94 lines
2.1 KiB
NASM
94 lines
2.1 KiB
NASM
;
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; Written by the Chair for Operating Systems, RWTH Aachen University
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;
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; NO Copyright (C) 2010-2011, Stefan Lankes
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; consider these trivial functions to be public domain.
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;
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; These functions are distributed on an "AS IS" BASIS,
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; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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;
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[BITS 32]
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SECTION .text
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global strcpy
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strcpy:
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push ebp
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mov ebp, esp
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push edi
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push esi
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mov esi, [ebp+12]
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mov edi, [ebp+8]
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L1:
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lodsb
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stosb
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test al, al
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jne L1
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mov eax, [ebp+8]
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pop esi
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pop edi
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pop ebp
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ret
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global strncpy
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strncpy:
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push ebp
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mov ebp, esp
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push edi
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push esi
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mov ecx, [ebp+16]
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mov esi, [ebp+12]
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mov edi, [ebp+8]
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L2:
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dec ecx
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js L3
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lodsb
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stosb
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test al, al
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jne L1
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rep
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stosb
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L3:
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mov eax, [ebp+8]
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pop esi
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pop edi
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pop ebp
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ret
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; The following function is derived from JamesM's kernel development tutorials
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; (http://www.jamesmolloy.co.uk/tutorial_html/)
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global copy_page_physical
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copy_page_physical:
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push esi ; According to __cdecl, we must preserve the contents of ESI
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push edi ; and EDI.
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pushf ; push EFLAGS, so we can pop it and reenable interrupts
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; later, if they were enabled anyway.
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cli ; Disable interrupts, so we aren't interrupted.
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; Load these in BEFORE we disable paging!
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mov edi, [esp+12+4] ; Destination address
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mov esi, [esp+12+8] ; Source address
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mov edx, cr0 ; Get the control register...
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and edx, 0x7fffffff ; and...
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mov cr0, edx ; Disable paging.
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cld
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mov ecx, 0x400 ; 1024*4bytes = 4096 bytes = page size
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rep movsd ; copy page
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mov edx, cr0 ; Get the control register again
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or edx, 0x80000000 ; and...
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mov cr0, edx ; Enable paging.
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popf ; Pop EFLAGS back.
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pop edi ; Get the original value of EDI
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pop esi ; and ESI back.
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ret
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SECTION .note.GNU-stack noalloc noexec nowrite progbits
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