$29
Project #5 Decoder Solution
Note that this extra project is optional. If you decide not to work on this project, your midterm score will remain the same. If you decide to work on this project, 4 or 7 points will be added to your midterm as follows:
Part I (4 points) Part II (3 points)
Note that you midterm score is maxed at 55 points.
Part I: What is that instruction (4 Points)
What you need to do is to implement a program named mc2instr.asm that decode a 32-bit machine code (in hexadecimal) back to instruction. Simply put, your program will ask user to enter a 32-bit machine code in a form of an 8-digit hexadecimal number and prints out the instruction associated with the given machine code as shown below:
Please enter a machine code (hexadecimal): 00028020 add
Please enter a machine code (hexadecimal): 00108e82 srl
Please enter a machine code (hexadecimal): 2008ffff addi
Please enter a machine code (hexadecimal): 3211003f andi
Please enter a machine code (hexadecimal): 11020027 beq
Please enter a machine code (hexadecimal): 08100086 j
Please enter a machine code (hexadecimal): 0c1000bd jal
Please enter a machine code (hexadecimal): afbf0000 sw
Please enter a machine code (hexadecimal): 03e00008 jr
Once your program prints the name of the instruction, simply asks a user again. For simplicity, you do not need to check whether a user enter a valid 8-digit hexadecimal string and we will only test with instructions listed in Table 1.
1
Instruction
op (Hex)
op (Bin)
funct (Hex)
funct (Bin)
add
00hex
000000
20hex
100000
addi
08hex
001000
N/A
N/A
and
00hex
000000
24hex
100100
andi
0Chex
001100
N/A
N/A
sub
00hex
000000
22hex
100010
or
00hex
000000
25hex
100101
ori
0Dhex
001101
N/A
N/A
nor
00hex
000000
27hex
100111
slt
00hex
000000
2Ahex
101010
slti
0Ahex
001010
N/A
N/A
sll
00hex
000000
00hex
000000
srl
00hex
000000
02hex
000010
beq
04hex
000100
N/A
N/A
bne
05hex
000101
N/A
N/A
j
02hex
000010
N/A
N/A
jal
03hex
000011
N/A
N/A
jr
00hex
000000
08hex
001000
lw
23hex
100011
N/A
N/A
sw
2Bhex
101011
N/A
N/A
lh
21hex
100001
N/A
N/A
sh
29hex
101001
N/A
N/A
lb
20hex
100000
N/A
N/A
sb
28hex
101000
N/A
N/A
Table 1: Instructions and Control Values
Note that you program needs to print only the instruction mnemonic. It does not have to print the complete instruction in this part.
Part II: Operands (3 Points)
This part is an extension to the Part I. Simply make your program prints a complete instruction associated with the given 8-digit hexadecimal machine code as shown below:
Please enter a machine code (hexadecimal): 00028020
add $s0, $zero, $v0
Please enter a machine code (hexadecimal): 00108e82
srl $s1, $s0, 26
Please enter a machine code (hexadecimal): 2008ffff
addi $t0, $zero, -1
Please enter a machine code (hexadecimal): 3211003f
andi $s1, $s0, 63
Please enter a machine code (hexadecimal): 11020027
beq $t0, $v0, Label
Please enter a machine code (hexadecimal): 08100086
j Label
2
Please enter a machine code (hexadecimal): 0c1000bd jal Label
Please enter a machine code (hexadecimal): afbf0000 sw $ra, 0($sp)
Please enter a machine code (hexadecimal): 03e00008 jr $ra
Note that for instructions that need a label (beq, bne, j, and jal), simply print the string Label as shown above. All immediate values should be printed in decimal (using system call 1) for simplicity. The MIPS Reference Data can be found on the next page.
Submission
The due date of this project is stated on the CourseWeb. Late submissions will not be accepted. You should submit the le mc2instr.asm via CourseWeb. Again, we will only test your program with valid hexadecimal and instructions listed above. No need to perform error checking.
3
MIPS REFERENCE DATA CARD (“GREEN CARD”) 1. Pull along perforation to separate card 2. Fold bottom side (columns 3 and 4) together
1
ARITHMETIC CORE INSTRUCTION SET
2
OPCODE
M I P S REFERENCE DATA
/ FMT /FT
NAME, MNEMONIC
FOR-
OPERATION
/ FUNCT
MAT
(Hex)
Branch On FP True
bc1t
FI
if(FPcond)PC=PC+4+BranchAddr (4)
11/8/1/--
CORE INSTRUCTION SET
OPCODE
Branch On FP False bc1f
FI
if(!FPcond)PC=PC+4+BranchAddr(4)
11/8/0/--
FOR-
/ FUNCT
Divide
R
Lo=R[rs]/R[rt]; Hi=R[rs]%R[rt]
0/--/--/1a
NAME, MNEMONICMAT
OPERATION (in Verilog)
(Hex)
div
Divide Unsigned
R
Lo=R[rs]/R[rt]; Hi=R[rs]%R[rt]
(6)
0/--/--/1b
Add
add
R R[rd] = R[rs] + R[rt]
(1)
0 / 20hex
divu
FP Add Single
add.s
FR
F[fd ]= F[fs] + F[ft]
11/10/--/0
Add Immediate
addi
I R[rt] = R[rs] + SignExtImm
(1,2)
8hex
FP Add
FR
{F[fd],F[fd+1]} = {F[fs],F[fs+1]} +
11/11/--/0
Add Imm. Unsigned
I R[rt] = R[rs] + SignExtImm
(2)
9hex
add.d
addiu
Double
{F[ft],F[ft+1]}
Add Unsigned
addu
R R[rd] = R[rs] + R[rt]
0 / 21hex
FP Compare Single
c.x.s*
FR
FPcond = (F[fs] op F[ft]) ? 1 : 0
11/10/--/y
And
and
R R[rd] = R[rs] & R[rt]
0 / 24hex
FP Compare
c.x.d*
FR
FPcond = ({F[fs],F[fs+1]} op
11/11/--/y
And Immediate
I R[rt] = R[rs] & ZeroExtImm
(3)
chex
Double
{F[ft],F[ft+1]}) ? 1 : 0
andi
* (x is eq, lt, or le) (op is ==, <, or <=) ( y is 32, 3c, or 3e)
Branch On Equal
beq
I
if(R[rs]==R[rt])
4hex
FP Divide Single
div.s
FR
F[fd] = F[fs] / F[ft]
11/10/--/3
PC=PC+4+BranchAddr
(4)
FP Divide
FR
{F[fd],F[fd+1]} = {F[fs],F[fs+1]} /
11/11/--/3
div.d
Branch On Not Equal bne
I
if(R[rs]!=R[rt])
5hex
Double
{F[ft],F[ft+1]}
FP Multiply Single
FR
F[fd] = F[fs] * F[ft]
11/10/--/2
PC=PC+4+BranchAddr
(4)
mul.s
FP Multiply
{F[fd],F[fd+1]} = {F[fs],F[fs+1]} *
Jump
j
J
PC=JumpAddr
(5)
2hex
mul.d
FR
11/11/--/2
Jump And Link
J
R[31]=PC+8;PC=JumpAddr
(5)
3hex
Double
{F[ft],F[ft+1]}
jal
FP Subtract Single
sub.s
FR
F[fd]=F[fs] - F[ft]
11/10/--/1
Jump Register
jr
R
PC=R[rs]
0 / 08hex
FP Subtract
sub.d
FR
{F[fd],F[fd+1]} = {F[fs],F[fs+1]} -
11/11/--/1
Load Byte Unsigned
I
R[rt]={24’b0,M[R[rs]
24hex
Double
{F[ft],F[ft+1]}
lbu
Load FP Single
I
F[rt]=M[R[rs]+SignExtImm]
(2)
31/--/--/--
+SignExtImm](7:0)}
(2)
lwc1
Load FP
F[rt]=M[R[rs]+SignExtImm];
(2)
Load Halfword
I
R[rt]={16’b0,M[R[rs]
25hex
ldc1
I
35/--/--/--
Unsigned
lhu
+SignExtImm](15:0)}
(2)
Double
F[rt+1]=M[R[rs]+SignExtImm+4]
Move From Hi
mfhi
R
R[rd] = Hi
0 /--/--/10
Load Linked
ll
I
R[rt] = M[R[rs]+SignExtImm]
(2,7)
30hex
Move From Lo
mflo
R
R[rd] = Lo
0 /--/--/12
Load Upper Imm.
I R[rt] = {imm, 16’b0}
fhex
lui
Move From Control mfc0
R
R[rd] = CR[rs]
10 /0/--/0
Load Word
lw
I
R[rt] = M[R[rs]+SignExtImm]
(2)
23hex
Multiply
mult
R
{Hi,Lo} = R[rs] *
R[rt]
0/--/--/18
Nor
nor
R R[rd] = ~ (R[rs] | R[rt])
0 / 27hex
Multiply Unsigned
multu
R
{Hi,Lo} = R[rs] *
R[rt]
(6)
0/--/--/19
Shift Right Arith.
sra
R
R[rd] = R[rt] shamt
0/--/--/3
Or
or
R R[rd] = R[rs] | R[rt]
0 / 25hex
Store FP Single
swc1
I
M[R[rs]+SignExtImm] = F[rt]
(2) 39/--/--/--
dhex
Or Immediate
ori
I R[rt] = R[rs] | ZeroExtImm
(3)
Store FP
sdc1
I
M[R[rs]+SignExtImm] = F[rt];
(2)
3d/--/--/--
Set Less Than
R R[rd] = (R[rs] < R[rt]) ? 1 : 0
0 / 2ahex
Double
M[R[rs]+SignExtImm+4] = F[rt+1]
slt
Set Less Than Imm.
slti
I R[rt] = (R[rs] < SignExtImm)? 1 : 0 (2)
ahex
FLOATING-POINT INSTRUCTION FORMATS
Set Less Than Imm.
sltiu
I
R[rt] = (R[rs] < SignExtImm)
bhex
FR
opcode
fmt
ft
fs
fd
funct
Unsigned
?1:0
(2,6)
31
26 25
21 20
16 15
11 10
6 5
0
Set Less Than Unsig. sltu
R R[rd] = (R[rs] < R[rt]) ? 1 : 0
(6)
0 / 2bhex
FI
opcode
fmt
ft
immediate
Shift Left Logical
sll
R R[rd] = R[rt] << shamt
0 / 00hex
31
26 25
21 20
16 15
0
Shift Right Logical
srl
R R[rd] = R[rt] shamt
0 / 02hex
PSEUDOINSTRUCTION SET
Store Byte
sb
I
M[R[rs]+SignExtImm](7:0) =
28hex
NAME
MNEMONIC
OPERATION
R[rt](7:0)
(2)
Branch Less Than
blt
if(R[rs]<R[rt]) PC = Label
Store Conditional
sc
I
M[R[rs]+SignExtImm] = R[rt];
38hex
Branch Greater Than
bgt
if(R[rs]R[rt]) PC = Label
R[rt] = (atomic) ? 1 : 0
(2,7)
Branch Less Than or Equal
ble
if(R[rs]<=R[rt]) PC = Label
M[R[rs]+SignExtImm](15:0) =
29hex
Branch Greater Than or Equal
bge
if(R[rs]=R[rt]) PC = Label
Store Halfword
sh
I
Load Immediate
li
R[rd] = immediate
R[rt](15:0)
(2)
Move
move
R[rd] = R[rs]
Store Word
sw
I
M[R[rs]+SignExtImm] = R[rt]
(2)
2bhex
REGISTER NAME, NUMBER, USE, CALL CONVENTION
Subtract
sub
R
R[rd] = R[rs] - R[rt]
(1)
0 / 22hex
NAME NUMBER
USE
PRESERVED ACROSS
Subtract Unsigned
R
R[rd] = R[rs] - R[rt]
0 / 23hex
subu
A CALL?
(1) May cause overflow exception
$zero
0
The Constant Value 0
N.A.
(2) SignExtImm = { 16{immediate[15]}, immediate }
$at
1
Assembler Temporary
No
(3) ZeroExtImm = { 16{1b’0}, immediate }
Values for Function Results
(4) BranchAddr = { 14{immediate[15]}, immediate, 2’b0 }
$v0-$v1
2-3
No
and Expression Evaluation
(5) JumpAddr = { PC+4[31:28], address, 2’b0 }
(6) Operands considered unsigned numbers (vs. 2’s comp.)
$a0-$a3
4-7
Arguments
No
(7) Atomic test&set pair; R[rt] = 1 if pair atomic, 0 if not atomic
$t0-$t7
8-15
Temporaries
No
BASIC INSTRUCTION FORMATS
$s0-$s7
16-23
Saved Temporaries
Yes
$t8-$t9
24-25
Temporaries
No
R
opcode
rs
rt
rd
shamt
funct
$k0-$k1
26-27
Reserved for OS Kernel
No
31
26 25
21 20
16 15
11 10
6 5
0
$gp
28
Global Pointer
Yes
I
opcode
rs
rt
immediate
$sp
29
Stack Pointer
Yes
31
26 25
21 20
16 15
0
$fp
30
Frame Pointer
Yes
J
opcode
address
$ra
31
Return Address
Yes
31
26 25
0
Copyright 2009 by Elsevier, Inc., All rights reserved. From Patterson and Hennessy, Computer Organization and Design, 4th ed.
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