求教这段程序的功能

ADDB SP,#2

MOVL DP,#0X09

MOVL @0X010,XAR4

MOVL XAR6,@0X10

CLRC SXM

CMPL ACC,XAR6

SB 38,LOS

MOVL XAR4,@0X10

MOV AL,*+XAR4[0]

MOV *-SP[1],AL

MOVL XAR4,@0X10

MOV *+XAR4[0],#0XAAAA

MOVL XAR4,@0x10

CMP *+XAR4[0],#0XAAAA

SBF 3,EQ