汇编语言课件：第六章 子程序结构

1、第六章 子程序结构 过程定义伪操作 子程序的调用与返回 保存与恢复寄存器 子程序的参数传送 子程序的嵌套与递归11. 过程定义伪操作 过程名 PROC NEAR ( FAR ) 过程名 ENDP（1）NEAR属性：调用程序和子程序在同一代码段中 （段内调用）（2）FAR属性：调用程序和子程序不在同一代码段中 （段间调用）.2code segment main proc far call subr1 retmain endpsubr1 proc near retsubr1 endpcode endssegx segmentsubt proc far retsubt endp call subt

2、segx endssegy segment call far ptr subt segy ends3子程序调用：隐含使用堆栈保存返回地址 call near ptr subp (1) 保存返回地址 (2) 转子程序 call far ptr subp (1) 保存返回地址 (2) 转子程序子程序返回：ret2. 子程序的调用与返回 (SP) (IP)(IP)(CS)(SP)43. 保存与恢复寄存器subt proc far push ax push bx push cx push dx pop dx pop cx pop bx pop ax retsubt endp5(1) 通过寄存器传送参数

3、(2) 通过存储器传送参数(3) 通过地址表传送参数地址(4) 通过堆栈传送参数或参数地址(5) 多个模块之间的参数传送4. 子程序的参数传送6例：十六进制到十进制的转换（通过寄存器传送参数）hexidec segment ; 1610 assume cs: hexidec main proc farstart: push ds sub ax, ax push axrepeat: call hexibin ; 162 call crlf call binidec ; 210 call crlf jmp repeat retmain endphexidec ends end start7hexi

4、bin proc near mov bx, 0newchar: mov ah, 1 int 21h sub al, 30h jl exit cmp al, 10 jl add_to sub al, 27h cmp al, 0ah jl exit cmp al, 10h jge exitadd_to: mov cl, 4 shl bx, cl mov ah, 0 add bx, ax jmp newchar exit: rethexibin endpbinidec proc near mov cx, 10000d call dec_div mov cx, 1000d call dec_div m

5、ov cx, 100d call dec_div mov cx, 10d call dec_div mov cx, 1d call dec_div retbinidec endpdec_div proc near mov ax, bx mov dx, 0 div cx mov bx, dx mov dl, al add dl, 30h mov ah, 2 int 21h retdec_div endp 1 a b 5 31 61 62 358例：累加数组中的元素（通过存储器传送参数）data segment ary dw 1,2,3,4,5,6,7,8,9,10 count dw 10 sum

6、 dw ?data endscode segmentmain proc far assume cs:code,ds:data mov ax, data mov ds, ax call proadd mov ax,4c00h int 21hmain endpcode ends end mainproadd proc near push ax push cx push si lea si, ary mov cx, count xor ax, axnext: add ax, si add si, 2 loop next mov sum,ax pop si pop cx pop ax retproad

7、d endp9如果数据段定义如下：data segment ary dw 1,2,3,4,5,6,7,8,9,10 count dw 10 sum dw ? ary1 dw 10,20,30,40,50,60,70,80,90,100 count1 dw 10 sum1 dw ?data ends 如果直接访问内存变量，那么累加数组ary和数组ary1中的元素不能用同一个子程序 proadd。10例：累加数组中的元素（通过地址表传送参数地址）data segment ary dw 10,20,30,40,50,60,70,80,90,100 count dw 10 sum dw ? table

8、 dw 3 dup (?) ; 地址表data endscode segmentmain proc far assume cs:code, ds:data push ds sub ax, ax push ax mov ax, data mov ds, ax mov table, offset ary mov table+2, offset count mov table+4, offset sum mov bx, offset table call proadd retmain endp 11proadd proc near push ax push cx push si push di mo

9、v si, bx mov di, bx+2 mov cx, di mov di, bx+4 xor ax, axnext: add ax, si add si, 2 loop next mov di,ax pop di pop si pop cx pop ax retproadd endpcode ends end main 30d 40d 50d 60d 70d 80d 90d100d 10d ary 20d 10dcountsumtable0000001400160018000000140016(bx)(si)(di)550d12例：累加数组中的元素（通过堆栈传送参数地址）data seg

10、ment ary dw 10,20,30,40,50,60,70,80,90,100 count dw 10 sum dw ?data endsstack segment dw 100 dup (?) tos label wordstack ends13code1 segmentmain proc far assume cs:code1, ds:data, ss:stackstart: mov ax, stack mov ss, ax mov sp, offset tos mov ax, data mov ds, ax mov bx, offset ary push bx mov bx, of

11、fset count push bx mov bx, offset sum push bx call far ptr proadd mov ax, 4c00h int 21hmain endpcode1 ends14code2 segment assume cs:code2proadd proc far push bp mov bp, sp push ax push cx push si push di mov si,bp+0ah mov di,bp+8 mov cx,di mov di,bp+6code2 ends end start xor ax, axnext: add ax, si a

12、dd si, 2 loop next mov di,ax pop di pop si pop cx pop ax pop bp ret 6proadd endp(ip)(cs)sumcountarray (di) (si) (cx) (ax)(sp)(bp)(bp) (bp)+0ah (bp)+8 (bp)+6tos15多个模块之间的参数传送：局部符号：在本模块中定义，在本模块中引用的符号外部符号：在某一模块中定义，在另一模块中引用的符号 PUBLIC 符号 EXTRN 符号:类型 extrn proadd : far code1 segmentstart: call far ptr proa

13、dd code1 ends end start; proadd1.asmpublic proadd code2 segmentproadd proc far retproadd endpcode2 ends end ; proadd2.asm16例：; proadd1.asmextrn proadd : fardata segment common ary dw 1,2,3,4,5,6,7,8,9,10 count dw 10 sum dw ?data endscode1 segment main proc far assume cs:code1, ds:datastart: mov ax,

14、data mov ds, ax call far ptr proadd mov ah, 4ch int 21hmain endpcode1 ends end start17; proadd2.asmpublic proadddata segment common ary dw 1,2,3,4,5,6,7,8,9,10 count dw 10 sum dw ?data endscode2 segment proadd proc far assume cs:code2,ds:data mov ax, data mov ds, ax push ax push cx push si lea si, a

15、ry mov cx, count xor ax, ax next: add ax, si add si, 2 loop next mov sum,ax pop si pop cx pop ax retproadd endpcode2 ends end18子程序的嵌套： 主程序 子程序A 子程序B递归子程序：n! n ( n - 1 ) ( n - 2 ) 1 3! 3 21= 65. 子程序的嵌套与递归调用 call proc_Aproc_A call proc_BCall proc_Aretproc_B ret19例：计算 n!frame struc save_bp dw ? save_cs

16、_ip dw 2 dup(?) n dw ? result_addr dw ?frame ends;data segment n_v dw 3 result dw ?data ends;stack segment dw 128 dup (?) tos label wordstack endsmov ax, bp . nmov bx, bp .result_addr 0!=1 n!=n(n-1)!20code segmentmain proc far assume cs:code, ds:data, ss:stackstart: mov ax, stack ；用户堆栈地址 mov ss, ax

17、mov sp, offset tos push ds ；保存返回DOS地址 sub ax, ax push ax mov ax, data ；数据段地址 mov ds, ax mov bx, offset result ; 结构数据入栈 push bx mov bx, n_v push bx call far ptr fact retmain endpcode ends21code1 segment assume cs:code1fact proc far push bp mov bp, sp push bx push ax mov bx, bp.result_addr mov ax, bp.

18、n cmp ax, 0 je done push bx dec ax push ax call far ptr fact mov bx, bp.result_addr mov ax, bx mul bp.n jmp short returndone: mov ax,1return: mov bx, ax pop ax pop bx pop bp ret 4fact endpcode1 ends (AX) (BX) (BP)CODE中的(IP)CODE中的(CS) 3RESULT的地址第1帧 (AX) (BX) (BP)CODE1中的(IP)CODE1中的(CS) 2RESULT的地址第2帧 (AX) (BX) (BP)CODE1中的(IP)CODE1中的(CS) 1RESULT的地址第3帧 (AX) (BX) (BP)CODE1中的(IP)CODE1中的(CS) 0RESULT的地址第4帧00FA00F200E400D600C8000000F200E400D622fact proc near push ax push bp mov bp, sp mov ax, bp+6 cmp ax, 0 jne fac