Board.KolibriOS.org

Code: Select all

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szAllZero      db "All Zero",0
szSomeNotZero  db "Some Not Zero",0
Result dd szAllZero
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SECTION .bss
MemoryBuffer resb 1024 * 1024 * 1024
.end:
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        mov    edi, MemoryBuffer
        mov    ecx, MemoryBuffer.end - MemoryBuffer
        xor    eax, eax
        repe   scasb
        je     .ok
        mov    Dword [Result], szSomeNotZero
.ok:
        push   Dword [Result]
        call   [con_write_asciiz]        
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Code: Select all

f68:
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.12:
        stdcall user_alloc, ecx
        mov     [esp+SYSCALL_STACK._eax], eax
        ret
..............................................                
proc user_alloc stdcall, alloc_size:dword
        push    ebx esi edi
        mov     ebx, [current_process]
        lea     ecx, [ebx+PROC.heap_lock]
        call    mutex_lock
        mov     ecx, [alloc_size]
        add     ecx, (4095+PAGE_SIZE)
        and     ecx, not 4095
        mov     esi, dword [ebx+PROC.heap_base] ; heap_base
        mov     edi, dword [ebx+PROC.heap_top]  ; heap_top
.scan:
        cmp     esi, edi
        jae     .m_exit

        mov     ebx, esi
        shr     ebx, 12
        mov     eax, [page_tabs+ebx*4]
        test    al, FREE_BLOCK
        jz      .test_used
        and     eax, 0xFFFFF000
        cmp     eax, ecx   ;alloc_size
        jb      .m_next
        jz      @f

        lea     edx, [esi+ecx]
        sub     eax, ecx
        or      al, FREE_BLOCK
        shr     edx, 12
        mov     [page_tabs+edx*4], eax
@@:
        or      ecx, USED_BLOCK
        mov     [page_tabs+ebx*4], ecx
        shr     ecx, 12
        inc     ebx
        dec     ecx
        jz      .no
@@:
        mov     dword [page_tabs+ebx*4], 2
        inc     ebx
        dec     ecx
        jnz     @B
.no:

        mov     edx, [current_process]
        mov     ebx, [alloc_size]
        add     ebx, 0xFFF
        and     ebx, not 0xFFF
        add     [edx+PROC.mem_used], ebx

        lea     ecx, [edx+PROC.heap_lock]
        call    mutex_unlock

        lea     eax, [esi+4096]

        pop     edi
        pop     esi
        pop     ebx
        ret
.test_used:
        test    al, USED_BLOCK
        jz      .m_exit

        and     eax, 0xFFFFF000
.m_next:
        add     esi, eax
        jmp     .scan
.m_exit:
        mov     ecx, [current_process]
        lea     ecx, [ecx+PROC.heap_lock]
        call    mutex_unlock

        xor     eax, eax
        pop     edi
        pop     esi
        pop     ebx
        ret
endp