nand bitwise operation in MIPS Assembly

I've been trying to figure out how to do a nand bitwise operation in assembly but have been unsuccessful. I'm tried to write a logic gate simulator that will essentially produce this truth table for inputs A and B

   A  |   B  ||  F
  -----------------
   lo |  lo  ||  hi
   lo |  hi  ||  hi
   hi |  lo  ||  hi
   hi |  hi  ||  lo

I've tried ever开发者_如何学JAVAything.

  and  $t3,$t1,$t  
  not  $t4,$t3

Does not produce the correct output

OF course it does, look at the truth table:

A    B    And   Nand
---------------------
lo   lo   lo    hi
lo   hi   lo    hi
hi   lo   lo    hi
hi   hi   hi    lo

As you can see, you can get nand values by negating previously anded values. But you may have forgotten that and and not operate on each bit of the registers. I think you confused with boolean values, where (usually) any non-zero value is assumed to be true. Therefore,

   11101001 nand 01000111 = 
 = ~ (11101001 and 01000111) =
 = ~ 01000001 = 
 = 10111110

because

1 and 0 = 0
1 and 1 = 1
1 and 0 = 0
0 and 0 = 0
1 and 0 = 0
0 and 1 = 0
0 and 1 = 0
1 and 1 = 1

Next time you should post both expected and actual results too, this way it is easier for us to understand what went wrong.