DB 0DH,0AH,24H ；这个24H有没有什么特殊含义？

lizhuohua 2003-08-10 09:58:51

DB 0DH,0AH,24H ；这个24H有没有什么特殊含义？
0DH，0AH是回车和换行，这个24H有没有什么特殊含义？

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zhaobird 2003-08-11

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DB 0DH,0AH,24H ；这个24H有没有什么特殊含义？
相当于DB 0DH,0AH,'$' ；是作为结束符的，比如在屏幕输出一个字符串，用int 21的9好功能但要求是以'$'结束的字符串。
int 21,9
INT 21,9 - Print String

AH = 09
DS:DX = pointer to string ending in "$"

iceheart 2003-08-10

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'$'，DOS21H中断字符串操作中串的结束标志，C中应该是'\0'

www.dslcd.com www.dslcd.com COM EQU 20H;ZHI LIN JI CONG QI DAT EQU 21H;SHU JU JI CONG QI CS2 EQU P3.3; CS1 EQU P3.2;www.dslcd.com SID EQU P3.1;SHU JU XIAN SCLK EQU P3.0;SHI ZHONG XIANG ORG 0000H;www.dslcd.com AJMP MAIN; ORG 0013H; AJMP INSER;www.dslcd.com ORG 0030H; MAIN:MOV SP,#60H; CLR IT1; SETB PX1; SETB EX1; SETB EA; LCALL INT; LCALL CG_WRITE1; MOV DPTR,#TABDY3; ACALL YS;www.dslcd.com LCALL DEL; MOV DPTR,#TABDY0;www.dslcd.com ACALL YS; LCALL DEL;www.dslcd.com MOV DPTR,#TABDY1; ACALL YS; LCALL DEL; MOV DPTR,#TABDY2; ACALL YS;www.dslcd.com LCALL DEL; MOV DPTR,#TABDY4; ACALL YS; LCALL DEL; MOV DPTR,#TABDY5; ACALL YS; LCALL DEL; LCALL CG_WRITE; MOV DPTR,#TABDY2; ACALL YS; LCALL DEL; MOV DPTR,#TABDY3; ACALL YS; LCALL DEL; MOV DPTR,#TABDY4; ACALL YS; LCALL DEL; MOV DPTR,#TABDY5; ACALL YS; LCALL DEL;www.dslcd.com AJMP MAIN; PR1:PUSH ACC; MOV A,COM; SETB CS1;xie ru zwww.dslcd.comhi ling SETB CS2; SETB SID; CLR SCLK; SETB SCLK;1 CLR SCLK; SETB SCLK;2 CLR SCLK; SETB SCLK;3 CLR SCLK; SETB SCLK;4www.dslcd.com CLR SCLK; SETB SCLK;5 CLR SCLK; CLR SID; SETB SCLK;1 CLR SCLK; SETB SCLK;2 CLR SCLK; SETB SCLK;3 CLR SCLK; MOV C,ACC.7; MOV SID,C; SETB SCLK; CLR SCLK; MOV C,ACC.6; MOV SID,C; SETB SCLK; CLR SCLK; MOV C,ACC.5; MOV SID,C; SETB SCLK; CLR SCLK; MOV C,ACC.4; MOV SID,C; SETB SCLK; CLR SCLK; CLR SID; SETB SCLK;1 CLR SCLK; SETB SCLK;2 CLR SCLK; SETB SCLK;3 CLR SCLK; SETB SCLK;4 CLR SCLK; MOV C,ACC.3; MOV SID,C; SETB SCLK; CLR SCLK; MOV C,ACC.2; MOV SID,C; SETB SCLK; CLR SCLK; MOV C,ACC.1; MOV SID,C; SETB SCLK; CLR SCLK; MOV C,ACC.0; MOV SID,C;www.dslcd.com SETB SCLK; CLR SCLK; CLR SID; SETB SCLK;1 CLR SCLK; SETB SCLK;2 CLR SCLK; SETB SCLK;3 CLR SCLK; SETB SCLK;4 CLR SCLK; CLR CS1; CLR CS2; ACALL DLY8; POP ACC; RET; PR2:PUSH ACC;XIE RU SHU JU MOV A,DAT;www.dslcd.com SETB CS1; SETB CS2; SETB SID; CLR SCLK; SETB SCLK;1 CLR SCLK; SETB SCLK;2 CLR SCLK; SETB SCLK;3 CLR SCLK; SETB SCLK;4 CLR SCLK; SETB SCLK;5 CLR SCLK; CLR SID; SETB SCLK;1 CLR SCLK; SETB SID;www.dslcd.comwww.dslcd.com SETB SCLK;2 CLR SCLK; CLR SID; SETB SCLK;3 CLR SCLK; MOV C,ACC.7; MOV SID,C; SETB SCLK; CLR SCLK; MOV C,ACC.6;www.dslcd.com MOV SID,C; SETB SCLK; CLR SCLK; MOV C,ACC.5; MOV SID,C; SETB SCLK; CLR SCLK; MOV C,ACC.4; MOV SID,C; SETB SCLK; CLR SCLK; CLR SID; SETB SCLK;1 CLR SCLK; SETB SCLK;2 CLR SCLK; SETB SCLK;3 CLR SCLK; SETB SCLK;4 CLR SCLK; MOV C,ACC.3; MOV SID,C; SETB SCLK; CLR SCLK;www.dslcd.comwww.dslcd.com MOV C,ACC.2; MOV SID,C; SETB SCLK; CLR SCLK; MOV C,ACC.1; MOV SID,C; SETB SCLK; CLR SCLK; MOV C,ACC.0; MOV SID,C;www.dslcd.com SETB SCLK; CLR SCLK; CLR SID; SETB SCLK;1 CLR SCLK; SETB SCLK;2 CLR SCLK; SETB SCLK;3 CLR SCLK; SETB SCLK;4 CLR SCLK; CLR CS1; CLR CS2; ACALL DELAY; POP ACC; RET; INSER:ACALL DELAY;ZHONG DUAN JNB P3.3,$;www.dslcd.com ACALL DELAY; JB P3.3,$; ACALL DELAY; JNB P3.3,$; ACALL DELAY; JNB P3.3,$; RETI; YS:MOV COM,#80H; LCALL PR1; MOV R2,#32; MOV R3,#00H; LOOP1:MOV A,R3; MOVC A,@A+DPTR; MOV DAT,A; LCALL PR2; INC R3; DJNZ R2,LOOP1; MOV COM,#90H; LCALL PR1; MOV R2,#32; LOOP2:MOV A,R3; MOVC A,@A+DPTR; MOV DAT,A; LCALL PR2;www.dslcd.com INC R3; DJNZ R2,LOOP2; RET; INT:MOV COM,#38H; LCALL PR1; MOV COM,#01H; LCALL PR1; MOV COM,#06H; LCALL PR1; MOV COM,#0FH; LCALL PR1; RET; CG_WRITE:MOV COM,#40H; LCALL PR1; MOV R2,#128; MOV R3,#00H; MOV DPTR,#CGTAB1; CG1:MOV A,R3; MOVC A,@A+DPTR; MOV DAT,A; LCALL PR2; INC R3; DJNZ R2,CG1; RET; CG_WRITE1:MOV COM,#40H; LCALL PR1; MOV R2,#128; MOV R3,#00H; MOV DPTR,#CGTAB; CG2:MOV A,R3; MOVC A,@A+DPTR; MOV DAT,A; LCALL PR2; INC R3; DJNZ R2,CG2; RET; CGTAB:DB 00H,00H,00H,00H,00H,00H,00H,00H;0 DB 00H,00H,00H,00H,00H,00H,00H,00H; DB 00H,00H,00H,00H,00H,00H,00H,00H; DB 00H,00H,00H,00H,00H,00H,00H,00H; DB 0FFH,0FFH,0FFH,0FFH,0FFH,0FFH,0FFH,0FFH;1 DB 0FFH,0FFH,0FFH,0FFH,0FFH,0FFH,0FFH,0FFH; DB 0FFH,0FFH,0FFH,0FFH,0FFH,0FFH,0FFH,0FFH; DB 0FFH,0FFH,0FFH,0FFH,0FFH,0FFH,0FFH,0FFH; DB 0AAH,0AAH,055H,055H,0AAH,0AAH,055H,055H;2 DB 0AAH,0AAH,055H,055H,0AAH,0AAH,055H,055H; DB 0AAH,0AAH,055H,055H,0AAH,0AAH,055H,055H; DB 0AAH,0AAH,055H,055H,0AAH,0AAH,055H,055H; DB 055H,055H,0AAH,0AAH,055H,055H,0AAH,0AAH;3 DB 055H,055H,0AAH,0AAH,055H,055H,0AAH,0AAH; DB 055H,055H,0AAH,0AAH,055H,055H,0AAH,0AAH; DB 055H,055H,0AAH,0AAH,055H,055H,0AAH,0AAH; CGTAB1:DB 055H,055H,055H,055H,055H,055H,055H,055H;0 DB 055H,055H,055H,055H,055H,055H,055H,055H; DB 055H,055H,055H,055H,055H,055H,055H,055H; DB 055H,055H,055H,055H,055H,055H,055H,055H; DB 0AAH,0AAH,0AAH,0AAH,0AAH,0AAH,0AAH,0AAH;1 DB 0AAH,0AAH,0AAH,0AAH,0AAH,0AAH,0AAH,0AAH; DB 0AAH,0AAH,0AAH,0AAH,0AAH,0AAH,0AAH,0AAH; DB 0AAH,0AAH,0AAH,0AAH,0AAH,0AAH,0AAH,0AAH; DB 0FFH,0FFH,000H,000H,0FFH,0FFH,000H,000H;2 DB 0FFH,0FFH,000H,000H,0FFH,0FFH,000H,000H; DB 0FFH,0FFH,000H,000H,0FFH,0FFH,000H,000H; DB 0FFH,0FFH,000H,000H,0FFH,0FFH,000H,000H; DB 000H,000H,0FFH,0FFH,000H,000H,0FFH,0FFH;3 DB 000H,000H,0FFH,0FFH,000H,000H,0FFH,0FFH; DB 000H,000H,0FFH,0FFH,000H,000H,0FFH,0FFH; DB 000H,000H,0FFH,0FFH,000H,000H,0FFH,0FFH; TABDY0:DB 0BBH,0B6H,0D3H,0ADH,0BBH,0DDH,0B9H,0CBH,0D4H,0A3H,0CCH,0EFH,0B5H,0E7H,0D7H,0D3H,0B9H,0ABH,0CBH,0BEH; DB 0BBH,0B6H,0D3H,0ADH,0BBH,0DDH,0B9H,0CBH,0D4H,0A3H,0CCH,0EFH; DB 0BBH,0B6H,0D3H,0ADH,0BBH,0DDH,0B9H,0CBH,0D4H,0A3H,0CCH,0EFH,0B5H,0E7H,0D7H,0D3H,0B9H,0ABH,0CBH,0BEH; DB 0BBH,0B6H,0D3H,0ADH,0BBH,0DDH,0B9H,0CBH,0D4H,0A3H,0CCH,0EFH; TABDY1:DB 21H,22H,23H,24H,25H,26H,27H,28H,29H,2AH,2BH,2CH,2DH,2EH,2FH,30H,31H,32H,33H,34H; DB 35H,36H,37H,38H,39H,3AH,3BH,3CH,3DH,3EH,3FH,40H,41H,42H,43H,44H,45H,46H,47H,48H; DB 49H,4AH,4BH,4CH,4DH,4EH,4FH,50H,51H,52H,53H,54H,55H,56H,57H,58H,59H,5AH,5BH,5CH,5DH,61H,62H,63H; TABDY3:DB 00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H; DB 00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H; DB 00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H; TABDY2:DB 00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H; DB 00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H; DB 00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H,00H,02H; TABDY4:DB 00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H; DB 00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H; DB 00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H,00H,04H; TABDY5:DB 00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H; DB 00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H; DB 00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H,00H,06H; DEL:MOV R7,#0FFH; DEL1:MOV R6,#0A0H; DEL2:MOV R5,#03H; DEL3:DJNZ R5,DEL3; DJNZ R6,DEL2; DJNZ R7,DEL1; RET; DELAY:MOV R7,#0FFH; MOV R6,#03FH; IN:DJNZ R7,IN; DJNZ R6,IN; RET; DLY8:MOV R7,#0FFH; DL:DJNZ R7,DL; RET; END

里面是桂电汇编实验的部分实验代码，希望能帮到一些需要的人

汇编语言分支结构程序设计实验，字符串比较

(1) 将例程 a 汇编连接，生成可执行文件 Hello.exe (2) 利用 Debug 调试 Hello.exe，完成下述任务： a) 指出字符串“Hello，World！”所在的段地址，以及段内起始地址； b) 将内存中字符串“world”改写成“WORLD”，并显示修改后的结果； c) 如果去掉字符串定义语句（黄色加亮）部分，程序运行结果如何？ MESS DB ‘Hello, World! ’, 0DH，0AH, 24H d) 如果去掉下述语句，程序汇编，连接以及运行过程中会有什么变化？ SSEG SEGMENT PARA STACK DW 256 DUP(?) SSEG ENDS e) 下述三条语句执行之后，AX,DS,DX 寄存器的取值各位多少？代表什么含义？针对你所操作的计算机，MESS 的地址是多少？ BEGIN：MOV AX, DSEG MOV DS, AX MOV DX, OFFSET MESS f) 如果去掉下述语句，程序执行结果有何变化？为什么？ MOV AH，9 INT 21H (3) 将例程 b 汇编连接

《微型计算机系统原理及应用》课后答案_(第3版)清华大学出版社__杨素行.pdf

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