《計(jì)算機(jī)系統(tǒng)》過程《計(jì)算機(jī)系統(tǒng)》課程教學(xué)組2025年春季學(xué)期43512在高級(jí)語言中也稱為函數(shù)過程的調(diào)用包括將數(shù)據(jù)和控制從代碼的一部分傳遞到另一部分在進(jìn)入時(shí)為過程的局部變量分配空間，在退出時(shí)釋放空間大多數(shù)機(jī)器，只提供轉(zhuǎn)移控制到過程和從過程中轉(zhuǎn)移出控制這種簡單指令數(shù)據(jù)傳遞和局部變量的分配釋放都是通過操縱程序棧來實(shí)現(xiàn)。什么是過程？12345過程的作用代碼實(shí)例:求x的n次方—指數(shù)函數(shù)函數(shù)的調(diào)用使得代碼實(shí)現(xiàn)了模塊化，程序更簡短清晰，便于維護(hù)，開發(fā)效率和代碼復(fù)用性都得到了提高。#include<iostream>usingnamespacestd;intmain(){doublex;intn;cin>>x>>n;cout<<power(x,n)<<endl;return0;}doublepower(doublex,intn){doublep=1;while(n--)p*=x;returnp;}

過程的作用過程調(diào)用實(shí)現(xiàn)了不同函數(shù)之間的數(shù)據(jù)傳遞和控制交換。——取長補(bǔ)短，資源共享過程調(diào)用利用程序棧提高了函數(shù)間數(shù)據(jù)傳遞的效率?！掳牍Ρ?，迎刃而解過程調(diào)用通過組織不同模塊共同完成計(jì)算任務(wù)?！R心協(xié)力，合作共贏一帶一路經(jīng)濟(jì)模式可以提高程序開發(fā)的效率提高了代碼的復(fù)用性能夠使程序變得更簡短而清晰過程的作用有利于程序維護(hù)機(jī)器用棧來傳遞過程參數(shù)、存儲(chǔ)返回信息、保存寄存器用于以后恢復(fù)，以及本地存儲(chǔ)。而為單個(gè)過程分配的那部分棧稱為棧幀（stackframe）。參數(shù)傳遞寄存器數(shù)量有限避免在遞歸調(diào)用時(shí)可能發(fā)生的內(nèi)容沖突局部變量避免存儲(chǔ)區(qū)域沖突提高訪問效率寄存器保存防止有用的寄存器內(nèi)容被覆蓋提供方便的寄存器內(nèi)容保存與取回方式為什么用棧？棧為程序的調(diào)用提供了一個(gè)數(shù)據(jù)交換和暫存的場所，就像超市為各地商品的交換提供了場所一樣。由于棧中數(shù)據(jù)操作的規(guī)律性（先進(jìn)后出，如同貨架），使得數(shù)據(jù)的傳送更利于機(jī)器操作的實(shí)現(xiàn)。為什么用棧？貨物中轉(zhuǎn)先進(jìn)后出棧幀

每一個(gè)函數(shù)或過程在執(zhí)行時(shí)，都需要在內(nèi)存中分配一個(gè)空間來保存運(yùn)行時(shí)數(shù)據(jù)，這個(gè)空間由于是采用棧的方式進(jìn)行操作，所以也稱為棧幀。當(dāng)前函數(shù)或過程的棧頂?shù)刂繁４嬖?esp中，棧底地址保存在%ebp中；棧是向“下”增長的，或者說是向地址0x0處增加的，因此%esp中的值小于或等于%ebp中的值；棧幀是內(nèi)存中一段連續(xù)的內(nèi)存空間；被調(diào)用者的棧幀緊挨著調(diào)用者的棧幀；課堂習(xí)題當(dāng)前寄存器狀況如右圖，數(shù)據(jù)均為int。則執(zhí)行下列指令后：push %eaxpop %edx寄存器內(nèi)容為：%eax=0x123,%edx=0x108,%esp=0x108%eax=0x123,%edx=0x123,%esp=0x108%eax=0x123,%edx=0x123,%esp=0x104%eax=0x123,%edx=0x108,%esp=0x123一個(gè)簡單例子#include"stdio.h"voidmain(){ inta=3,b=4;

intc=sum(a,b); printf("Thesumis%d\n",c);}intsum(intx,inty){

intz=0; z=x+y; returnz;}mainsum調(diào)用返回代碼演示代碼演示main函數(shù)棧幀準(zhǔn)備局部變量a,b賦值a,b賦值后棧中情況當(dāng)前(main)棧幀代碼演示準(zhǔn)備傳遞參數(shù)：esp=0xbffff0d0a拷貝至espb拷貝至esp+4保存返回地址返回地址：0x804844a代碼演示sum函數(shù)調(diào)用保存舊ebp&準(zhǔn)備sum棧幀舊ebp：0xbffff0f8當(dāng)前（sum）棧幀代碼演示z=0賦值賦值后z存放位置及數(shù)值取傳遞參數(shù)并相加%eax(4)+%edx(3)->%eax(7)結(jié)果傳遞給z并準(zhǔn)備返回結(jié)果棧中z的值由0變7代碼演示結(jié)束調(diào)用，返回恢復(fù)main的棧幀棧幀演示0xbffff0f80xbffff0d0push %ebpmov %esp,%ebpand $0xfffffff0,%espsub $0x20,%espmovl $0x3,0x14(%esp)movl $0x4,0x18(%esp)mov 0x18(%esp),%eaxmov %eax,0x4(%esp)mov 0x14(%esp),%eaxmov %eax,(%esp)

%ebp%espmain函數(shù)棧幀準(zhǔn)備（參數(shù)及傳遞）0xbffff0e40xbffff0e80xbffff0d4a=3b=4oldebpa=3b=4棧幀準(zhǔn)備局部變量傳遞參數(shù)棧幀演示0xbffff0f80xbffff0d0call 8048464<sum>

%ebp%espmain函數(shù)棧幀準(zhǔn)備（保存返回地址）0xbffff0e40xbffff0e80xbffff0d4a=3b=4oldebpa=3b=40x804844a0xbffff0cc…………棧幀演示0xbffff0f80xbffff0d0push %ebp

%ebp%espsum的棧幀（初始化）0xbffff0e40xbffff0e80xbffff0d4a=3b=4oldebpa=3b=40x804844a0xbffff0cc0xbffff0c80xbffff0f8…………棧幀演示0xbffff0f80xbffff0d0push %ebpmov %esp,%ebpsub $0x10,%esp

%ebp%espsum的棧幀（初始化）0xbffff0e40xbffff0e80xbffff0d4a=3b=4oldebpa=3b=40x804844a0xbffff0cc0xbffff0c80xbffff0f80xbffff0b8………………棧幀演示0xbffff0f80xbffff0d0push %ebpmov %esp,%ebpsub $0x10,%espmov $0x0,-0x4(%ebp)

%ebp%espsum的棧幀（z的初值）0xbffff0e40xbffff0e80xbffff0d4a=3b=4oldebpa=3b=40x804844a0xbffff0cc0xbffff0c80xbffff0f80xbffff0b80xbffff0c4z=0………………棧幀演示0xbffff0f80xbffff0d0mov 0xc(%ebp),%eaxmov 0x8(%ebp),%edx

%ebp%espsum的棧幀（執(zhí)行）0xbffff0e40xbffff0e80xbffff0d4a=3b=4oldebpa=3b=40x804844a0xbffff0cc0xbffff0c80xbffff0f80xbffff0b80xbffff0c4z=0b=4a=3%eax%edx………………棧幀演示0xbffff0f80xbffff0d0mov 0xc(%ebp),%eaxmov 0x8(%ebp),%edxadd %edx,%eaxmov %eax,-0x4(%ebp)mov -0x4(%ebp),%eax

%ebp%espsum的棧幀（執(zhí)行）0xbffff0e40xbffff0e80xbffff0d4a=3b=4oldebpa=3b=40x804844a0xbffff0cc0xbffff0c80xbffff0f80xbffff0b80xbffff0c4z=0b=4a=3%eax%edx+%eaxz=7%eax=7………………棧幀演示0xbffff0f80xbffff0d0mov %ebp,%esppop %ebp %ebp%espsum的棧幀（返回）0xbffff0e40xbffff0e80xbffff0d4a=3b=4oldebpa=3b=40x804844a0xbffff0cc0xbffff0c80xbffff0f80xbffff0b80xbffff0c4z=7leave

=

%esp%ebp=………………棧幀演示0xbffff0f80xbffff0d0mov %ebp,%esppop %ebp

%ebpsum的棧幀（返回）0xbffff0e40xbffff0e80xbffff0d4a=3b=4oldebpa=3b=40xbffff0cc0xbffff0c80xbffff0b80xbffff0c4z=7leave

=

%esp0x804844a%eip=ret

=

pop %eip ………………嵌套調(diào)用P調(diào)用Q，Q在運(yùn)行中再調(diào)用RvoidP(){ …………

Q() …………}intQ(){ …………

R() return;}PQ調(diào)用返回R調(diào)用返回嵌套調(diào)用嵌套調(diào)用舉例oldebpvoidP(){ …………

Q() …………}intQ(){ …………

R() return;}返回地址oldebp返回地址oldebpP棧幀Q棧幀R棧幀…………遞歸調(diào)用P調(diào)用Q，Q在運(yùn)行中再調(diào)用自身voidP(){ …………

Q() …………}intQ(){ …………

Q() return;}PQ1調(diào)用返回調(diào)用返回……Qn調(diào)用返回遞歸調(diào)用遞歸調(diào)用舉例oldebpvoidP(){ …………

Q() …………}intQ(){ …………

Q() return;}返回地址oldebp返回地址oldebpP棧幀Q1棧幀Q2棧幀…………SWAP函數(shù)voidswap(int*xp,int*yp){intt0=*xp;intt1=*yp;*xp=t1;*yp=t0;}swap:pushl %ebpmovl %esp,%ebppushl %ebxmovl 8(%ebp),%edxmovl 12(%ebp),%ecxmovl (%edx),%ebxmovl (%ecx),%eaxmovl %eax,(%edx)movl %ebx,(%ecx)popl %ebxpopl %ebpretBodySetUpFinishSWAP函數(shù)voidswap(int*xp,int*yp){intt0=*xp;intt1=*yp;*xp=t1;*yp=t0;}ypxpRtnaddrOld%ebp%ebp04812offset???Old%ebx-4%esp當(dāng)前幀棧(在內(nèi)存中)調(diào)用者幀Register

Value%edx xp%ecx yp%ebx t0%eax t1movl8(%ebp),%edx#edx=xpmovl12(%ebp),%ecx#ecx=ypmovl(%edx),%ebx#ebx=*xp(t0)movl(%ecx),%eax#eax=*yp(t1)movl%eax,(%edx)#*xp=t1movl%ebx,(%ecx)#*yp=t0SWAP函數(shù)0x1200x124Rtnaddr%ebp04812Offset-4123456Address0x1240x1200x11c0x1180x1140x1100x10c0x1080x1040x100ypxp%eax%edx%ecx%ebx%esi%edi%esp%ebp0x104xymovl8(%ebp),%edx#edx=xpmovl12(%ebp),%ecx#ecx=ypmovl(%edx),%ebx#ebx=*xp(t0)movl(%ecx),%eax#eax=*yp(t1)movl%eax,(%edx)#*xp=t1movl%ebx,(%ecx)#*yp=t0SWAP函數(shù)0x1200x124Rtnaddr%ebp04812Offset-4123456Address0x1240x1200x11c0x1180x1140x1100x10c0x1080x1040x100ypxp%eax%edx%ecx%ebx%esi%edi%esp%ebp0x1240x104xymovl8(%ebp),%edx#edx=xpmovl12(%ebp),%ecx#ecx=ypmovl(%edx),%ebx#ebx=*xp(t0)movl(%ecx),%eax#eax=*yp(t1)movl%eax,(%edx)#*xp=t1movl%ebx,(%ecx)#*yp=t0SWAP函數(shù)0x1200x124Rtnaddr%ebp04812Offset-4123456Address0x1240x1200x11c0x1180x1140x1100x10c0x1080x1040x100ypxp%eax%edx%ecx%ebx%esi%edi%esp%ebp0x1240x1200x104xymovl8(%ebp),%edx#edx=xpmovl12(%ebp),%ecx#ecx=ypmovl(%edx),%ebx#ebx=*xp(t0)movl(%ecx),%eax#eax=*yp(t1)movl%eax,(%edx)#*xp=t1movl%ebx,(%ecx)#*yp=t0SWAP函數(shù)0x1200x124Rtnaddr%ebp04812Offset-4123456Address0x1240x1200x11c0x1180x1140x1100x10c0x1080x1040x100ypxp%eax%edx%ecx%ebx%esi%edi%esp%ebp0x1240x1201230x104xymovl8(%ebp),%edx#edx=xpmovl12(%ebp),%ecx#ecx=ypmovl(%edx),%ebx#ebx=*xp(t0)movl(%ecx),%eax#eax=*yp(t1)movl%eax,(%edx)#*xp=t1movl%ebx,(%ecx)#*yp=t0SWAP函數(shù)0x1200x124Rtnaddr%ebp04812Offset-4123456Address0x1240x1200x11c0x1180x1140x1100x10c0x1080x1040x100ypxp%eax%edx%ecx%ebx%esi%edi%esp%ebp4560x1240x1201230x104xymovl8(%ebp),%edx#edx=xpmovl12(%ebp),%ecx#ecx=ypmovl(%edx),%ebx#ebx=*xp(t0)movl(%ecx),%eax#eax=*yp(t1)movl%eax,(%edx)#*xp=t1movl%ebx,(%ecx)#*yp=t0SWAP函數(shù)0x1200x124Rtnaddr%ebp04812Offset-4456456Address0x1240x1200x11c0x1180x1140x1100x10c0x1080x1040x100ypxp%eax%edx%ecx%ebx%esi%edi%esp%ebp4560x1240x1201230x104xymovl8(%ebp),%edx#edx=xpmovl12(%ebp),%ecx#ecx=ypmovl(%edx),%ebx#ebx=*xp(t0)movl(%ecx),%eax#eax=*yp(t1)movl%eax,(%edx)#*xp