汇编循环问题。。。。。

DATA SEGMENT
    BBUF DB 86H,38H    ;char bbuf[] = {0x86, 0x38};
    LENGTH1 EQU $-BBUF ;#define LENGTH1 (sizeof(bbuf));
    ABUF DB 4 DUP(0)   ;char abuf[4];
DATA ENDS
STACK1 SEGMENT PARA STACK
      DW 20H DUP(0)
STACK1 ENDS
CODE SEGMENT
    ASSUME CS:CODE,DS:DATA,SS:STACK1
START:
    MOV AX,DATA
    MOV DS,AX
    MOV SI,0           ;short i = 0;
    MOV DI,0           ;short j = 0;
    MOV CX,LENGTH1     ;short count = LENGTH1;
LOP:
    MOV AL,BBUF[SI]    ;char ch = bbuf[i];
    MOV BL,AL
    MOV CL,4           ;LOBYTE(count) = 4;
    SHR BL,CL
    ADD BL,30H
    MOV ABUF[DI],BL    ;abuf[j] = (ch >> LOBYTE(count) + 0x30);
    AND AL,0FH         ;ch &= 0x0f
    ADD AL,30H         ;ch += 0x30;
    MOV ABUF[DI+1],AL  ;abuf[j+1] =  ch;
NEXT:
    INC SI             ;i++;
    INC DI
    INC DI             ;j += 2;
    LOOP LOP           ;while(--count);
    MOV AH,4CH
    INT 21H            ;exit(0);
CODE ENDS
    END START