[GAS] Dynamic memory allocation - Other

GT3X

In asm u can allocate the memory dynamc with the syscall mmap. With the following code a memoryrange gets allocated during the runtime. The startadress is in the %eax register. So nothing special


&#46;data
&#46;comm mmap_, 24
&#46;text 
&#46;macro alloc length

#prepare params for mmap
movl $0, mmap_ # 0- Startadress gets selected from Kernel 
movl \length, mmap_+4 #size of Adressrange
movl $3, mmap_+8 #PROT_WITE / PROT_READ 0x02, 0x01
movl $34, mmap_+12 #map anonymously (0x20), map_private(0x20)
movl $-1, mmap_+16 #fd -1 portability 
movl $0, mmap_+20 # offset ignored

#allocate memory
movl $90, %eax
leal mmap_ , %ebx
int $0x80
&#46;endm

too release it


&#46;macro free address length
movl $91, %eax
movl \address, %ebx
movl \length, %ecx
int $0x80
&#46;endm

Xin

Good job keep it up

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