4. Specifying Operand Size

• You must give the size of an indirect memory operand in one of three ways:

  • By the variable's declared size

  • With the PTR operator (which acts similar to C-style cast)

  • Implied by the size of the other operand.

• The following lines illustrate all three methods, assuming the size of the table array is WORD, as declared earlier.

          table   WORD    100 DUP (0)
          .
          .
          .
          mov     table[bx], 0      ; 2 bytes - from size of table
          mov     BYTE PTR table, 0 ; 1 byte  - specified by BYTE
          mov     ax, [bx]          ; 2 bytes - implied by AX