作业一
AREA exone,CODE,READWRITE ENTRY CODE32 MOV r0,#100 ;向寄存器中存入要比较的次数 MOV r1,#1 ;初始的两个数 MOV r2,#0 loop ADD r2,r2,r1 ;两两相加 ADD r1,r1,#1;自动加一 SUB r0,r0,#1;要加的数减一 CMP r0,#0 ;判断比较次数是否为零 BNE loop LDR r3,=RESULT STR r2,[r3] RESULT DCD 0 STOP B STOP
作业二
AREA extwo, CODE,READWRITE ENTRY CODE32 ;排序:将目标地址处的数据进行冒泡排序,从小到大 MOVS r2, #1 ;r2 = 排序完成标志,1表示未完成 again LDR r0, =data ;r0 = 目的数据块地址 MOV r1, #40;r2 = 排序字数量 SUBS r1, r1, #4 ANDS r2, r2, #1;判断排序是否完成 BEQ stop;若r2=0,完成 MOVS r2, #0;否则,标志设置为0 ;STMFD sp!, {r4} ;保存工作寄存器 judge LDR r3, [r0];读出r0地址处得值到r3 LDR r4, [r0,#4];读出r0地址处得值到r4 CMP r3, r4;比较二者的大小 BLS next;若r3<=r4,跳到next exchange MOVS r2, #1;发生数据交换,就设置标志为1 STR r3, [r0,#4];交换二者的值 STR r4, [r0] next ADDS r0, r0, #4;目标地址加4 SUBS r1, r1, #4;计数值减1 BNE judge;本趟排序未结束,跳到judge_2 B again;否则下一趟 LDMFD sp!, {r4};恢复工作寄存器 ;将程序的控制权转交给调试器 stop data DCD 9,4,6,7,8,1,3,2,0,5 STOP B STOP
作业三
;add.s汇编程序 stack_top equ 0x40002000 PRESERVE8 EXPORT add AREA add,CODE,READONLY IMPORT sum export start entry start ldr r13,=stack_top mov r0,#1 mov r1,#100 BL sum ldr r5,=result str r0,[r5] result dcd 0 end //sum.c程序 int sum(int a,int b) { int sum = 0,i; for(i=a;i<=b;i++) sum+=i; return sum; } ;add1.s汇编程序 stack_top equ 0x40002000 PRESERVE8 AREA sum,CODE,READONLY export add1 import main export start start ldr r13,=stack_top b main entry add1 ADD r2,r2,r0 ;两两相加 ADD r0,r0,#1;自动加一 SUB r1,r1,#1;要加的数减一 CMP r1,#0 ;判断比较次数是否为零 BNE add1 MOV pc,lr END //sum1.c #include<stdio.h> extern int add1(int a,int b,int c); int main() { int a = 0; printf("sum 1 to 100:"); a = add1(1,100,0); printf("%d",a); return 1; } ;strcopy.s stack_top equ 0x40002000 PRESERVE8 AREA scopy,CODE,READONLY export strcopy import main export start start ldr r13,=stack_top b main entry strcopy LDRB r2,[r1],#1 STRB r2,[r0],#1 CMP r2,#0 BNE strcopy MOV pc,lr end //main.C程序 #include<stdio.h> extern void strcopy(char *d,const char *s); int main() { const char *srcstr = "abcdefghij"; char detstr[] = "second string"; printf("before copying:\n"); strcopy(detstr,srcstr); printf("after copying:\n"); printf("%s\n%s\n",srcstr,detstr); return 1; } ;strcopy.s stack_top equ 0x40002000 PRESERVE8 export copy AREA copy,CODE,READONLY import copystr export start ENTRY start ldr r13,=stack_top ldr r0,=src ldr r1,=dst BL copystr src dcb "abcdefghij" dst dcb "helloworld" end //copystr.C程序 #include<stdio.h> void copystr(char *d,char *s) { while((*d++=*s++)!='\0'); }
作业四
1、 AREA myarea,CODE ENTRY mov r0,#9 mov r1,#15 start cmp r0,r1 bne judge beq stop sub1 sub r0,r0,r1 sub2 sub r1,r1,r0 judge cmp r0,r1 bgt sub1 blt sub2 stop b stop end 2、 arry_size equ 10 area text,code entry start mov r2,#10 ldr r0,=arry_data ldr r3,[r0] b addnext save ldr r4,=result b stop addnext ldr r1,[r0,#4]! add r3,r1,r3 sub r2,r2,#1 cmp r2,#0 beq save bne addnext arry_data dcd 1,2,3,4,5,6,7,8,9,0 space arry_size result dcd 0 stop b stop end 3、 STACK_TOP EQU 0x40001000 AREA MYEX,CODE ENTRY MOV R0,#0 MOV R1,#1 MOV R2,#2 MOV R3,#3 MOV R4,#4 MOV R5,#5 MOV R6,#6 LDR R13,=STACK_TOP STMFD R13!,{R0-R6} ;事前递减方式,保存现场 LDMFD R13!,{R3,R4,R6} ;事后递增方式,恢复现场 LDMFD R13!,{R5} LDMFD R13!,{R0,R1,R2} data dcd 1,2,3 STOP B STOP 4、 area test4,code entry start ldr r5,=data ldr r0,[r5] mov r1,#0x000000FF mov r2,#0x0000FF00 mov r3,#0x00FF0000 mov r4,#0xFF000000 ;看书完成向左移位之后再加起来 and r1,r0 lsl r1,#24 ldr r0,[r5] and r2,r0 lsl r2,#8 ldr r0,[r5] and r3,r0 lsr r3,#8 ldr r0,[r5] and r4,r0 lsr r4,#24 add r1,r1,r2 add r3,r3,r4 add r0,r1,r3 b stop data dcd 0xAABBCCDD stop b stop end