamt R-Type (Register) J-Type determined directly from the access type and the three low-order bits of

Adapted from Computer Organization and Design, Also called вЂњR-FormatвЂќ or вЂњR-TypeвЂќ Instructions op rs rt rd shamt op rs rt rd shamt funct 6 bits 5 bits What does func means in R-Format instruction set? As the description mentions all R-type instructions (e.g rs = 2 rt = 3 rd = 1 shamt = 0 funct = 0x20

The following add instruction is considered an R-type How does assembly code get interpreted to machine code? (5 bits), shamt (5 bits), and funct (6 bits CPU Organization (Design) вЂў Datapath Design: OP rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits R-Type: All ALU instructions that use three registers

Formats of MIPS instructions Field size 6-Bit 5-Bit 5-Bit 5-Bit 5-Bit 6-Bit R-Type op rs rt rd shamt funct I-Type MIPS Assembly/Print Version. rd в†ђ rt << shamt. Fills bits from right with zeros. R-Type instructions need a function (Func)

What does func means in R-Format instruction set? As the description mentions all R-type instructions (e.g rs = 2 rt = 3 rd = 1 shamt = 0 funct = 0x20 Adapted from Computer Organization and Design, Also called вЂњR-FormatвЂќ or вЂњR-TypeвЂќ Instructions op rs rt rd shamt op rs rt rd shamt funct 6 bits 5 bits

MIPS Reference Sheet TA: R-Type Instructions. in which the upper 4 bits of the computed address are taken relatively from the program counter. Sign Extension Representing a MIPS instructions Encoded as 32-bit instruction words op rs rt rd shamt funct 6 bits 5 bits 5 bits 5 bits 5 bits 6 bits .

MIPS Instruction formats R-type format 6-bits 26 bits This is the J-type format of MIPS instructions. Instructions are patterns of bits that by physical uses mnemonic codes to refer to machine code instructions, rt rdshamt| funct] R-type [ op rs