Compact implementation of logical AND in x86 assembly

Question

Hi, x86 assembler geeks!

I have an interesting problem to test your assembler programming skills.
I'm the author of this problem, so I know the correct answer.

Your task is to implement logical AND in x86 assembly and satisfy the following 5 conditions:

Condition #1
Boolean values are encoded in 16-bit words in the most standard way:

0x0000         = False
0x0001..0xFFFF = True

Condition #2
Operation "logical AND" for 16-bit values looks like the following:

  logical_AND(value1,value2) == 0    if (value1 == 0) or (value2 == 0)
  logical_AND(value1,value2) != 0    if (value1 != 0) and (value2 != 0)

You must give correct result for any 16-bit value1 and value2.
Please note that you are free to choose any nonzero value for "True" result, not only 0x0001 or 0xFFFF.
For example, it is allowed to have logical_AND(0xDEAD,0xBEEF) == 42

Condition #3
You should write 16-bit code for x86 real mode.
Input parameters are in AX and BX, result is in AX:

  ; Registers on entry:
  ;  AX = value1
  ;  BX = value2
  (your code goes here)
  ; Registers on exit:
  ;  AX = logical_AND(value1,value2)
  ;  BX,CX,DX,SI,DI,BP and their 32-bit extensions may contain garbage on exit

Obviously, single instruction and AX,BX is not enough: when AX=1 and BX=2, result must be nonzero.

Condition #4
Any x86 instructions are allowed (even SSE).
You can use the stack.
Neither external code (call ExternalProc, int XX) nor external lookup tables are permitted.
All initialized data should be inside your chunk of code.

Example solution (12 bytes of code)

   ; **** Entry: AX, BX
   test AX,AX
   setnz AL
   test BX,BX
   setnz BL
   and AX,BX
   ; **** Exit: AX

Example solution (6 bytes of code)

   ; **** Entry: AX, BX
   neg AX
   sbb AX,AX
   and AX,BX
   ; **** Exit: AX

Example solution (5 bytes of code)

   ; **** Entry: AX, BX
   cmp AX,BX
   jb @Done
   xchg AX,BX
@Done:
   ; **** Exit: AX

Condition #5
You must perform the task using only 4 bytes of code.

Probably, you have already found very short solution with input parameters in AX and CX.
Nice try!
Unfortunately, this solution is not a correct answer (because of using CX as input).

Probably, there are more than one correct answer exist.
Anyway, first correct answer (which satisfies all 5 requirements) will be awarded 500 rep points bounty.

My own 4-byte-long code is quite unexpected and has very remarkable property.

Please do not brute-force. Use your brains.

To moderators:
This is not a code-golf. First correct answer will be accepted.

Answer 1

 MUL BX 
 OR  AX, DX

On older machines this might not be very fast compared to longer answers.