帮忙写一个微机汇编程序，从键盘输入一个字符串，以＄字符为结束标志，字符串长度小于255。编程统计？

ASSUME CS:SEG2, DS: SEG1 SEG1 SEGMENT STR DB 'SDrtgDrtg43%&UHcvb <>m<>fhdgDF', 36 LEN EQU $ - STR DB 13, 10 NEW_STR DB LEN DUP (?) NUM DW 0 SEG1 ENDS SEG2 SEGMENT START: MOV BX, SEG1 MOV DS, BX;-------------------- MOV AH, 9 LEA DX, STR INT 21H LEA SI, STR LEA DI, NEW_STRLP: MOV AL, [SI] INC SI CMP AL, 36 JZ EXIT OR AL, 20H CMP AL, 'a' JB LP CMP AL, 'z' JA LP MOV [DI], AL INC DI INC NUM JMP LP ;--------------------EXIT: LEA DI, NEW_STR - 2 MOV AH, 2 MOV CX, NUM ADD CX, 2LP1: MOV DL, [DI] INT 21H INC DI LOOP LP1 MOV AH, 4CH INT 21H;-------------------- SEG2 ENDS END START