[ARM-assembly]-C语言和汇编对比学习
作者：互联网
（1）
static int x;
//static int y = 10;
//int z;
//int w = 20;
int main()
{
int s = 200;
x = 100;
s=s+x;
// s=s+y;
// z=100;
// s=s+z;
// s=s+w;
return 0;
}
hehezhou@buildsrv-165:~/workspace/test/test1$ aarch64-linux-android-objdump -D main.o
main.o: file format elf64-littleaarch64
Disassembly of section .text:
0000000000000000 <main>:
0: d10043ff sub sp, sp, #0x10
4: 52801900 mov w0, #0xc8 // #200
8: b9000fe0 str w0, [sp,#12]
c: 90000000 adrp x0, 0 <main>
10: 91000000 add x0, x0, #0x0
14: 52800c81 mov w1, #0x64 // #100
18: b9000001 str w1, [x0]
1c: 90000000 adrp x0, 0 <main>
20: 91000000 add x0, x0, #0x0
24: b9400000 ldr w0, [x0]
28: b9400fe1 ldr w1, [sp,#12]
2c: 0b000020 add w0, w1, w0
30: b9000fe0 str w0, [sp,#12]
34: 52800000 mov w0, #0x0 // #0
38: 910043ff add sp, sp, #0x10
3c: d65f03c0 ret
Disassembly of section .bss:
0000000000000000 <x>:
0: 00000000 .word 0x00000000
Disassembly of section .comment:
0000000000000000 <.comment>:
0: 43434700 .inst 0x43434700 ; undefined
4: 4728203a .inst 0x4728203a ; undefined
8: 2029554e .inst 0x2029554e ; undefined
c: 2e392e34 uqsub v20.8b, v17.8b, v25.8b
10: 30322078 adr x24, 6441d <main+0x6441d>
14: 31303531 adds w17, w9, #0xc0d
18: 28203332 stnp w18, w12, [x25,#-256]
1c: 72657270 .inst 0x72657270 ; undefined
20: 61656c65 .inst 0x61656c65 ; undefined
24: 00296573 .inst 0x00296573 ; NYI
（2）
//static int x;
static int y = 10;
//int z;
//int w = 20;
int main()
{
int s = 200;
// x = 100;
// s=s+x;
s=s+y;
// z=100;
// s=s+z;
// s=s+w;
return 0;
}
hehezhou@buildsrv-165:~/workspace/test/test1$ aarch64-linux-android-objdump -D main.o
main.o: file format elf64-littleaarch64
Disassembly of section .text:
0000000000000000 <main>:
0: d10043ff sub sp, sp, #0x10
4: 52801900 mov w0, #0xc8 // #200
8: b9000fe0 str w0, [sp,#12]
c: 90000000 adrp x0, 0 <main>
10: 91000000 add x0, x0, #0x0
14: b9400000 ldr w0, [x0]
18: b9400fe1 ldr w1, [sp,#12]
1c: 0b000020 add w0, w1, w0
20: b9000fe0 str w0, [sp,#12]
24: 52800000 mov w0, #0x0 // #0
28: 910043ff add sp, sp, #0x10
2c: d65f03c0 ret
Disassembly of section .data:
0000000000000000 <y>:
0: 0000000a .word 0x0000000a
Disassembly of section .comment:
0000000000000000 <.comment>:
0: 43434700 .inst 0x43434700 ; undefined
4: 4728203a .inst 0x4728203a ; undefined
8: 2029554e .inst 0x2029554e ; undefined
c: 2e392e34 uqsub v20.8b, v17.8b, v25.8b
10: 30322078 adr x24, 6441d <main+0x6441d>
14: 31303531 adds w17, w9, #0xc0d
18: 28203332 stnp w18, w12, [x25,#-256]
1c: 72657270 .inst 0x72657270 ; undefined
20: 61656c65 .inst 0x61656c65 ; undefined
24: 00296573 .inst 0x00296573 ; NYI
（3）、
//static int x;
//static int y = 10;
int z;
//int w = 20;
int main()
{
int s = 200;
// x = 100;
// s=s+x;
// s=s+y;
z=100;
s=s+z;
// s=s+w;
return 0;
}
hehezhou@buildsrv-165:~/workspace/test/test1$ aarch64-linux-android-objdump -D main.o
main.o: file format elf64-littleaarch64
Disassembly of section .text:
0000000000000000 <main>:
0: d10043ff sub sp, sp, #0x10
4: 52801900 mov w0, #0xc8 // #200
8: b9000fe0 str w0, [sp,#12]
c: 90000000 adrp x0, 4 <main+0x4>
10: f9400000 ldr x0, [x0]
14: 52800c81 mov w1, #0x64 // #100
18: b9000001 str w1, [x0]
1c: 90000000 adrp x0, 4 <main+0x4>
20: f9400000 ldr x0, [x0]
24: b9400000 ldr w0, [x0]
28: b9400fe1 ldr w1, [sp,#12]
2c: 0b000020 add w0, w1, w0
30: b9000fe0 str w0, [sp,#12]
34: 52800000 mov w0, #0x0 // #0
38: 910043ff add sp, sp, #0x10
3c: d65f03c0 ret
Disassembly of section .comment:
0000000000000000 <.comment>:
0: 43434700 .inst 0x43434700 ; undefined
4: 4728203a .inst 0x4728203a ; undefined
8: 2029554e .inst 0x2029554e ; undefined
c: 2e392e34 uqsub v20.8b, v17.8b, v25.8b
10: 30322078 adr x24, 6441d <main+0x6441d>
14: 31303531 adds w17, w9, #0xc0d
18: 28203332 stnp w18, w12, [x25,#-256]
1c: 72657270 .inst 0x72657270 ; undefined
20: 61656c65 .inst 0x61656c65 ; undefined
24: 00296573 .inst 0x00296573 ; NYI
（4）、
//static int x;
//static int y = 10;
//int z;
int w = 20;
int main()
{
int s = 200;
// x = 100;
// s=s+x;
// s=s+y;
// z=100;
// s=s+z;
s=s+w;
return 0;
}
hehezhou@buildsrv-165:~/workspace/test/test1$ aarch64-linux-android-gcc-4.9 -c main.c
Android GCC has been deprecated in favor of Clang, and will be removed from
Android in 2020-01 as per the deprecation plan in:
https://android.googlesource.com/platform/prebuilts/clang/host/linux-x86/+/master/GCC_4_9_DEPRECATION.md
hehezhou@buildsrv-165:~/workspace/test/test1$ aarch64-linux-android-objdump -D main.o
main.o: file format elf64-littleaarch64
Disassembly of section .text:
0000000000000000 <main>:
0: d10043ff sub sp, sp, #0x10
4: 52801900 mov w0, #0xc8 // #200
8: b9000fe0 str w0, [sp,#12]
c: 90000000 adrp x0, 0 <main>
10: f9400000 ldr x0, [x0]
14: b9400000 ldr w0, [x0]
18: b9400fe1 ldr w1, [sp,#12]
1c: 0b000020 add w0, w1, w0
20: b9000fe0 str w0, [sp,#12]
24: 52800000 mov w0, #0x0 // #0
28: 910043ff add sp, sp, #0x10
2c: d65f03c0 ret
Disassembly of section .data:
0000000000000000 <w>:
0: 00000014 .word 0x00000014
Disassembly of section .comment:
0000000000000000 <.comment>:
0: 43434700 .inst 0x43434700 ; undefined
4: 4728203a .inst 0x4728203a ; undefined
8: 2029554e .inst 0x2029554e ; undefined
c: 2e392e34 uqsub v20.8b, v17.8b, v25.8b
10: 30322078 adr x24, 6441d <main+0x6441d>
14: 31303531 adds w17, w9, #0xc0d
18: 28203332 stnp w18, w12, [x25,#-256]
1c: 72657270 .inst 0x72657270 ; undefined
20: 61656c65 .inst 0x61656c65 ; undefined
24: 00296573 .inst 0x00296573 ; NYI
（5）
static int x;
static int y = 10;
int z;
int w = 20;
int main()
{
int s = 200;
x = 100;
s=s+x;
s=s+y;
z=100;
s=s+z;
s=s+w;
return 0;
}
hehezhou@buildsrv-165:~/workspace/test/test1$ aarch64-linux-android-objdump -D main.o
main.o: file format elf64-littleaarch64
Disassembly of section .text:
0000000000000000 <main>:
0: d10043ff sub sp, sp, #0x10
4: 52801900 mov w0, #0xc8 // #200
8: b9000fe0 str w0, [sp,#12]
c: 90000000 adrp x0, 0 <main>
10: 91000000 add x0, x0, #0x0
14: 52800c81 mov w1, #0x64 // #100
18: b9000001 str w1, [x0]
1c: 90000000 adrp x0, 0 <main>
20: 91000000 add x0, x0, #0x0
24: b9400000 ldr w0, [x0]
28: b9400fe1 ldr w1, [sp,#12]
2c: 0b000020 add w0, w1, w0
30: b9000fe0 str w0, [sp,#12]
34: 90000000 adrp x0, 0 <main>
38: 91000000 add x0, x0, #0x0
3c: b9400000 ldr w0, [x0]
40: b9400fe1 ldr w1, [sp,#12]
44: 0b000020 add w0, w1, w0
48: b9000fe0 str w0, [sp,#12]
4c: 90000000 adrp x0, 4 <main+0x4>
50: f9400000 ldr x0, [x0]
54: 52800c81 mov w1, #0x64 // #100
58: b9000001 str w1, [x0]
5c: 90000000 adrp x0, 4 <main+0x4>
60: f9400000 ldr x0, [x0]
64: b9400000 ldr w0, [x0]
68: b9400fe1 ldr w1, [sp,#12]
6c: 0b000020 add w0, w1, w0
70: b9000fe0 str w0, [sp,#12]
74: 90000000 adrp x0, 4 <main+0x4>
78: f9400000 ldr x0, [x0]
7c: b9400000 ldr w0, [x0]
80: b9400fe1 ldr w1, [sp,#12]
84: 0b000020 add w0, w1, w0
88: b9000fe0 str w0, [sp,#12]
8c: 52800000 mov w0, #0x0 // #0
90: 910043ff add sp, sp, #0x10
94: d65f03c0 ret
Disassembly of section .data:
0000000000000000 <y>:
0: 0000000a .word 0x0000000a
0000000000000004 <w>:
4: 00000014 .word 0x00000014
Disassembly of section .bss:
0000000000000000 <x>:
0: 00000000 .word 0x00000000
Disassembly of section .comment:
0000000000000000 <.comment>:
0: 43434700 .inst 0x43434700 ; undefined
4: 4728203a .inst 0x4728203a ; undefined
8: 2029554e .inst 0x2029554e ; undefined
c: 2e392e34 uqsub v20.8b, v17.8b, v25.8b
10: 30322078 adr x24, 6441d <w+0x64419>
14: 31303531 adds w17, w9, #0xc0d
18: 28203332 stnp w18, w12, [x25,#-256]
1c: 72657270 .inst 0x72657270 ; undefined
20: 61656c65 .inst 0x61656c65 ; undefined
24: 00296573 .inst 0x00296573 ; NYI
标签：assembly,undefined,int,sp,C语言,inst,w0,x0,ARM 来源： https://blog.51cto.com/u_15278218/2930976