Diassemblieren
Aus C und Assembler mit Raspberry
Diassemblieren
-> objdump -s -d HelloWorld.o > HelloWorld.diassem
Hello.o: file format elf64-littleaarch64
Contents of section .text:
0000 200080d2 e1000058 a20180d2 080880d2 ......X........ 0010 010000d4 000080d2 a80b80d2 010000d4 ................ 0020 00000000 00000000 ........
Contents of section .data:
0000 48656c6c 6f20576f 726c6421 0a Hello World!.
Disassembly of section .text:
0000000000000000 <_start>:
0: d2800020 mov x0, #0x1 // #1 4: 580000e1 ldr x1, 20 <_start+0x20> 8: d28001a2 mov x2, #0xd // #13 c: d2800808 mov x8, #0x40 // #64 10: d4000001 svc #0x0 14: d2800000 mov x0, #0x0 // #0 18: d2800ba8 mov x8, #0x5d // #93 1c: d4000001 svc #0x0
...
negative Zahlen
-> Beispiel: 5 + -3
3 in 1 byte is 0x03 or 0000 0011. Inverting the bits is 1111 1100 Add 1 to get 1111 1101 = 0xFD Now add 5 + 0xFD = 0x102 = 2
movadd.o: file format elf64-littleaarch64
Contents of section .text:
0000 001980d2 812580d2 0200018b a00080d2 .....%.......... 0010 41008092 0200018b 000080d2 a80b80d2 A............... 0020 010000d4 ....
Disassembly of section .text:
0000000000000000 <_start>:
0: d2801900 mov x0, #0xc8 // #200 4: d2802581 mov x1, #0x12c // #300 8: 8b010002 add x2, x0, x1 c: d28000a0 mov x0, #0x5 // #5 10: 92800041 mov x1, #0xfffffffffffffffd // #-3 14: 8b010002 add x2, x0, x1 18: d2800000 mov x0, #0x0 // #0 1c: d2800ba8 mov x8, #0x5d // #93 20: d4000001 svc #0x0
