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Mips ref exam - this is the mips reference sheet
Introduction To Computer Science (FIT1008)
Monash University
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MIPS reference sheet for FIT1008 and FIT
Semester 2, 2019
Table 1: System calls Call code ($v0)
Service Arguments Returns Notes
1 Print integer $a0= value to print - value is signed 4 Print string $a0= address of string to print - string must be termi- nated with’\0’ 5 Input integer - $v0= entered integer value is signed 8 Input string $a0 = address at which the string will be stored $a1 = maximum number of characters in the string
- returns if$a1-1char- acters or Enter typed, the string is termi- nated with’\0’ 9 Allocate memory $a0= number of bytes $v0= address of first byte - 10 Exit - - ends simulation
Table 2: General-purpose registers Number Name Purpose R00 $zero provides constant zero R01 $at reserved for assembler R02, R03 $v0, $v1 system call code, return value R04–R07 $a0--$a3 system call and function arguments R08–R15 $t0--$t7 temporary storage (caller-saved) R16–R23 $s0--$s7 temporary storage (callee-saved) R24, R25 $t8, $t9 temporary storage (caller-saved) R28 $gp pointer to global area R29 $sp stack pointer R30 $fp frame pointer R31 $ra return address
Table 3: Assembler directives .data assemble into data segment .text assemble into text (code) segment .word w1[, w2, ...] allocate word(s) with initial value(s) .space n allocate n bytes of uninitialized, unaligned space .ascii ”string” allocate ASCII string, do not terminate .asciiz ”string” allocate ASCII string, terminate with’\0’
Table 4: Function calling convention
On function call:
Caller: Callee: saves temporary registers on stack saves value of$raon stack passes arguments on stack saves value of$fpon stack calls function usingjal fnlabel copies$spto$fp allocates local variables on stack
On function return:
Callee: Caller: sets$v0to return value clears arguments off stack clears local variables off stack restores temporary registers off stack restores saved$fpoff stack uses return value in$v restores saved$raoff stack returns to caller withjr $ra
Table 5: A partial instruction set is provided below. The followingconventions apply. Instruction Formatcolumn Rsrc, Rsrc1, Rsrc2: register source operand(s) - must be the name of a register Rdest: register destination - must be the name of a register Addr: address in the formoffset(Rsrc), that is, absolute address =Rsrc + offset label: label of an instruction **: pseudoinstruction Immediate Formcolumn Associated instruction whereRsrc2is an immediate. Symbol - appears if there is no immediate form. Unsigned or overflowcolumn Associated unsigned (or overflow) instruction for the values ofRsrc1andRsrc2. Symbol - if no such form.
Table 6: Allowed MIPS instruction (and pseudoinstruction) set Instruction format Meaning Operation Immediate Unsigned or Overflow add Rdest, Rsrc1, Rsrc2 Add Rdest = Rsrc1 + Rsrc2 addi addu (no overflow trap) sub Rdest, Rsrc1, Rsrc2 Subtract Rdest = Rsrc1 - Rsrc2 - subu (no overflow trap) mult Rsrc1, Rsrc2 Multiply Hi:Lo = Rsrc1 * Rsrc2 - mulu div Rsrc1, Rsrc2 Divide Lo = Rsrc1/Rsrc2; Hi = Rsrc1 % Rsrc
- divu
and Rdest, Rsrc1, Rsrc2 Bitwise AND Rdest = Rsrc1 & Rsrc2 andi - or Rdest, Rsrc1, Rsrc2 Bitwise OR Rdest = Rsrc1|Rsrc2 ori - xor Rdest, Rsrc1, Rsrc2 Bitwise XOR Rdest = Rsrc1∧Rsrc2 xori - nor Rdest, Rsrc1, Rsrc2 Bitwise NOR Rdest =∼(Rsrc1|Rsrc2) - - sllv Rdest, Rsrc1, Rsrc2 Shift Left Logical Rdest = Rsrc1<<Rsrc2 sll - srlv Rdest, Rsrc1, Rsrc2 Shift Right Logical Rdest = Rsrc1>>Rsrc (MSB=0)
srl -
srav Rdest, Rsrc1, Rsrc2 Shift Right Arithmet. Rdest = Rsrc1>>Rsrc (MSB preserved)
sra -
mfhi Rdest Move from Hi Rdest = Hi - - mflo Rdest Move from Lo Rdest = Lo - - lw Rdest, Addr Load word Rdest = mem32[Addr] - - sw Rsrc, Addr Store word mem32[Addr] = Rsrc - - la Rdest, Addr(or label) ** Load Address (for printing strings)
Rdest=Addr (or Rdest=label)
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beq Rsrc1, Rsrc2, label Branch if equal if (Rsrc1 == Rsrc2) PC = label
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bne Rsrc1, Rsrc2, label Branch if not equal if (Rsrc1 != Rsrc2) PC = label
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slt Rdest, Rsrc1, Rsrc2 Set if less than if (Rsrc1<Rsrc2) Rdest = 1 else Rdest = 0
slti sltu , sltiu
j label Jump PC = label - - jal label Jump and link $ra = PC + 4; PC = label
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jr Rsrc Jump register PC = Rsrc - - jalr Rsrc Jump and link register $ra = PC + 4; PC = Rsrc
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syscall system call depends on the value of $v
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Mips ref exam - this is the mips reference sheet
Course: Introduction To Computer Science (FIT1008)
University: Monash University
