83 lines
1.8 KiB
Text
83 lines
1.8 KiB
Text
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alloc(TypeName,256)
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alloc(ByteSize,4)
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alloc(ConvertRoutine,1024)
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alloc(ConvertBackRoutine,1024)
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TypeName:
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db '2 Byte Big Endian',0
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ByteSize:
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dd 2
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//The convert routine should hold a routine that converts the data to an integer (in eax)
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//function declared as: stdcall int ConvertRoutine(unsigned char *input);
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//Note: Keep in mind that this routine can be called by multiple threads at the same time.
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ConvertRoutine:
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//jmp dllname.functionname
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[64-bit]
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//or manual:
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//parameters: (64-bit)
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//rcx=address of input
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xor eax,eax
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mov ax,[rcx] //eax now contains the bytes 'input' pointed to
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xchg ah,al //convert to big endian
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ret
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[/64-bit]
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[32-bit]
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//jmp dllname.functionname
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//or manual:
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//parameters: (32-bit)
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push ebp
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mov ebp,esp
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//[ebp+8]=input
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//example:
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mov eax,[ebp+8] //place the address that contains the bytes into eax
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mov ax,[eax] //place the bytes into eax so it's handled as a normal 4 byte value
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and eax,ffff //cleanup
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xchg ah,al //convert to big endian
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pop ebp
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ret 4
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[/32-bit]
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//The convert back routine should hold a routine that converts the given integer back to a row of bytes (e.g when the user wats to write a new value)
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//function declared as: stdcall void ConvertBackRoutine(int i, unsigned char *output);
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ConvertBackRoutine:
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//jmp dllname.functionname
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//or manual:
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[64-bit]
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//parameters: (64-bit)
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//ecx=input
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//rdx=address of output
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//example:
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xchg ch,cl //convert the little endian input into a big endian input
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mov [rdx],cx //place the integer the 4 bytes pointed to by rdx
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ret
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[/64-bit]
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[32-bit]
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//parameters: (32-bit)
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push ebp
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mov ebp,esp
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//[ebp+8]=input
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//[ebp+c]=address of output
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//example:
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push eax
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push ebx
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mov eax,[ebp+8] //load the value into eax
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mov ebx,[ebp+c] //load the address into ebx
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//convert the value to big endian
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xchg ah,al
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mov [ebx],ax //write the value into the address
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pop ebx
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pop eax
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pop ebp
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ret 8
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[/32-bit]
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