汇编语言的知识点总结

;输出字符串函数 prompt proc mov ah, 09h int 21h ret prompt endp ;输出回车换行符函数 crlf proc mov dl, 0dh mov ah, 2 int 21h mov dl, 0ah mov ah, 2 int 21h ret crlf endp ;输出空格符函数 blank proc mov dl, 20h mov ah, 2 int 21h ret blank endp ;二进制的输入函数 ;输入范围0~1111111111111111 inb proc push cx inbstart: mov bx, 0 accept: mov ah, 1 int 21h cmp al, 0dh je inbexit cmp al, 30h jl inberr cmp al, 31h ja inberr sub al, 30h mov ah, 0 mov ax, bx mov cx, 2 mul cx add bx, ax jmp accept inbexit: pop cx ret inberr: lea dx, 'bad format...$' call prompt jmp inbstart inb endp ;八进制的输入函数 ;范围:0-177777 inq proc push cx pop cx ret inq endp ;十进制的输入函数 ;范围:0-65535 ind proc push cx indstart: mov bx, 0 accept: mov ah, 1 int 21h cmp al, 0dh je indexit cmp al, 30h jl inderr cmp al, 39h ja inderr sub al, 30h mov ah, 0 xchg ax, bx mov cx, 10 mul cx add bx, ax jmp accept indexit: pop cx ret inderr: mov dx, offset 'bad format...$' call prompt jmp indstart ind endp ;十六进制的输入函数 ;范围:0-0FFFFH inh proc push cx inhstart: mov bx, 0 accept: mov ah, 1 int 21h cmp al, 0dh je inhexit cmp al, 30h jl inherr cmp al, 66h ;'f' ja inherr cmp al, 39h ;'9' jl num cmp al, 41h ;'A' jl inherr cmp al, 46h ;'F' ja lowercase sub al, 7h ;'A'-':'=7h jmp num lowercase: cmp al, 61h ;'a' jl inherr cmp al, 66h ;'f' ja inherr sub al, 27h ;'a'-':'=27h num: and ax, 0fh xchg ax, bx mov cx, 16 ;mov cx, 4 mul cx ;shl ax add bx, ax jmp accept inhexit: pop cx ret inherr: lea dx, 'bad format...$' call prompt jmp inhstart inh endp ;二进制的输出函数 ;范围:0-1111111111111111 ;call: 要输出的数字放在bx中传入 outb proc push cx mov nozero, 0 ;like a boolean variable mov cl, 16 nextbit: mov dl, 0 test bx, 8000h je disp mov nozero, 1 mov dl, 1 disp: cmp nozero, 0 je continue add dl, 30h mov ah, 2 int 21h continue: shl bx, 1 loop nextbit cmp nozero, 0 jne outbexit mov dl, 30h ;output '0' because the number in bx is zero mov ah, 2 int 21h outbexit: pop cx ret outb endp ;八进制的输出函数 ;范围:0-177777 ;call: 要输出的数字放在bx中传入 ;十进制的输出函数 ;范围:0-65535 ;call: 要输出的数字放在bx中传入 outd proc push cx mov nozero, 0 ;like a boolean variable mov cx, 10000 call decdiv mov cx, 1000 call decdiv mov cx, 100 call decdiv mov cx, 10 call decdiv mov cx, 1 call decdiv cmp nozero, 0 jne outdexit mov dl, 30h mov ah, 2 int 21h outdexit: pop cx ret ;---sub proc--- ;call: 被除数在bx传入,除数在cx传入 ;ret: 打印商,余数送bx decdiv proc mov ax, bx mov dx, 0 div cx mov bx, dx mov dl, al cmp dl, 0 jne dispdigit cmp nozero, 0 jne dispdigit jmp decdivexit dispdigit: mov nozero, 1 add dl, 30h mov ah, 2 int 21h decdivexit: ret decdiv endp ;---sub proc--- outd endp ;十六进制的输出函数 ;范围:0-0FFFFH(或0-0ffffh) ;输出十六进制用大写字母(A-F表示) ;call: 要输出的数字放在bx中传入 outh proc push cx mov ch, 4 mov nozero, 0 ;like a boolean variable next4bits: mov cl, 4 rol bx, cl mov al, bl and al, 0fh cmp al, 10 jl dispdigit add al, 7h ;if disp 'a-f' ,should add 27h dispdigit: cmp al, 0 jne dispnozero cmp nozero, 0 je continue dispnozero: mov nozero, 1 add al, 30h mov dl, al mov ah, 2 int 21h continue: dec ch jnz next4bits cmp nozero, 0 jne outhexit mov dl, 30h mov ah, 2 int 21h outhexit: pop cx ret outh endp ;冒泡排序函数(降序)(sort in DW array<2 bytes>) bubble proc push cx mov cx, count ;NOTICE: count = nums.length-1 outloop: mov di, cx mov si, 0 inloop: mov ax, nums[si] cmp ax, nums[si+2] ;nums[si+1], if sort in 8 byte jae incontinue xchg ax, nums[si+2] ;nums[si+1], if sort in 8 byte xchg ax, nums[si] incontinue: add si, 2 ;add si, 1, if sort in 8 byte loop inloop mov cx, di loop outloop pop cx ret bubble endp ;查找最小ASCII码 ;call: 被查找ASCII串码放在buff中 ;ret: 找到的最小ASCII码将被放在minascii中返回 getmin proc push cx lea si, buff+2 mov cl, num+1 and cx, 0fh mov bl, [si] next: inc si cmp bl, [si] jle continue mov bl, [si] continue: loop next mov minascii, bl pop cx ret getmin endp ;统计非字符和非数字的个数 ;call: 被统计ASCII串码放在buff中 ;ret: 统计的数字将被放在sum中返回 count proc push cx mov cl, buff+1 lea si, buff+2 mov sum, 0 next: mov al, [si] cmp al, '0' ;30h jb yes cmp al, '9' ;39h jb no cmp al, 'A' ;41h jb yes cmp al, 'Z' ;5ah jb no cmp al, 'a' ;61h jb yes cmp al, 'z' ;7ah jb no jmp yes yes: inc byte ptr sum no: inc si loop next pop cx ret count endp

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