# Lab2:RISC-V Toolchain
###### tags: `RISC-V` `2022 Computer Architecture`
###### contributed by <[YongDa Su](https://github.com/YongDaSu/2022ComputerArchitecture/tree/main/Lab02)>
## [environment setup](https://hackmd.io/@2gMSvG25RxKj2-N_rAY6zg/B1eNc_Ggco)
## Question Selection
### **Motivation**
In this Question, it use a for loop and a nest if loop, so I believe that this is a good one to practice how to optimize other peoples' program.
### **Question**
Three Consecutive Odds from [王漢祺](https://hackmd.io/BF459yoPRe2oLbZHiy22xw?view) ([leetcode 1550](https://leetcode.com/problems/three-consecutive-odds/))
### **Describe:**
Given an integer array `arr`, return `true` if there are three consecutive odd numbers in the array. Otherwise, return `false`.
### **example:**
### **Program flow chart**
### **C code**
I change the input test, and find out some mistake. In the c program part, I could not improve the code properly, so I looked into the assembly part, I found some memory fault.
In some cases of the array, the result was not correct.
Then I fixed part, not only the memory fault but also improve some performance(by reducing some redundant registers and code).
```c
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
bool threeConsecutiveOdds(int *arr, int arrSize)
{
int i;
int count = 0;
if (arrSize < 3)
return false;
for (i = 0; i < arrSize; i++)
{
if (*(arr + i) & 1)
{
if (++count == 3)
return true;
}
else
{
count = 0;
}
}
return false;
}
int main(int argc, char *argv[])
{
int test1[2] = {2, 6};
int test2[9] = {1, 2, 34, 3, 4, 5, 7, 23, 25};
int test3[6] = {1, 3, 4, 7, 9, 12};
bool answer1 = threeConsecutiveOdds(test1, sizeof(test1) / sizeof(test1[0]));
bool answer2 = threeConsecutiveOdds(test2, sizeof(test2) / sizeof(test2[0]));
bool answer3 = threeConsecutiveOdds(test3, sizeof(test3) / sizeof(test3[0]));
printf("The answer1 is %d\n", answer1);
printf("The answer2 is %d\n", answer2);
printf("The answer3 is %d\n", answer3);
return 0;
}
/*** terminal output
The answer1 is 0
The answer2 is 1
The answer3 is 0
--------------------------------
Process exited after 0.02739 seconds with return value 0
Press any key to continue . . .
***/
```
### **Assembly code(modify)**
```RISC-V
.data
arr1: .word 2, 6
arr2: .word 1, 2, 34, 3, 4, 5, 7, 23, 25
arr3: .word 1, 3, 4, 7, 9, 12
str0: .string "\nThe answer is false\n"
str1: .string "\nThe answer is true\n"
str2: .string " "
#the size of array is known in advanced.
arr1_size: .word 2
arr2_size: .word 9
arr3_size: .word 6
.text
# a0 : save the return value
# a1 : the base address of arr
# a2 : the size of arr
# t1 : count
# t2 : 3
# s0 : arr[i]
# s1 : the value of (*(arr + 1) & 1)
initialize:
la a1, arr1
lw a2, arr1_size
addi t1, x0, 0
addi t2, x0, 3
jal ra, print_array
la a1, arr1 #recover the addr of array1
lw a2, arr1_size #recover the array size of array1
jal ra, main #strat main program
la a1, arr2
lw a2, arr2_size
addi t1, x0, 0
addi t2, x0, 3
jal ra, print_array
la a1, arr2 #recover the addr of array1
lw a2, arr2_size #recover the array size of array1
jal ra, main #strat main program
la a1, arr3
lw a2, arr3_size
addi t1, x0, 0
addi t2, x0, 3
jal ra, print_array
la a1, arr3 #recover the addr of array1
lw a2, arr3_size #recover the array size of array1
jal ra, main #strat main program
li a7, 10
ecall
print_array: #print all array element
lw s0, 0(a1) #load element
addi a0, s0, 0 #a0 = s0
li a7, 1 #print string
ecall
la a0, str2 #print space
li a7, 4
ecall
addi a1, a1, 4 #next element
addi a2, a2, -1 #array size -1
bne a2, x0, print_array #if still have element, go print
ret
main:
blt a2, t2, False #if array size <3, go to False directly
for_loop:
addi a2, a2, -1 #array size -1
lw s0, 0(a1) #load element
addi a1, a1, 4 #next element
andi s1, s0, 1 #bitwise and 1, if an odd, s1 = 1
bne s1, x0, ADD_1 #branch to ADD1 if an odd
addi t1, x0, 0 #count = 0 if even
bne a2, x0, for_loop #if still have element, go to for_loop
j False #if no consecutive odds, j False
ADD_1:
addi t1, t1, 1 #count = count + 1
beq t1, t2, True #if count = 3, True
bne a2, x0, for_loop #if count != 3 but still have other elements in the array
j False
True:
la a0, str1
li a7, 4
ecall
ret
False:
la a0, str0
li a7, 4
ecall
ret
```
## **RV32emu**
### Process
:::info
1.Compile
:::
:::info
2.Size
:::
:::info
3.ELF header
:::
:::info
4.Assembly code
:::
### Size compare
O0
O1
O2
O3
Os
Ofast
### ELF compare
O0
O1
O2
O3
Os
Ofast
### **Observation**
:::info
O0->O1 : slightly change
Os : best optimization
O2 & O3 : almost the same
:::
### **Assembly code**
O0
```RISCV
00010184 <threeConsecutiveOdds>:
10184: fd010113 addi sp,sp,-48
10188: 02812623 sw s0,44(sp)
1018c: 03010413 addi s0,sp,48
10190: fca42e23 sw a0,-36(s0)
10194: fcb42c23 sw a1,-40(s0)
10198: fe042423 sw zero,-24(s0)
1019c: fd842703 lw a4,-40(s0)
101a0: 00200793 li a5,2
101a4: 00e7c663 blt a5,a4,101b0 <threeConsecutiveOdds+0x2c>
101a8: 00000793 li a5,0
101ac: 0680006f j 10214 <threeConsecutiveOdds+0x90>
101b0: fe042623 sw zero,-20(s0)
101b4: 0500006f j 10204 <threeConsecutiveOdds+0x80>
101b8: fec42783 lw a5,-20(s0)
101bc: 00279793 slli a5,a5,0x2
101c0: fdc42703 lw a4,-36(s0)
101c4: 00f707b3 add a5,a4,a5
101c8: 0007a783 lw a5,0(a5)
101cc: 0017f793 andi a5,a5,1
101d0: 02078263 beqz a5,101f4 <threeConsecutiveOdds+0x70>
101d4: fe842783 lw a5,-24(s0)
101d8: 00178793 addi a5,a5,1
101dc: fef42423 sw a5,-24(s0)
101e0: fe842703 lw a4,-24(s0)
101e4: 00300793 li a5,3
101e8: 00f71863 bne a4,a5,101f8 <threeConsecutiveOdds+0x74>
101ec: 00100793 li a5,1
101f0: 0240006f j 10214 <threeConsecutiveOdds+0x90>
101f4: fe042423 sw zero,-24(s0)
101f8: fec42783 lw a5,-20(s0)
101fc: 00178793 addi a5,a5,1
10200: fef42623 sw a5,-20(s0)
10204: fec42703 lw a4,-20(s0)
10208: fd842783 lw a5,-40(s0)
1020c: faf746e3 blt a4,a5,101b8 <threeConsecutiveOdds+0x34>
10210: 00000793 li a5,0
10214: 00078513 mv a0,a5
10218: 02c12403 lw s0,44(sp)
1021c: 03010113 addi sp,sp,48
10220: 00008067 ret
00010224 <main>:
10224: f9010113 addi sp,sp,-112
10228: 06112623 sw ra,108(sp)
1022c: 06812423 sw s0,104(sp)
10230: 07010413 addi s0,sp,112
10234: f8a42e23 sw a0,-100(s0)
10238: f8b42c23 sw a1,-104(s0)
1023c: 00200793 li a5,2
10240: fef42223 sw a5,-28(s0)
10244: 00600793 li a5,6
10248: fef42423 sw a5,-24(s0)
1024c: 000227b7 lui a5,0x22
10250: 81478793 addi a5,a5,-2028 # 21814 <__clzsi2+0xc8>
10254: 0007a303 lw t1,0(a5)
10258: 0047a883 lw a7,4(a5)
1025c: 0087a803 lw a6,8(a5)
10260: 00c7a503 lw a0,12(a5)
10264: 0107a583 lw a1,16(a5)
10268: 0147a603 lw a2,20(a5)
1026c: 0187a683 lw a3,24(a5)
10270: 01c7a703 lw a4,28(a5)
10274: 0207a783 lw a5,32(a5)
10278: fc642023 sw t1,-64(s0)
1027c: fd142223 sw a7,-60(s0)
10280: fd042423 sw a6,-56(s0)
10284: fca42623 sw a0,-52(s0)
10288: fcb42823 sw a1,-48(s0)
1028c: fcc42a23 sw a2,-44(s0)
10290: fcd42c23 sw a3,-40(s0)
10294: fce42e23 sw a4,-36(s0)
10298: fef42023 sw a5,-32(s0)
1029c: 000227b7 lui a5,0x22
102a0: 83878793 addi a5,a5,-1992 # 21838 <__clzsi2+0xec>
102a4: 0007a503 lw a0,0(a5)
102a8: 0047a583 lw a1,4(a5)
102ac: 0087a603 lw a2,8(a5)
102b0: 00c7a683 lw a3,12(a5)
102b4: 0107a703 lw a4,16(a5)
102b8: 0147a783 lw a5,20(a5)
102bc: faa42423 sw a0,-88(s0)
102c0: fab42623 sw a1,-84(s0)
102c4: fac42823 sw a2,-80(s0)
102c8: fad42a23 sw a3,-76(s0)
102cc: fae42c23 sw a4,-72(s0)
102d0: faf42e23 sw a5,-68(s0)
102d4: fe440793 addi a5,s0,-28
102d8: 00200593 li a1,2
102dc: 00078513 mv a0,a5
102e0: ea5ff0ef jal ra,10184 <threeConsecutiveOdds>
102e4: 00050793 mv a5,a0
102e8: fef407a3 sb a5,-17(s0)
102ec: fc040793 addi a5,s0,-64
102f0: 00900593 li a1,9
102f4: 00078513 mv a0,a5
102f8: e8dff0ef jal ra,10184 <threeConsecutiveOdds>
102fc: 00050793 mv a5,a0
10300: fef40723 sb a5,-18(s0)
10304: fa840793 addi a5,s0,-88
10308: 00600593 li a1,6
1030c: 00078513 mv a0,a5
10310: e75ff0ef jal ra,10184 <threeConsecutiveOdds>
10314: 00050793 mv a5,a0
10318: fef406a3 sb a5,-19(s0)
1031c: fef44783 lbu a5,-17(s0)
10320: 00078593 mv a1,a5
10324: 000217b7 lui a5,0x21
10328: 7d878513 addi a0,a5,2008 # 217d8 <__clzsi2+0x8c>
1032c: 264000ef jal ra,10590 <printf>
10330: fee44783 lbu a5,-18(s0)
10334: 00078593 mv a1,a5
10338: 000217b7 lui a5,0x21
1033c: 7ec78513 addi a0,a5,2028 # 217ec <__clzsi2+0xa0>
10340: 250000ef jal ra,10590 <printf>
10344: fed44783 lbu a5,-19(s0)
10348: 00078593 mv a1,a5
1034c: 000227b7 lui a5,0x22
10350: 80078513 addi a0,a5,-2048 # 21800 <__clzsi2+0xb4>
10354: 23c000ef jal ra,10590 <printf>
10358: 00000793 li a5,0
1035c: 00078513 mv a0,a5
10360: 06c12083 lw ra,108(sp)
10364: 06812403 lw s0,104(sp)
10368: 07010113 addi sp,sp,112
1036c: 00008067 ret
```
O1
```RISCV
00010184 <threeConsecutiveOdds>:
10184: 00200793 li a5,2
10188: 04b7d463 bge a5,a1,101d0 <threeConsecutiveOdds+0x4c>
1018c: 00000693 li a3,0
10190: 00000713 li a4,0
10194: 00300613 li a2,3
10198: 0140006f j 101ac <threeConsecutiveOdds+0x28>
1019c: 00078693 mv a3,a5
101a0: 00170713 addi a4,a4,1
101a4: 00450513 addi a0,a0,4
101a8: 02e58063 beq a1,a4,101c8 <threeConsecutiveOdds+0x44>
101ac: 00052783 lw a5,0(a0)
101b0: 0017f793 andi a5,a5,1
101b4: fe0784e3 beqz a5,1019c <threeConsecutiveOdds+0x18>
101b8: 00168693 addi a3,a3,1
101bc: fec692e3 bne a3,a2,101a0 <threeConsecutiveOdds+0x1c>
101c0: 00100513 li a0,1
101c4: 00008067 ret
101c8: 00000513 li a0,0
101cc: 00008067 ret
101d0: 00000513 li a0,0
101d4: 00008067 ret
000101d8 <main>:
101d8: fa010113 addi sp,sp,-96
101dc: 04112e23 sw ra,92(sp)
101e0: 04812c23 sw s0,88(sp)
101e4: 04912a23 sw s1,84(sp)
101e8: 05212823 sw s2,80(sp)
101ec: 00200793 li a5,2
101f0: 04f12423 sw a5,72(sp)
101f4: 00600793 li a5,6
101f8: 04f12623 sw a5,76(sp)
101fc: 000217b7 lui a5,0x21
10200: 79c78793 addi a5,a5,1948 # 2179c <__clzsi2+0xc8>
10204: 0007ae03 lw t3,0(a5)
10208: 0047a303 lw t1,4(a5)
1020c: 0087a883 lw a7,8(a5)
10210: 00c7a803 lw a6,12(a5)
10214: 0107a503 lw a0,16(a5)
10218: 0147a583 lw a1,20(a5)
1021c: 0187a603 lw a2,24(a5)
10220: 01c7a683 lw a3,28(a5)
10224: 0207a703 lw a4,32(a5)
10228: 03c12223 sw t3,36(sp)
1022c: 02612423 sw t1,40(sp)
10230: 03112623 sw a7,44(sp)
10234: 03012823 sw a6,48(sp)
10238: 02a12a23 sw a0,52(sp)
1023c: 02b12c23 sw a1,56(sp)
10240: 02c12e23 sw a2,60(sp)
10244: 04d12023 sw a3,64(sp)
10248: 04e12223 sw a4,68(sp)
1024c: 0247a503 lw a0,36(a5)
10250: 0287a583 lw a1,40(a5)
10254: 02c7a603 lw a2,44(a5)
10258: 0307a683 lw a3,48(a5)
1025c: 0347a703 lw a4,52(a5)
10260: 0387a783 lw a5,56(a5)
10264: 00a12623 sw a0,12(sp)
10268: 00b12823 sw a1,16(sp)
1026c: 00c12a23 sw a2,20(sp)
10270: 00d12c23 sw a3,24(sp)
10274: 00e12e23 sw a4,28(sp)
10278: 02f12023 sw a5,32(sp)
1027c: 00200593 li a1,2
10280: 04810513 addi a0,sp,72
10284: f01ff0ef jal ra,10184 <threeConsecutiveOdds>
10288: 00050913 mv s2,a0
1028c: 00900593 li a1,9
10290: 02410513 addi a0,sp,36
10294: ef1ff0ef jal ra,10184 <threeConsecutiveOdds>
10298: 00050493 mv s1,a0
1029c: 00600593 li a1,6
102a0: 00c10513 addi a0,sp,12
102a4: ee1ff0ef jal ra,10184 <threeConsecutiveOdds>
102a8: 00050413 mv s0,a0
102ac: 00090593 mv a1,s2
102b0: 00021537 lui a0,0x21
102b4: 76050513 addi a0,a0,1888 # 21760 <__clzsi2+0x8c>
102b8: 260000ef jal ra,10518 <printf>
102bc: 00048593 mv a1,s1
102c0: 00021537 lui a0,0x21
102c4: 77450513 addi a0,a0,1908 # 21774 <__clzsi2+0xa0>
102c8: 250000ef jal ra,10518 <printf>
102cc: 00040593 mv a1,s0
102d0: 00021537 lui a0,0x21
102d4: 78850513 addi a0,a0,1928 # 21788 <__clzsi2+0xb4>
102d8: 240000ef jal ra,10518 <printf>
102dc: 00000513 li a0,0
102e0: 05c12083 lw ra,92(sp)
102e4: 05812403 lw s0,88(sp)
102e8: 05412483 lw s1,84(sp)
102ec: 05012903 lw s2,80(sp)
102f0: 06010113 addi sp,sp,96
102f4: 00008067 ret
```
O2
```RISCV
000100c4 <main>:
100c4: 000217b7 lui a5,0x21
100c8: fb010113 addi sp,sp,-80
100cc: 7c478793 addi a5,a5,1988 # 217c4 <__clzsi2+0xc8>
100d0: 0087a383 lw t2,8(a5)
100d4: 00c7a283 lw t0,12(a5)
100d8: 0107af83 lw t6,16(a5)
100dc: 0147af03 lw t5,20(a5)
100e0: 0187ae83 lw t4,24(a5)
100e4: 01c7ae03 lw t3,28(a5)
100e8: 0207a303 lw t1,32(a5)
100ec: 0247a883 lw a7,36(a5)
100f0: 0287a803 lw a6,40(a5)
100f4: 02c7a603 lw a2,44(a5)
100f8: 0307a683 lw a3,48(a5)
100fc: 0347a703 lw a4,52(a5)
10100: 04812423 sw s0,72(sp)
10104: 04912223 sw s1,68(sp)
10108: 0047a403 lw s0,4(a5)
1010c: 0007a483 lw s1,0(a5)
10110: 0387a783 lw a5,56(a5)
10114: 04112623 sw ra,76(sp)
10118: 02712223 sw t2,36(sp)
1011c: 02512423 sw t0,40(sp)
10120: 03f12623 sw t6,44(sp)
10124: 03e12823 sw t5,48(sp)
10128: 03d12a23 sw t4,52(sp)
1012c: 03c12c23 sw t3,56(sp)
10130: 02612e23 sw t1,60(sp)
10134: 01112223 sw a7,4(sp)
10138: 01012423 sw a6,8(sp)
1013c: 00c12623 sw a2,12(sp)
10140: 00d12823 sw a3,16(sp)
10144: 00e12a23 sw a4,20(sp)
10148: 00912e23 sw s1,28(sp)
1014c: 02812023 sw s0,32(sp)
10150: 00900593 li a1,9
10154: 01c10513 addi a0,sp,28
10158: 00f12c23 sw a5,24(sp)
1015c: 120000ef jal ra,1027c <threeConsecutiveOdds.part.0>
10160: 00050493 mv s1,a0
10164: 00600593 li a1,6
10168: 00410513 addi a0,sp,4
1016c: 110000ef jal ra,1027c <threeConsecutiveOdds.part.0>
10170: 00050413 mv s0,a0
10174: 00021537 lui a0,0x21
10178: 00000593 li a1,0
1017c: 78850513 addi a0,a0,1928 # 21788 <__clzsi2+0x8c>
10180: 3c0000ef jal ra,10540 <printf>
10184: 00021537 lui a0,0x21
10188: 00048593 mv a1,s1
1018c: 79c50513 addi a0,a0,1948 # 2179c <__clzsi2+0xa0>
10190: 3b0000ef jal ra,10540 <printf>
10194: 00021537 lui a0,0x21
10198: 00040593 mv a1,s0
1019c: 7b050513 addi a0,a0,1968 # 217b0 <__clzsi2+0xb4>
101a0: 3a0000ef jal ra,10540 <printf>
101a4: 04c12083 lw ra,76(sp)
101a8: 04812403 lw s0,72(sp)
101ac: 04412483 lw s1,68(sp)
101b0: 00000513 li a0,0
101b4: 05010113 addi sp,sp,80
101b8: 00008067 ret
0001027c <threeConsecutiveOdds.part.0>:
1027c: 04b05063 blez a1,102bc <threeConsecutiveOdds.part.0+0x40>
10280: 00000713 li a4,0
10284: 00000693 li a3,0
10288: 00300613 li a2,3
1028c: 0100006f j 1029c <threeConsecutiveOdds.part.0+0x20>
10290: 02c70a63 beq a4,a2,102c4 <threeConsecutiveOdds.part.0+0x48>
10294: 00450513 addi a0,a0,4
10298: 02b68263 beq a3,a1,102bc <threeConsecutiveOdds.part.0+0x40>
1029c: 00052783 lw a5,0(a0)
102a0: 00168693 addi a3,a3,1
102a4: 00170713 addi a4,a4,1
102a8: 0017f793 andi a5,a5,1
102ac: fe0792e3 bnez a5,10290 <threeConsecutiveOdds.part.0+0x14>
102b0: 00000713 li a4,0
102b4: 00450513 addi a0,a0,4
102b8: feb692e3 bne a3,a1,1029c <threeConsecutiveOdds.part.0+0x20>
102bc: 00000513 li a0,0
102c0: 00008067 ret
102c4: 00100513 li a0,1
102c8: 00008067 ret
000102cc <threeConsecutiveOdds>:
102cc: 00200793 li a5,2
102d0: 04b7d063 bge a5,a1,10310 <threeConsecutiveOdds+0x44>
102d4: 00000713 li a4,0
102d8: 00000693 li a3,0
102dc: 00300613 li a2,3
102e0: 0100006f j 102f0 <threeConsecutiveOdds+0x24>
102e4: 02c70a63 beq a4,a2,10318 <threeConsecutiveOdds+0x4c>
102e8: 00450513 addi a0,a0,4
102ec: 02d58263 beq a1,a3,10310 <threeConsecutiveOdds+0x44>
102f0: 00052783 lw a5,0(a0)
102f4: 00168693 addi a3,a3,1
102f8: 00170713 addi a4,a4,1
102fc: 0017f793 andi a5,a5,1
10300: fe0792e3 bnez a5,102e4 <threeConsecutiveOdds+0x18>
10304: 00000713 li a4,0
10308: 00450513 addi a0,a0,4
1030c: fed592e3 bne a1,a3,102f0 <threeConsecutiveOdds+0x24>
10310: 00000513 li a0,0
10314: 00008067 ret
10318: 00100513 li a0,1
1031c: 00008067 ret
```
O3
```RISCV
000100c4 <main>:
100c4: 000217b7 lui a5,0x21
100c8: fb010113 addi sp,sp,-80
100cc: 7c478793 addi a5,a5,1988 # 217c4 <__clzsi2+0xc8>
100d0: 0087a383 lw t2,8(a5)
100d4: 00c7a283 lw t0,12(a5)
100d8: 0107af83 lw t6,16(a5)
100dc: 0147af03 lw t5,20(a5)
100e0: 0187ae83 lw t4,24(a5)
100e4: 01c7ae03 lw t3,28(a5)
100e8: 0207a303 lw t1,32(a5)
100ec: 0247a883 lw a7,36(a5)
100f0: 0287a803 lw a6,40(a5)
100f4: 02c7a603 lw a2,44(a5)
100f8: 0307a683 lw a3,48(a5)
100fc: 0347a703 lw a4,52(a5)
10100: 04812423 sw s0,72(sp)
10104: 04912223 sw s1,68(sp)
10108: 0047a403 lw s0,4(a5)
1010c: 0007a483 lw s1,0(a5)
10110: 0387a783 lw a5,56(a5)
10114: 04112623 sw ra,76(sp)
10118: 02712223 sw t2,36(sp)
1011c: 02512423 sw t0,40(sp)
10120: 03f12623 sw t6,44(sp)
10124: 03e12823 sw t5,48(sp)
10128: 03d12a23 sw t4,52(sp)
1012c: 03c12c23 sw t3,56(sp)
10130: 02612e23 sw t1,60(sp)
10134: 01112223 sw a7,4(sp)
10138: 01012423 sw a6,8(sp)
1013c: 00c12623 sw a2,12(sp)
10140: 00d12823 sw a3,16(sp)
10144: 00e12a23 sw a4,20(sp)
10148: 00912e23 sw s1,28(sp)
1014c: 02812023 sw s0,32(sp)
10150: 00900593 li a1,9
10154: 01c10513 addi a0,sp,28
10158: 00f12c23 sw a5,24(sp)
1015c: 120000ef jal ra,1027c <threeConsecutiveOdds.part.0>
10160: 00050493 mv s1,a0
10164: 00600593 li a1,6
10168: 00410513 addi a0,sp,4
1016c: 110000ef jal ra,1027c <threeConsecutiveOdds.part.0>
10170: 00050413 mv s0,a0
10174: 00021537 lui a0,0x21
10178: 00000593 li a1,0
1017c: 78850513 addi a0,a0,1928 # 21788 <__clzsi2+0x8c>
10180: 3c0000ef jal ra,10540 <printf>
10184: 00021537 lui a0,0x21
10188: 00048593 mv a1,s1
1018c: 79c50513 addi a0,a0,1948 # 2179c <__clzsi2+0xa0>
10190: 3b0000ef jal ra,10540 <printf>
10194: 00021537 lui a0,0x21
10198: 00040593 mv a1,s0
1019c: 7b050513 addi a0,a0,1968 # 217b0 <__clzsi2+0xb4>
101a0: 3a0000ef jal ra,10540 <printf>
101a4: 04c12083 lw ra,76(sp)
101a8: 04812403 lw s0,72(sp)
101ac: 04412483 lw s1,68(sp)
101b0: 00000513 li a0,0
101b4: 05010113 addi sp,sp,80
101b8: 00008067 ret
0001027c <threeConsecutiveOdds.part.0>:
1027c: 04b05063 blez a1,102bc <threeConsecutiveOdds.part.0+0x40>
10280: 00000713 li a4,0
10284: 00000693 li a3,0
10288: 00300613 li a2,3
1028c: 0100006f j 1029c <threeConsecutiveOdds.part.0+0x20>
10290: 02c70a63 beq a4,a2,102c4 <threeConsecutiveOdds.part.0+0x48>
10294: 00450513 addi a0,a0,4
10298: 02b68263 beq a3,a1,102bc <threeConsecutiveOdds.part.0+0x40>
1029c: 00052783 lw a5,0(a0)
102a0: 00168693 addi a3,a3,1
102a4: 00170713 addi a4,a4,1
102a8: 0017f793 andi a5,a5,1
102ac: fe0792e3 bnez a5,10290 <threeConsecutiveOdds.part.0+0x14>
102b0: 00000713 li a4,0
102b4: 00450513 addi a0,a0,4
102b8: feb692e3 bne a3,a1,1029c <threeConsecutiveOdds.part.0+0x20>
102bc: 00000513 li a0,0
102c0: 00008067 ret
102c4: 00100513 li a0,1
102c8: 00008067 ret
000102cc <threeConsecutiveOdds>:
102cc: 00200793 li a5,2
102d0: 04b7d063 bge a5,a1,10310 <threeConsecutiveOdds+0x44>
102d4: 00000713 li a4,0
102d8: 00000693 li a3,0
102dc: 00300613 li a2,3
102e0: 0100006f j 102f0 <threeConsecutiveOdds+0x24>
102e4: 02c70a63 beq a4,a2,10318 <threeConsecutiveOdds+0x4c>
102e8: 00450513 addi a0,a0,4
102ec: 02d58263 beq a1,a3,10310 <threeConsecutiveOdds+0x44>
102f0: 00052783 lw a5,0(a0)
102f4: 00168693 addi a3,a3,1
102f8: 00170713 addi a4,a4,1
102fc: 0017f793 andi a5,a5,1
10300: fe0792e3 bnez a5,102e4 <threeConsecutiveOdds+0x18>
10304: 00000713 li a4,0
10308: 00450513 addi a0,a0,4
1030c: fed592e3 bne a1,a3,102f0 <threeConsecutiveOdds+0x24>
10310: 00000513 li a0,0
10314: 00008067 ret
10318: 00100513 li a0,1
1031c: 00008067 ret
```
Os
```RISCV=
000100c4 <main>:
100c4: fb010113 addi sp,sp,-80
100c8: 000215b7 lui a1,0x21
100cc: 04812423 sw s0,72(sp)
100d0: 02400613 li a2,36
100d4: 72458413 addi s0,a1,1828 # 21724 <__clzsi2+0xc8>
100d8: 01c10513 addi a0,sp,28
100dc: 72458593 addi a1,a1,1828
100e0: 04112623 sw ra,76(sp)
100e4: 04912223 sw s1,68(sp)
100e8: 29c000ef jal ra,10384 <memcpy>
100ec: 01800613 li a2,24
100f0: 02440593 addi a1,s0,36
100f4: 00410513 addi a0,sp,4
100f8: 28c000ef jal ra,10384 <memcpy>
100fc: 00900593 li a1,9
10100: 01c10513 addi a0,sp,28
10104: 120000ef jal ra,10224 <threeConsecutiveOdds.part.0>
10108: 00050493 mv s1,a0
1010c: 00600593 li a1,6
10110: 00410513 addi a0,sp,4
10114: 110000ef jal ra,10224 <threeConsecutiveOdds.part.0>
10118: 00050413 mv s0,a0
1011c: 00021537 lui a0,0x21
10120: 00000593 li a1,0
10124: 6e850513 addi a0,a0,1768 # 216e8 <__clzsi2+0x8c>
10128: 51c000ef jal ra,10644 <printf>
1012c: 00021537 lui a0,0x21
10130: 00048593 mv a1,s1
10134: 6fc50513 addi a0,a0,1788 # 216fc <__clzsi2+0xa0>
10138: 50c000ef jal ra,10644 <printf>
1013c: 00021537 lui a0,0x21
10140: 00040593 mv a1,s0
10144: 71050513 addi a0,a0,1808 # 21710 <__clzsi2+0xb4>
10148: 4fc000ef jal ra,10644 <printf>
1014c: 04c12083 lw ra,76(sp)
10150: 04812403 lw s0,72(sp)
10154: 04412483 lw s1,68(sp)
10158: 00000513 li a0,0
1015c: 05010113 addi sp,sp,80
10160: 00008067 ret
00010224 <threeConsecutiveOdds.part.0>:
10224: 00000693 li a3,0
10228: 00000713 li a4,0
1022c: 00300613 li a2,3
10230: 00b74663 blt a4,a1,1023c <threeConsecutiveOdds.part.0+0x18>
10234: 00000513 li a0,0
10238: 00008067 ret
1023c: 00271793 slli a5,a4,0x2
10240: 00f507b3 add a5,a0,a5
10244: 0007a783 lw a5,0(a5)
10248: 0017f793 andi a5,a5,1
1024c: 00078663 beqz a5,10258 <threeConsecutiveOdds.part.0+0x34>
10250: 00168793 addi a5,a3,1
10254: 00c78863 beq a5,a2,10264 <threeConsecutiveOdds.part.0+0x40>
10258: 00170713 addi a4,a4,1
1025c: 00078693 mv a3,a5
10260: fd1ff06f j 10230 <threeConsecutiveOdds.part.0+0xc>
10264: 00100513 li a0,1
10268: 00008067 ret
0001026c <threeConsecutiveOdds>:
1026c: 00200793 li a5,2
10270: 00b7d463 bge a5,a1,10278 <threeConsecutiveOdds+0xc>
10274: fb1ff06f j 10224 <threeConsecutiveOdds.part.0>
10278: 00000513 li a0,0
1027c: 00008067 ret
```
Ofast
```RISCV
000100c4 <main>:
100c4: 000217b7 lui a5,0x21
100c8: fb010113 addi sp,sp,-80
100cc: 7c478793 addi a5,a5,1988 # 217c4 <__clzsi2+0xc8>
100d0: 0087a383 lw t2,8(a5)
100d4: 00c7a283 lw t0,12(a5)
100d8: 0107af83 lw t6,16(a5)
100dc: 0147af03 lw t5,20(a5)
100e0: 0187ae83 lw t4,24(a5)
100e4: 01c7ae03 lw t3,28(a5)
100e8: 0207a303 lw t1,32(a5)
100ec: 0247a883 lw a7,36(a5)
100f0: 0287a803 lw a6,40(a5)
100f4: 02c7a603 lw a2,44(a5)
100f8: 0307a683 lw a3,48(a5)
100fc: 0347a703 lw a4,52(a5)
10100: 04812423 sw s0,72(sp)
10104: 04912223 sw s1,68(sp)
10108: 0047a403 lw s0,4(a5)
1010c: 0007a483 lw s1,0(a5)
10110: 0387a783 lw a5,56(a5)
10114: 04112623 sw ra,76(sp)
10118: 02712223 sw t2,36(sp)
1011c: 02512423 sw t0,40(sp)
10120: 03f12623 sw t6,44(sp)
10124: 03e12823 sw t5,48(sp)
10128: 03d12a23 sw t4,52(sp)
1012c: 03c12c23 sw t3,56(sp)
10130: 02612e23 sw t1,60(sp)
10134: 01112223 sw a7,4(sp)
10138: 01012423 sw a6,8(sp)
1013c: 00c12623 sw a2,12(sp)
10140: 00d12823 sw a3,16(sp)
10144: 00e12a23 sw a4,20(sp)
10148: 00912e23 sw s1,28(sp)
1014c: 02812023 sw s0,32(sp)
10150: 00900593 li a1,9
10154: 01c10513 addi a0,sp,28
10158: 00f12c23 sw a5,24(sp)
1015c: 120000ef jal ra,1027c <threeConsecutiveOdds.part.0>
10160: 00050493 mv s1,a0
10164: 00600593 li a1,6
10168: 00410513 addi a0,sp,4
1016c: 110000ef jal ra,1027c <threeConsecutiveOdds.part.0>
10170: 00050413 mv s0,a0
10174: 00021537 lui a0,0x21
10178: 00000593 li a1,0
1017c: 78850513 addi a0,a0,1928 # 21788 <__clzsi2+0x8c>
10180: 3c0000ef jal ra,10540 <printf>
10184: 00021537 lui a0,0x21
10188: 00048593 mv a1,s1
1018c: 79c50513 addi a0,a0,1948 # 2179c <__clzsi2+0xa0>
10190: 3b0000ef jal ra,10540 <printf>
10194: 00021537 lui a0,0x21
10198: 00040593 mv a1,s0
1019c: 7b050513 addi a0,a0,1968 # 217b0 <__clzsi2+0xb4>
101a0: 3a0000ef jal ra,10540 <printf>
101a4: 04c12083 lw ra,76(sp)
101a8: 04812403 lw s0,72(sp)
101ac: 04412483 lw s1,68(sp)
101b0: 00000513 li a0,0
101b4: 05010113 addi sp,sp,80
101b8: 00008067 ret
0001027c <threeConsecutiveOdds.part.0>:
1027c: 04b05063 blez a1,102bc <threeConsecutiveOdds.part.0+0x40>
10280: 00000713 li a4,0
10284: 00000693 li a3,0
10288: 00300613 li a2,3
1028c: 0100006f j 1029c <threeConsecutiveOdds.part.0+0x20>
10290: 02c70a63 beq a4,a2,102c4 <threeConsecutiveOdds.part.0+0x48>
10294: 00450513 addi a0,a0,4
10298: 02b68263 beq a3,a1,102bc <threeConsecutiveOdds.part.0+0x40>
1029c: 00052783 lw a5,0(a0)
102a0: 00168693 addi a3,a3,1
102a4: 00170713 addi a4,a4,1
102a8: 0017f793 andi a5,a5,1
102ac: fe0792e3 bnez a5,10290 <threeConsecutiveOdds.part.0+0x14>
102b0: 00000713 li a4,0
102b4: 00450513 addi a0,a0,4
102b8: feb692e3 bne a3,a1,1029c <threeConsecutiveOdds.part.0+0x20>
102bc: 00000513 li a0,0
102c0: 00008067 ret
102c4: 00100513 li a0,1
102c8: 00008067 ret
000102cc <threeConsecutiveOdds>:
102cc: 00200793 li a5,2
102d0: 04b7d063 bge a5,a1,10310 <threeConsecutiveOdds+0x44>
102d4: 00000713 li a4,0
102d8: 00000693 li a3,0
102dc: 00300613 li a2,3
102e0: 0100006f j 102f0 <threeConsecutiveOdds+0x24>
102e4: 02c70a63 beq a4,a2,10318 <threeConsecutiveOdds+0x4c>
102e8: 00450513 addi a0,a0,4
102ec: 02d58263 beq a1,a3,10310 <threeConsecutiveOdds+0x44>
102f0: 00052783 lw a5,0(a0)
102f4: 00168693 addi a3,a3,1
102f8: 00170713 addi a4,a4,1
102fc: 0017f793 andi a5,a5,1
10300: fe0792e3 bnez a5,102e4 <threeConsecutiveOdds+0x18>
10304: 00000713 li a4,0
10308: 00450513 addi a0,a0,4
1030c: fed592e3 bne a1,a3,102f0 <threeConsecutiveOdds+0x24>
10310: 00000513 li a0,0
10314: 00008067 ret
10318: 00100513 li a0,1
1031c: 00008067 ret
```
## **Reference:**
[Lab2: RISC-V RV32I[MACF] emulator with ELF support](https://hackmd.io/@sysprog/SJAR5XMmi)
[Assignment2: RISC-V Toolchain](https://hackmd.io/@sysprog/2022-arch-homework2)
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