


It is a multiple of two. Such addresses have a zero in the low-order bit.

Storing Halfwords

Only one store halfword instruction is needed. The low-order two bytes of the designated register are copied to memory, no matter what the upper two bytes are. Of course, the register is not changed when its data is copied to memory.

sh    t,off(b)    # Halfword at off+b <— low-order 
                  # two bytes from $t.
                  # b is a base register. 
                  # off is 16-bit two's complement.

MIPS arithmetic instructions that use registers always use full registers, regardless of how data was loaded into the register. For example, an addu instruction does a full 32-bit addition even if one of the operand registers was loaded with lh (or lb).


Perform these two addition problems:

 0110 1110         0000 0000 0000 0000 0000 0000 0110 1110
 1100 0110         0000 0000 0000 0000 0000 0000 1100 0110