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Jim Huang2023/10/29 04:08:36
Assignment2: RISC-V Toolchain
contributed by <hugo0406>
Select a Subject
The following subject is picked from the Assignment 1
林柏全 Finding First String of 1-bits of a given length by CLZ
Subject description: Find the first consecutive 1-bits string with a length of n.
Motivation: The reason why I chose this subject as my assignment 2 is that I have a interest in topics like string searching
The original C implementation of the subject is as follows.
Source Code
uint16_t count_leading_zeros(uint64_t x)
{
x |= (x >> 1);
x |= (x >> 2);
x |= (x >> 4);
x |= (x >> 8);
x |= (x >> 16);
x |= (x >> 32);
x -= ((x >> 1) & 0x5555555555555555);
x = ((x >> 2) & 0x3333333333333333) + (x & 0x3333333333333333);
x = ((x >> 4) + x) & 0x0f0f0f0f0f0f0f0f;
x += (x >> 8);
x += (x >> 16);
x += (x >> 32);
return (64 - (x & 0x7f));
}
int find_string(uint64_t x, int n){
int clz; // numbers of consecutive leading bits (0 or 1)
int pos = 0; // position of first '1' bit in consecutive '1' bit string from significant bit
while(x != 0){
clz = count_leading_zeros(x);
x = x << clz;
pos = pos + clz;
clz = count_leading_zeros(~x);
if (clz >= n)
return pos;
x = x << clz;
pos = pos + clz;
}
return -1;
}
int main() {
uint64_t test_data[] = {0x0f00000000000000,
0x0000000000000000,
0x0123456789abcdef};
for (int i = 0; i < 3; i++) {
uint64_t x = test_data[i];
int n = 4;
int result = find_string(x, n);
printf("Test Case %d: Input: 0x%016lx, Result: %d\n", i+1, x, result);
}
return 0;
Analysis the original C code
In order to analyze the performance of original code, I use extern functions (getcycles.s , getinstret.s) where the code in perfcounter to get current clock cycle and current instrution count.Then,I split the original C code into two C files(main.c , func.c).
In main.c, there is only the main function ,while in func.c, there are all the other functions.
main.c
#include <stdint.h>
#include <stdio.h>
extern uint64_t get_cycles();
extern uint64_t get_instret();
extern int find_string(uint64_t x, int n);
int main()
{
int result[3];
uint64_t test_data[] = {0x0f00000000000000,
0x0000000000000000,
0x0123456789abcdef};
uint64_t instret = get_instret();
uint64_t start = get_cycles();
for (int i = 0; i < 3; i++) {
uint64_t x = test_data[i];
int n = 4;
result[i] = find_string(x, n);
}
uint64_t fin = get_instret();
uint64_t end = get_cycles();
uint64_t cyclecount = end - start;
uint64_t instrcount = fin - instret;
for (int i = 0; i < 3; i++) { printf("Test Case %d: Input: 0x%016lx, Result: %d\n", i+1, test_data[i], result[i]);}
printf("cycle count: %u\n", (unsigned int) cyclecount);
printf("instret: %u\n", (unsigned) (instrcount));
return 0;
}
func.c
#include <stdio.h>
#include <stdint.h>
/* Counting leading zeros function */
uint16_t count_leading_zeros(uint64_t x)
{
x |= (x >> 1);
x |= (x >> 2);
x |= (x >> 4);
x |= (x >> 8);
x |= (x >> 16);
x |= (x >> 32);
/* Count ones (population count) */
x -= ((x >> 1) & 0x5555555555555555);
x = ((x >> 2) & 0x3333333333333333) + (x & 0x3333333333333333);
x = ((x >> 4) + x) & 0x0f0f0f0f0f0f0f0f;
x += (x >> 8);
x += (x >> 16);
x += (x >> 32);
return (64 - (x & 0x7f));
}
int find_string(uint64_t x, int n){
int clz; // numbers of consecutive leading bits (0 or 1)
int pos = 0; // position of fist '1' bit in consecutive '1' bit string from significant bit
while(x != 0){
clz = count_leading_zeros(x);
x = x << clz;
pos = pos + clz;
clz = count_leading_zeros(~x);
if (clz >= n)
return pos;
x = x << clz;
pos = pos + clz;
}
return -1;
}
I modify a makefile where in perfcounter to compile C programs
makefile
PHONY: clean
include ../../mk/toolchain.mk
CFLAGS = -march=rv32i_zicsr_zifencei -mabi=ilp32 -O0 -Wall
OBJS = \
getcycles.o \
getinstret.o \
main.o\
func.o
BIN = main.elf
%.o: %.s
$(CROSS_COMPILE)gcc $(CFLAGS) -c -o $@ $<
%.o: %.c
$(CROSS_COMPILE)gcc $(CFLAGS) -c -o $@ $<
all: $(BIN)
$(BIN): $(OBJS)
$(CROSS_COMPILE)gcc -o $@ $^
clean:
$(RM) $(BIN) $(OBJS)
Using make to Compile C Programs
Execution on rv32emu and show the results
Display the assembler mnemonics for the machine instructions
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ riscv-none-elf-objdump -d main.elf > main.txt
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ vim main.txt
Part of disassembly code
main.elf: file format elf32-littleriscv
Disassembly of section .text:
00010094 <exit>:
10094: 1141 add sp,sp,-16
10096: 4581 li a1,0
10098: c422 sw s0,8(sp)
1009a: c606 sw ra,12(sp)
1009c: 842a mv s0,a0
1009e: 0f0010ef jal 1118e <__call_exitprocs>
100a2: f4c1a783 lw a5,-180(gp) # 1e794 <__stdio_exit_handler>
100a6: c391 beqz a5,100aa <exit+0x16>
100a8: 9782 jalr a5
100aa: 8522 mv a0,s0
100ac: 7a1090ef jal 1a04c <_exit>
...
000102a0 <count_leading_zeros>:
102a0: 01f59713 sll a4,a1,0x1f
102a4: 00155793 srl a5,a0,0x1
102a8: 00f767b3 or a5,a4,a5
102ac: 0015d713 srl a4,a1,0x1
102b0: 00a7e533 or a0,a5,a0
102b4: 00b765b3 or a1,a4,a1
102b8: 01e59713 sll a4,a1,0x1e
102bc: 00255793 srl a5,a0,0x2
102c0: 00f767b3 or a5,a4,a5
102c4: 0025d613 srl a2,a1,0x2
102c8: 00a7e533 or a0,a5,a0
102cc: 00b66633 or a2,a2,a1
102d0: 01c61713 sll a4,a2,0x1c
102d4: 00455793 srl a5,a0,0x4
102d8: 00f767b3 or a5,a4,a5
102dc: 00465693 srl a3,a2,0x4
102e0: 00a7e733 or a4,a5,a0
102e4: 00c6e6b3 or a3,a3,a2
102e8: 01869613 sll a2,a3,0x18
102ec: 00875793 srl a5,a4,0x8
102f0: 00f667b3 or a5,a2,a5
102f4: 0086d613 srl a2,a3,0x8
102f8: 00e7e7b3 or a5,a5,a4
102fc: 00d66633 or a2,a2,a3
10300: 01061713 sll a4,a2,0x10
10304: 0107d693 srl a3,a5,0x10
10308: 00d766b3 or a3,a4,a3
1030c: 01065713 srl a4,a2,0x10
10310: 00f6e6b3 or a3,a3,a5
10314: 00c76733 or a4,a4,a2
10318: 00d766b3 or a3,a4,a3
1031c: 01f71613 sll a2,a4,0x1f
10320: 0016d793 srl a5,a3,0x1
10324: 00f667b3 or a5,a2,a5
10328: 00175593 srl a1,a4,0x1
1032c: 55555637 lui a2,0x55555
10330: 55560613 add a2,a2,1365 # 55555555 <__BSS_END__+0x55537805>
10334: 00c7f7b3 and a5,a5,a2
10338: 00c5f633 and a2,a1,a2
1033c: 40f687b3 sub a5,a3,a5
10340: 00f6b6b3 sltu a3,a3,a5
10344: 40c70733 sub a4,a4,a2
10348: 40d70733 sub a4,a4,a3
1034c: 01e71613 sll a2,a4,0x1e
10350: 0027d693 srl a3,a5,0x2
10354: 00d666b3 or a3,a2,a3
10358: 00275593 srl a1,a4,0x2
1035c: 33333637 lui a2,0x33333
10360: 33360613 add a2,a2,819 # 33333333 <__BSS_END__+0x333155e3>
10364: 00c6f6b3 and a3,a3,a2
10368: 00c5f5b3 and a1,a1,a2
1036c: 00c7f7b3 and a5,a5,a2
10370: 00c77733 and a4,a4,a2
10374: 00f687b3 add a5,a3,a5
10378: 00d7b6b3 sltu a3,a5,a3
1037c: 00e58733 add a4,a1,a4
10380: 00e686b3 add a3,a3,a4
10384: 01c69613 sll a2,a3,0x1c
10388: 0047d713 srl a4,a5,0x4
1038c: 00e66733 or a4,a2,a4
10390: 0046d613 srl a2,a3,0x4
10394: 00f707b3 add a5,a4,a5
10398: 00e7b733 sltu a4,a5,a4
1039c: 00d606b3 add a3,a2,a3
103a0: 00d70733 add a4,a4,a3
103a4: 0f0f16b7 lui a3,0xf0f1
103a8: f0f68693 add a3,a3,-241 # f0f0f0f <__BSS_END__+0xf0d31bf>
103ac: 00d7f7b3 and a5,a5,a3
103b0: 00d77733 and a4,a4,a3
103b4: 01871613 sll a2,a4,0x18
103b8: 0087d693 srl a3,a5,0x8
103bc: 00d666b3 or a3,a2,a3
103c0: 00875613 srl a2,a4,0x8
103c4: 00f687b3 add a5,a3,a5
103c8: 00d7b6b3 sltu a3,a5,a3
103cc: 00e60733 add a4,a2,a4
103d0: 00e686b3 add a3,a3,a4
103d4: 01069613 sll a2,a3,0x10
103d8: 0107d713 srl a4,a5,0x10
103dc: 00e66733 or a4,a2,a4
103e0: 0106d613 srl a2,a3,0x10
103e4: 00f707b3 add a5,a4,a5
103e8: 00e7b733 sltu a4,a5,a4
103ec: 00d606b3 add a3,a2,a3
103f0: 00d70733 add a4,a4,a3
103f4: 00f70733 add a4,a4,a5
103f8: 07f77713 and a4,a4,127
103fc: 04000513 li a0,64
10400: 40e50533 sub a0,a0,a4
10404: 01051513 sll a0,a0,0x10
10408: 01055513 srl a0,a0,0x10
1040c: 00008067 ret
00010410 <find_string>:
10410: fe010113 add sp,sp,-32
10414: 00112e23 sw ra,28(sp)
10418: 00812c23 sw s0,24(sp)
1041c: 00b567b3 or a5,a0,a1
10420: 0c078e63 beqz a5,104fc <find_string+0xec>
10424: 00912a23 sw s1,20(sp)
10428: 01212823 sw s2,16(sp)
1042c: 01312623 sw s3,12(sp)
10430: 01412423 sw s4,8(sp)
10434: 01512223 sw s5,4(sp)
10438: 01612023 sw s6,0(sp)
1043c: 00050493 mv s1,a0
10440: 00058913 mv s2,a1
10444: 00060a13 mv s4,a2
10448: 00000413 li s0,0
1044c: 01f00b13 li s6,31
10450: 00000a93 li s5,0
10454: 0440006f j 10498 <find_string+0x88>
10458: 0014d793 srl a5,s1,0x1
1045c: 40ab0733 sub a4,s6,a0
10460: 00e7d7b3 srl a5,a5,a4
10464: 00a919b3 sll s3,s2,a0
10468: 0137e9b3 or s3,a5,s3
1046c: 00a494b3 sll s1,s1,a0
10470: 0440006f j 104b4 <find_string+0xa4>
10474: 0014d793 srl a5,s1,0x1
10478: 40ab0733 sub a4,s6,a0
1047c: 00e7d7b3 srl a5,a5,a4
10480: 00a99933 sll s2,s3,a0
10484: 0127e933 or s2,a5,s2
10488: 00a494b3 sll s1,s1,a0
1048c: 00a40433 add s0,s0,a0
10490: 0124e7b3 or a5,s1,s2
10494: 04078463 beqz a5,104dc <find_string+0xcc>
10498: 00048513 mv a0,s1
1049c: 00090593 mv a1,s2
104a0: e01ff0ef jal 102a0 <count_leading_zeros>
104a4: fe050993 add s3,a0,-32
104a8: fa09c8e3 bltz s3,10458 <find_string+0x48>
104ac: 013499b3 sll s3,s1,s3
104b0: 000a8493 mv s1,s5
104b4: 00850433 add s0,a0,s0
104b8: fff4c513 not a0,s1
104bc: fff9c593 not a1,s3
104c0: de1ff0ef jal 102a0 <count_leading_zeros>
104c4: 05455063 bge a0,s4,10504 <find_string+0xf4>
104c8: fe050913 add s2,a0,-32
104cc: fa0944e3 bltz s2,10474 <find_string+0x64>
104d0: 01249933 sll s2,s1,s2
104d4: 000a8493 mv s1,s5
104d8: fb5ff06f j 1048c <find_string+0x7c>
104dc: fff00413 li s0,-1
104e0: 01412483 lw s1,20(sp)
104e4: 01012903 lw s2,16(sp)
104e8: 00c12983 lw s3,12(sp)
104ec: 00812a03 lw s4,8(sp)
104f0: 00412a83 lw s5,4(sp)
104f4: 00012b03 lw s6,0(sp)
104f8: 0240006f j 1051c <find_string+0x10c>
104fc: fff00413 li s0,-1
10500: 01c0006f j 1051c <find_string+0x10c>
10504: 01412483 lw s1,20(sp)
10508: 01012903 lw s2,16(sp)
1050c: 00c12983 lw s3,12(sp)
10510: 00812a03 lw s4,8(sp)
10514: 00412a83 lw s5,4(sp)
10518: 00012b03 lw s6,0(sp)
1051c: 00040513 mv a0,s0
10520: 01c12083 lw ra,28(sp)
10524: 01812403 lw s0,24(sp)
10528: 02010113 add sp,sp,32
1052c: 00008067 ret
...
Display the ELF file header
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ riscv-none-elf-readelf -h main.elf
ELF Header:
Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: RISC-V
Version: 0x1
Entry point address: 0x100c4
Start of program headers: 52 (bytes into file)
Start of section headers: 69548 (bytes into file)
Flags: 0x1, RVC, soft-float ABI
Size of this header: 52 (bytes)
Size of program headers: 32 (bytes)
Number of program headers: 3
Size of section headers: 40 (bytes)
Number of section headers: 15
Section header string table index: 14
List the section sizes and the total size for main.elf
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ riscv-none-elf-size main.elf
text data bss dec hex filename
53148 1876 1528 56552 dce8 main.elf
Adapt the original assembly code
Origignal Assembly Code
.data
t1_u: .word 0x0f000000 # upper bits of test data 1, test_data1[0~31]
t1_l: .word 0x00000000 # lower bits of test data 2, test_data2[32~63]
t2_u: .word 0x00000000
t2_l: .word 0x00000000
t3_u: .word 0x01234567
t3_l: .word 0x89abcdef
.text
main:
# initial setting
la t0, t1_u # load address of upper bits of test data 1 into s0
la t1, t2_u
la t2, t3_u
addi sp, sp, -12
sw t0, 0(sp)
sw t1, 4(sp)
sw t2, 8(sp)
add s0, zero, t0 # s0 = & test_data_upper
add s1, zero, zero # int i (used for test data loop control)
addi s2, zero, 3 # upper bound of i (used for loop control)
addi s3, zero, 4
addi s4, zero, -1 # be used to do not operation
main_for_loop:
# call finding_string procedure
#mv a0, s0 # a0 = & test_data_1_upper
jal ra, fs
li a7, 1
ecall
li a0, 0
li a7, 11
ecall
addi s1, s1, 1
addi s0, s0, 8
blt s1, s2, -12
li a7, 11
ecall
j Exit
fs:
addi sp, sp, -16
sw ra, 0(sp)
sw s1, 4(sp)
sw s2, 8(sp)
sw s3, 12(sp)
#sw s4, 16(sp)
addi s1, s0, 4 # s1 = & test_date_lower
lw a1, 0(s0) # a1 = value of test_data upper
lw a2, 0(s1) # a2 = value of test_date lower, test_data = [a1, a2]
#li s2, 0 # s2 = clz = 0
li s2, 0 # s2 = pos = 0
x_equal_0_check:
bne a1, zero, x_not_equal_0
bne a2, zero, x_not_equal_0
x_eqaul_0:
addi a0, zero, -1
j fs_end
x_not_equal_0:
jal ra, CLZ
# x = x << clz
li t0, 32
sub t0, t0, a0
srl a4, a2, t0
sll a3, a1, a0
or a3, a3, a4 # a1 = a1 << clz
sll a4, a2, a0 # a2 = a2 << clz, x([a3, a4]) = x([a1, a2]) << clz
# pos = pos + clz
add s2, s2, a0
# x = -x, [a3, a4] = - [a1, a2]
xor a1, a3, s4
xor a2, a4, s4
jal ra, CLZ
# check: clz > n
bge a0, s3, 32
## < case
# x = x << clz
sub t0, t0, a0
srl a2, a4, t0
sll a1, a3, a0
or a1, a1, a2 # a1 = a3 << clz
sll a2, a4, a0 # a2 = a4 << clz, x([a1, a2]) = x([a3, a4]) << clz
# pos = pos + clz
add s2, s2, a0
j x_equal_0_check
## >= base
mv a0, s2
j fs_end
fs_end:
lw ra, 0(sp)
lw s1, 4(sp)
lw s2, 8(sp)
lw s3, 12(sp)
addi sp, sp, 16
jalr ra
CLZ:
addi sp, sp, -4
sw ra, 0(sp)
mv t0, a1
mv t1, a2
li t4, 0x55555555
li t5, 0x33333333
li t6, 0x0f0f0f0f
# x |= (x>>1);
srli t3, t1, 1 # shift lower bits of test data right with 1 bit
slli t2, t0, 31 # shift upper bits of test data left with 31 bits
or t3, t2, t3 # combine to get new lower bits of test data
srli t2, t0, 1 # shift upper bound of test data right with 1 bit
or t0, t0, t2 # [0~31]x | [0~31](x >> 1)
or t1, t1, t3 # [32~63]x | [32~63](x >> 1)
# x |= (x>>2);
srli t3, t1, 2
slli t2, t0, 30
or t3, t2, t3
srli t2, t0, 2
or t0, t0, t2
or t1, t1, t3
# x |= (x>>4);
srli t3, t1, 4
slli t2, t0, 28
or t3, t2, t3
srli t2, t0, 4
or t0, t0, t2
or t1, t1, t3
# x |= (x>>8);
srli t3, t1, 8
slli t2, t0, 24
or t3, t2, t3
srli t2, t0, 8
or t0, t0, t2
or t1, t1, t3
# x |= (x>>16);
srli t3, t1, 16
slli t2, t0, 16
or t3, t2, t3
srli t2, t0, 16
or t0, t0, t2
or t1, t1, t3
# x |= (x>>32)
li t2, 0
add t3, t0, zero
or t0, t0, t2
or t1, t1, t3
# x -= ((x>>1) & 0x5555555555555555)
## [t2, t3] = x>>1 ([t0, t1]>>1)
srli t3, t1, 1
slli t2, t0, 31
or t3, t2, t3
srli t2, t0, 1
## (x>>1) & 0x5~
and t2, t2, t4
and t3, t3, t4 # [t2, t3] = (x>>1)&0x5~
sub t3, t1, t3
blt t1, t3, 16 # if underflow then jump
add t1, t3, zero # t1=t3
sub t0, t0, t2 # no underflow at lower bits, [t0, t1]=> x -= ((x>>1) & 0x5555555555555555)
beq zero, zero, 12
addi t0, t0, -1 # underflow at lower bits
sub t0, t0, t2 #[t0, t1] => x -= ((x>>1) & 0x5555555555555555)
# x = ((x>>2)&0x333333333333333) + (x & 0x3333333333333333)
## [t2, t3] = x>>2 ([t0, t1]>>2)
srli t3, t1, 2
slli t2, t0, 30
or t3, t3, t2
srli t2, t0, 2 # [t2, t3] = x>>2
## (x>>1) & 0x3~
and t2, t2, t5
and t3, t3, t5 # [t2, t3] = ((x>>2)&0x3~)
## x & 0x3~
and t0, t0, t5
and t1, t1, t5 # [t0, t1] = (x & 0x3~)
add t1, t1, t3
add t0, t0, t2
## overflow detection (lower bits)
or t4, t1, zero
xor t4, s4, t4 # nor t5, t1, zero (t4 = ~(s4 | zero))
bgeu t4, t3, 8 # if no overflow then jump
addi t0, t0, 1 # if overflow upper bits plus 1
# x += ((x>>4)+x) & 0x0f~0f
## [t2, t3] = x>>4 ([t0, t1]>>4)
srli t3, t1, 4
slli t2, t0, 28
or t3, t3, t2
srli t2, t0, 4
## (x>>4) + x
add t1, t1, t3
add t0, t0, t2
## overflow detection (lower bits)
or t4, t1, zero
xor t4, s4, t4 # nor t5, t1, zero (t4 = ~(s4 | zero))
bgeu t4, t3, 8 # if no overflow then jump
addi t0, t0, 1 # if overflow upper bits plus 1
## ((x>>4) + x) & 0x0f~0f
and t0, t0, t6
and t1, t1, t6
# x += x(x>>8)
srli t3, t1, 8
slli t2, t0, 24
or t3, t3, t2
srli t2, t0, 8 # [t2, t3] = x>>8
add t0, t0, t2
add t1, t1, t3
## overflow detection
or t4, t1, zero
xor t4, s4, t4
bgeu t4, t3, 8
addi t0, t0, 1
# x += x(x>>16)
srli t3, t1, 16
slli t2, t0, 16
or t3, t3, t2
srli t2, t0, 16 # [t2, t3] = x>>8
add t0, t0, t2
add t1, t1, t3
## overflow detection
or t4, t1, zero
xor t4, s4, t4
bgeu t4, t3, 8
addi t0, t0, 1
# x += (x>>32)
add t3, t0, zero
add t2, zero, zero
add t0, t0, t2
add t1, t1, t3
## overflow detection
or t4, t1, zero
xor t4, s4, t4
bgeu t4, t3, 8
addi t0, t0, 1
# 64 - (x & (0x7f))
li t4, 0x7f
li a0, 64
and t1, t1, t4
sub a0, a0, t1
lw ra, 0(sp)
addi sp, sp, 4
jalr ra
Exit:
nop
Optimization
-O1 Optimization
execution and the result
ELF file header
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ riscv-none-elf-readelf -h main.elf
ELF Header:
Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: RISC-V
Version: 0x1
Entry point address: 0x100c2
Start of program headers: 52 (bytes into file)
Start of section headers: 69492 (bytes into file)
Flags: 0x1, RVC, soft-float ABI
Size of this header: 52 (bytes)
Size of program headers: 32 (bytes)
Number of program headers: 3
Size of section headers: 40 (bytes)
Number of section headers: 15
Section header string table index: 14
Size
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ riscv-none-elf-size main.elf
text data bss dec hex filename
52048 1876 1528 55452 d89c main.elf
-O2 Optimization
execution and the result
ELF file header
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ riscv-none-elf-readelf -h main.elf
ELF Header:
Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: RISC-V
Version: 0x1
Entry point address: 0x101f6
Start of program headers: 52 (bytes into file)
Start of section headers: 69492 (bytes into file)
Flags: 0x1, RVC, soft-float ABI
Size of this header: 52 (bytes)
Size of program headers: 32 (bytes)
Number of program headers: 3
Size of section headers: 40 (bytes)
Number of section headers: 15
Section header string table index: 14
Size
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ riscv-none-elf-size main.elf
text data bss dec hex filename
52068 1876 1528 55472 d8b0 main.elf
-O3 Optimization
execution and the result
ELF file header
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ riscv-none-elf-readelf -h main.elf
ELF Header:
Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: RISC-V
Version: 0x1
Entry point address: 0x101f6
Start of program headers: 52 (bytes into file)
Start of section headers: 69492 (bytes into file)
Flags: 0x1, RVC, soft-float ABI
Size of this header: 52 (bytes)
Size of program headers: 32 (bytes)
Number of program headers: 3
Size of section headers: 40 (bytes)
Number of section headers: 15
Section header string table index: 14
Size
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ riscv-none-elf-size main.elf
text data bss dec hex filename
52616 1876 1528 56020 dad4 main.elf
-Os Optimization
execution and the result
ELF file header
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ riscv-none-elf-readelf -h main.elf
ELF Header:
Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: RISC-V
Version: 0x1
Entry point address: 0x101d2
Start of program headers: 52 (bytes into file)
Start of section headers: 69564 (bytes into file)
Flags: 0x1, RVC, soft-float ABI
Size of this header: 52 (bytes)
Size of program headers: 32 (bytes)
Number of program headers: 3
Size of section headers: 40 (bytes)
Number of section headers: 15
Section header string table index: 14
Size
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ riscv-none-elf-size main.elf
text data bss dec hex filename
51938 1876 1528 55342 d82e main.elf
-Ofast Optimization
execution and the result
ELF file header
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ riscv-none-elf-readelf -h main.elf
ELF Header:
Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: RISC-V
Version: 0x1
Entry point address: 0x101f6
Start of program headers: 52 (bytes into file)
Start of section headers: 69492 (bytes into file)
Flags: 0x1, RVC, soft-float ABI
Size of this header: 52 (bytes)
Size of program headers: 32 (bytes)
Number of program headers: 3
Size of section headers: 40 (bytes)
Number of section headers: 15
Section header string table index: 14
Size
cychen@cychen-VirtualBox:~/rv32emu/tests/hw2$ riscv-none-elf-size main.elf
text data bss dec hex filename
52616 1876 1528 56020 dad4 main.elf
Reference
陳川曜
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