HELP!

Hi, I'm trying to link an assembly procedure to my C++ project, I'm using Visual C++ 2005.

I'm getting an error:
DecodeB64.obj : error LNK2019: unresolved external symbol _Base64_Decode referenced in function _main
I added both the .asm and the .cpp files to my project.
In my cpp file:

Code:
#define	DWORD	unsigned int

extern "C" DWORD Base64_Decode(char *, DWORD, char *);
and in main:

Code:
dwDataLen = Base64_Decode(cpInputBuffer, dwFileSize, cpOutputBuffer);
my .asm file:

Code:
public _Base64_Decode
.386
.MODEL    flat, stdcall

.CODE

_Base64_Decode    proc

	local  InputLen : dword
	local  InputBuf : dword
	local  OutputBuf : dword

	pop    InputBuf
	pop    InputLen
	pop    OutputBuf

	pushad
	
	mov    ecx,InputLen
	mov    esi,InputBuf

	ASCII_TO_B64_LOOP:

		mov    ah,[esi]
		cmp    ah,61h    ;compare to 'a'
		jl     CMP_CAPS
		sub    ah,47h
		jmp    NEXT
	    
		CMP_CAPS:
		cmp    ah,41h    ;compare to 'A'
		jl     CMP_PAD
		sub    ah,41h
		jmp    NEXT
	    
		CMP_PAD:
		cmp    ah,3D     ;compare to '='
		jne    CMP_NUMERAL
		mov    ah,0h
		jmp    NEXT
	    
		CMP_NUMERAL:
		cmp    ah,30h    ;compare to '0'
		jl     SYMBOL
		add    ah,4h
		jmp    NEXT
	    
		SYMBOL:
		cmp    ah,2Fh    ;compare to '/'
		jl     PLUS
		mov    ah,3Fh
		jmp    NEXT
	    
		PLUS:            ;it's '+'     
		mov    ah,3Eh
		jmp    NEXT
	    
		NEXT:
		inc    esi
	                  
	loopw  ASCII_TO_B64_LOOP

	mov    edi,OutputBuf
	mov    esi,InputBuf
	mov    ecx,InputLen
	xor    edx,edx
	mov    eax,4h
	div    ecx
	mov    ecx,eax

	DECODING_LOOP:

		mov    ah,[esi]
		mov    al,[esi+1]
		shl    al,2
		mov    bl,ah
		mov    dh,al
		shld   bx,dx,2
		mov    ah,bl
		mov    [edi],ah
		inc    edi
		inc    esi
	    
		mov    ah,[esi]
		mov    al,[esi+1]
		shl    al,2
		mov    bl,ah
		mov    dh,al
		shld   bx,dx,4
		mov    ah,bl
		mov    [edi],ah
		inc    edi
		inc    esi

		mov    ah,[esi]
		mov    al,[esi+1]
		shl    al,2
		mov    bl,ah
		mov    dh,al
		shld   bx,dx,6
		mov    ah,bl
		mov    [edi],ah
		inc    edi
		inc    esi

		inc    esi

	loopd  DECODING_LOOP

	popad
	
	mov    dx,0h
	mov    ax,sizeof OutputBuf

	ret

_Base64_Decode  endp

end