这是笔者的计算系统概论这门课的实验之一，实验内容是实现简易的LC-3汇编器，将汇编码转换为机器码，原理较为简单，即利用两次遍历，第一次获取标签信息，第二次实现转换。但具体用代码实现极其繁琐，特别是不止18个指令要一个一个写，所以把写好的代码放在下面供大家参考，注释也写了，如果有看不懂的或有什么问题可以直接问我。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#define MAX_LINE_LENGTH 100
//标签链表结构体，用于储存标签名以及标签位置
typedef struct Lable{
char * name;
int pos;
struct Lable *next;
}Lable;
// Function prototypes
void read_asm_file(const char *filename, char lines[][MAX_LINE_LENGTH], int *num_lines);
void write_output_file(const char *filename, const char *output[], int num_lines);
void assemble(char lines[][MAX_LINE_LENGTH], int num_lines, char *output[]);
char * translate_instruction(char *instruction,int line,Lable *head);
char *bin_transfer(char *str,int bit);
char *reg_num(char *str);
Lable *get_lable_pos(char lines[][MAX_LINE_LENGTH],int line_index);
char *word_ascii(char word);
char **my_strtok(const char *source, char flag);
int getIndexOfSigns(char ch);
long hexToDec(char *source);
void reverse(char* left, char* right);
char* to_binary(int n, int m);
// TODO: Define any additional functions you need to implement the assembler, e.g. the symbol table.
int main(int argc, char *argv[])
//int main()
// Command-line argument parsing
if (argc != 3)
fprintf(stderr, "Usage: %s <input_file.asm> <output_file.txt>\n", argv[0]);
return 1;
char input_filename[100];
char output_filename[100];
strcpy(input_filename, argv[1]);
strcpy(output_filename, argv[2]);
// printf("input input_filename:\n");
// scanf("%s",&input_filename);
// printf("input output_filename:\n");
// scanf("%s",&output_filename);
char lines[100][MAX_LINE_LENGTH]; // Assuming a maximum of 100 lines
int num_lines = 0;
read_asm_file(input_filename, lines, &num_lines);
char *output[100]; // Output array of strings
for (int i = 0; i < 100; i++)
output[i] = (char *)malloc(MAX_LINE_LENGTH * sizeof(char));
assemble(lines, num_lines, output);
write_output_file(output_filename, (const char **)output, num_lines);
// Free allocated memory
for (int i = 0; i < 100; i++)
free(output[i]);
return 0;
void read_asm_file(const char *filename, char lines[][MAX_LINE_LENGTH], int *num_lines)
FILE *file = fopen(filename, "r");
if (file == NULL)
fprintf(stderr, "Unable to open file: %s\n", filename);
exit(1);
char line[MAX_LINE_LENGTH];
while (fgets(line, MAX_LINE_LENGTH, file))
strcpy(lines[*num_lines], line);
printf("%s",lines[*num_lines]);
(*num_lines)++;
fclose(file);
void write_output_file(const char *filename, const char *output[], int num_lines)
FILE *file = fopen(filename, "w");
if (file == NULL)
fprintf(stderr, "Unable to open file: %s\n", filename);
exit(1);
for (int i = 0; i < num_lines; i++)
fprintf(file, "%s\n", output[i]);
fclose(file);
int trans_line = 1;
void assemble(char lines[][MAX_LINE_LENGTH], int num_lines, char *output[])
// TODO: Implement the assembly process
// Implement the 2-pass process described in textbook.
Lable *lable;
lable = get_lable_pos(lines,num_lines);//第一次遍历创建标签链表
char *tem_output;
for (int i = 0; i < num_lines; i++)
tem_output = translate_instruction(lines[i],i+trans_line,lable);//临时指针存转码结果
strcpy(output[i],tem_output);
printf("\n%s",output[i]);//打印结果
char * translate_instruction(char *instruction,int line,Lable *head)
char *machine_code;//要返回的机器码
machine_code = (char *)malloc(MAX_LINE_LENGTH * sizeof(char));//分配空间
char *condition_code;//条件码
//下面是用到的29个指令
char str1[] = ".ORIG";
char str2[] = "ADD";
char str3[] = "AND";
char str4[] = "BR";
char str4_1[] = "BRN";
char str4_2[] = "BRZ";
char str4_3[] = "BRP";
char str4_4[] = "BRNZ";
char str4_5[] = "BRNP";
char str4_6[] = "BRZP";
char str4_7[] = "BRNZP";//BR子指令
char str5[] = "JMP";
char str6[] = "RET";
char str7[] = "JSR";
char str8[] = "JSRR";
char str9[] = "LD";
char str10[] = "LDI";
char str11[] = "LDR";
char str12[] = "LEA";
char str13[] = "NOT";
char str14[] = "RTI";
char str15[] = "ST";
char str16[] = "STI";
char str17[] = "STR";
char str18[] = "TRAP";
char str19[] = ".BLKW";
char str20[] = ".STRINGZ";
char str21[] = ".FILL";
char str22[] = ".END";
char ** single ;//用来存分割后的字符串
char space = ' ';//按空格分割
char enter = '\n';//按换行分割，因为字符串最后有\n
char *reg_number = "000";
char *imm_number = "1";//一些机器码中用到的码
single = my_strtok(instruction,enter);
single = my_strtok(single[0],space);//第一次分割，得到各个子字符串
int bin_num;
int count;//计数，表示是分割后的第几个字符串
for(count = 0;;count++)
if(strcmp(single[count],str1) == 0 || strcmp(single[count],str21) == 0)//.ORIG or .FILL
single = my_strtok(single[count+1],enter);//去换行操作
machine_code= bin_transfer(single[0],16);//将语句后面带的数直接转为16位二进制编码
break;
if(strcmp(single[count],str2) == 0 || strcmp(single[count],str3) == 0)//ADD or AND
if(strcmp(single[count],str2) == 0)
condition_code = "0001";
condition_code = "0101";//先存入指令码，后面类似
strcpy(machine_code,condition_code);
count ++;
if(single[count][0] != '#' && single[count][0] != 'x')//这句并没有多大用处，因为ADD或AND后面两个都是寄存器
char *ad_binary_1 = reg_num(single[count++]);//判断寄存器
strcat(machine_code,ad_binary_1);
if(single[count][0] != '#' && single[count][0] != 'x')
char *ad_binary_2 = reg_num(single[count++]);
strcat(machine_code,ad_binary_2);
single = my_strtok(single[count],enter);
if(single[0][0] != '#' && single[0][0] != 'x')//检测是立即数还是寄存器
strcat(machine_code,reg_number);
char *ad_binary_3 = reg_num(single[0]);
strcat(machine_code,ad_binary_3);
strcat(machine_code,imm_number);
char *ad_bin;
ad_bin = bin_transfer(single[0],5);
strcat(machine_code,ad_bin);
break;
if(strcmp(single[count],str4) == 0 || strcmp(single[count],str4_1) == 0 || strcmp(single[count],str4_2) == 0 || strcmp(single[count],str4_3) == 0 || strcmp(single[count],str4_4) == 0 || strcmp(single[count],str4_5) == 0 || strcmp(single[count],str4_6) == 0 || strcmp(single[count],str4_7) == 0)
if(strcmp(single[count],str4) == 0 || strcmp(single[count],str4_7) == 0)//BR or BRNZP
condition_code = "0000111";
if(strcmp(single[count],str4_1) == 0)//BRN
condition_code = "0000100";
if(strcmp(single[count],str4_2) == 0)//BRZ
condition_code = "0000010";
if(strcmp(single[count],str4_3) == 0)//BRP
condition_code = "0000001";
if(strcmp(single[count],str4_4) == 0)//BRNZ
condition_code = "0000110";
if(strcmp(single[count],str4_5) == 0)//BRNP
condition_code = "0000101";
if(strcmp(single[count],str4_6) == 0)//BRZP
condition_code = "0000011";
strcpy(machine_code,condition_code);
count++;
single = my_strtok(single[count],enter);
if(single[0][0] == '#' || single[0][0] == 'x')//检测是立即数还是标签
char *br_bin = bin_transfer(single[0],9);
strcat(machine_code,br_bin);
Lable *p = head;
char *br_bin_2;
char *imm_0 = "000000000";
while(p!= NULL)//遍历标签链表找到对应标签所在位置（行数）
if(strcmp(single[0],p->name) == 0)
int sub = p->pos - 1 - line;//标签行数减PC增量减当前行数
if(sub == 0)
strcat(machine_code,imm_0);
break;
br_bin_2 = to_binary(sub,9); //得到差值并转为9位二进制编码
strcat(machine_code,br_bin_2);
break;
p = p->next;
break;
char *jmp_bin_2 = "000000";
if(strcmp(single[count],str5) == 0 || strcmp(single[count],str6) == 0)//JMP or RET
if(strcmp(single[count],str5) == 0)
condition_code = "1100000";
strcpy(machine_code,condition_code);
count ++ ;
single = my_strtok(single[count],enter);
char *jmp_bin = reg_num(single[0]);
strcat(machine_code,jmp_bin);
strcat(machine_code,jmp_bin_2);
condition_code = "1100000111000000";
strcpy(machine_code,condition_code);
break;
if(strcmp(single[count],str7) == 0 || strcmp(single[count],str8) == 0)//JSR or JSRR
if(strcmp(single[count],str7) == 0)
condition_code = "01001";
strcpy(machine_code,condition_code);
count ++ ;
single = my_strtok(single[count],enter);
if(single[0][0] == '#' || single[0][0] == 'x')
char *jsr_num_bin = bin_transfer(single[0],11);
strcat(machine_code,jsr_num_bin);
Lable *jsr_p = head;//同样的检测标签并返回，只不过变为了11位
jsr_p->name = (char *)malloc(100 *sizeof(char));
char *jsr_bin_2;
while(jsr_p != NULL)
if(strcmp(single[0],jsr_p->name) == 0)
int jsr_sub = jsr_p->pos - 1 - line ;
jsr_bin_2 = to_binary(jsr_sub,11);
break;
jsr_p = jsr_p->next;
strcat(machine_code,jsr_bin_2);
condition_code = "0100000";
strcpy(machine_code,condition_code);
count++;
single = my_strtok(single[count],enter);
char *jsrr_bin = reg_num(single[0]);
strcat(machine_code,jsrr_bin);
strcat(machine_code,jmp_bin_2);
break;
if(strcmp(single[count],str9) == 0 || strcmp(single[count],str10) == 0 || strcmp(single[count],str15) == 0 ||strcmp(single[count],str16) == 0)//LD or LDI or ST or STI
if(strcmp(single[count],str9) == 0)
condition_code = "0010";
else if(strcmp(single[count],str10) == 0)
condition_code = "1010";
else if(strcmp(single[count],str15) == 0)
condition_code = "0011";
condition_code = "1011";
strcpy(machine_code,condition_code);
count ++ ;
char *ld_bin = reg_num(single[count]);
strcat(machine_code,ld_bin);
count ++ ;
single = my_strtok(single[count],enter);
if(single[0][0] == '#' || single[0][0] == 'x')
char *ld_num_bin = bin_transfer(single[0],9);
strcat(machine_code,ld_num_bin);
Lable *ld_p = head;
ld_p->name = (char *)malloc(100 *sizeof(char));
char *ld_bin_2;
while(ld_p != NULL)
if(strcmp(single[0],ld_p->name) == 0)
int ld_sub = ld_p->pos - 1 - line;
ld_bin_2 = to_binary(ld_sub,9);
break;
ld_p = ld_p->next;
strcat(machine_code,ld_bin_2);
break;
if(strcmp(single[count],str11) == 0 || strcmp(single[count],str17) == 0)//LDR or STR
if(strcmp(single[count],str11) == 0)
condition_code = "0110";
condition_code = "0111";
strcpy(machine_code,condition_code);
count ++ ;
char *ldr_bin_1 = reg_num(single[count]);
strcat(machine_code,ldr_bin_1);
count ++ ;
char *ldr_bin_2 = reg_num(single[count]);
strcat(machine_code,ldr_bin_2);
count ++ ;
single = my_strtok(single[count],enter);
char *ldr_bin_3 = bin_transfer(single[0],6);
strcat(machine_code,ldr_bin_3);
break;
if(strcmp(single[count],str12) == 0)//LEA
condition_code = "1110";
strcpy(machine_code,condition_code);
count ++;
char *lea_bin_1 = reg_num(single[count]);
strcat(machine_code,lea_bin_1);
count++;
single = my_strtok(single[count],enter);
if(single[0][0] == '#' || single[0][0] == 'x')
char *lea_num_bin = bin_transfer(single[0],9);
strcat(machine_code,lea_num_bin);
Lable *lea_p = head;
lea_p->name = (char *)malloc(100 *sizeof(char));
char *lea_bin_2;
while(lea_p!= NULL)
if(strcmp(single[0],lea_p->name) == 0)
int lea_sub = lea_p->pos - 1 - line;
lea_bin_2 = to_binary(lea_sub,9);
break;
lea_p = lea_p->next;
strcat(machine_code,lea_bin_2);
break;
if(strcmp(single[count],str13) == 0)//NOT
condition_code = "1001";
strcpy(machine_code,condition_code);
count ++ ;
char *not_bin_1 = reg_num(single[count]);
strcat(machine_code,not_bin_1);
count ++ ;
single = my_strtok(single[count],enter);
char *not_bin_2 = reg_num(single[0]);
strcat(machine_code,not_bin_2);
char *not_bin_3 = "111111";
strcat(machine_code,not_bin_3);
break;
if(strcmp(single[count],str14) == 0)//RTI
condition_code= "1000000000000000";
strcpy(machine_code,condition_code);
break;
if(strcmp(single[count],str18) == 0)//.TRAP
condition_code = "11110000";
strcpy(machine_code,condition_code);
count++;
single = my_strtok(single[count],enter);
char *trap_bin = bin_transfer(single[0],8);
strcat(machine_code,trap_bin);
break;
if(strcmp(single[count],str19) == 0)//.BLKW
count++;
int blkw_dec;
if(single[count][0] == 'x')
char blkw_tem1 = 'x';
single = my_strtok(single[count],blkw_tem1);
blkw_dec = hexToDec(single[0]);
if(single[count][0] == '#')
char blkw_tem2 = '#';
single = my_strtok(single[count],blkw_tem2);
blkw_dec = strtol(single[0],NULL,10);
trans_line += blkw_dec - 1;
char *blkw_bin_1 = "0000000000000000";
char *blkw_bin_2 = "0000000000000000\n";
if(blkw_dec == 1)
machine_code = "0000000000000000";
for(int bi = 0;bi<blkw_dec - 1;bi++)//表示存入多少行的16位的0
if(bi == 0)
condition_code = "0000000000000000\n" ;
strcpy(machine_code,condition_code);
strcat(machine_code,blkw_bin_2);
strcat(machine_code,blkw_bin_1);
break;
if(strcmp(single[count],str20) == 0)//.STRINGZ
char ascii_bin[100] = {0};
count++;
char *space_1 = " ";
while(single[count]!=NULL)
strcat(ascii_bin,single[count]);
strcat(ascii_bin,space_1);
count ++;
int trans_pos = strlen(ascii_bin) - 3;
trans_line += trans_pos;//全局变量控制当前语句行数，只有BLKW和STRINGZ会改变
single = my_strtok(ascii_bin,enter);
int si = 1;
char *enter_1 = "\n";//换行
while(single[0][si]!='"' && single[0][si+1]!='\0')//把双引号内的字符串一个一个转换为ascii值对应的二进制数并存入
if(si == 1)
condition_code = word_ascii(single[0][si]);
strcpy(machine_code,condition_code);
strcat(machine_code,enter_1);
else if(single[0][si+1]!='"')
char *str_bin = word_ascii(single[0][si]);
strcat(machine_code,str_bin);
strcat(machine_code,enter_1);
char *str_bin_2 = word_ascii(single[0][si]);
strcat(machine_code,str_bin_2);
char *zero = "0000000000000000";
strcat(machine_code,enter_1);
strcat(machine_code,zero);
si++;
break;
if(strcmp(single[count],str22) == 0)//.END
machine_code = "\0";
break;
return machine_code;
char *word_ascii(char word)//字母转换为ascii值并转换为16位二进制编码
int ascii = (int)word;
char *ascii_bin = to_binary(ascii,16);
return ascii_bin;
Lable *get_lable_pos(char lines[][MAX_LINE_LENGTH],int line_index)
char *str[] = {".ORIG","ADD","AND","BR","BRN",
"BRZ","BRP","BRNZ","BRNP","BRZP",
"BRNZP","JMP","RET","JSR","JSRR",
"LD","LDI","LDR","LEA","NOT","RTI",
"ST","STI","STR","TRAP",".BLKW",
".STRINGZ",".FILL",".END"};
char **act_str;
Lable *lable_head = (Lable*)malloc(sizeof(Lable)); //标签链表头结点
int j = 0;
int temp = 0;
int str_pos = 0;
for(int k = 0 ;k<line_index;k++)
char *instroction = lines[k];
char space_lable = ' ';
char enter_lable = '\n';
char **act_str_son;
act_str = my_strtok(instroction,space_lable);
act_str_son = my_strtok(act_str[0],enter_lable);
temp = 0;
for(int j = 0;j<29;j++)
if(strcmp(act_str_son[0],str[j])!=0)
temp++;
if(temp == 29)//当不是这29个指令时，记为标签，头插法创建标签链表
Lable *p = (Lable*)malloc(sizeof(Lable));
p->name = (char*)malloc(100 * sizeof(char));
strcpy(p->name,act_str_son[0]);
p->pos = k + str_pos + 1;//记录标签位置
p->next = lable_head ->next;
lable_head->next = p;
if(strcmp(act_str[1],str[26]) == 0)//STRINGZ进行更改
char str_len[100] = {0};
char *space_2 = " ";
int m = 2;
while(act_str[m]!=NULL)
strcat(str_len,act_str[m]);
strcat(str_len,space_2);
m ++;
str_pos += strlen(str_len) - 4;//减4是两个双引号，多加的空格和最后的换行
if(strcmp(act_str[1],str[25]) == 0)//BLKW进行更改
char lable_tem = '#';
act_str = my_strtok(act_str_son[2],lable_tem);
int lable_dec = strtol(act_str[0],NULL,10);
str_pos += lable_dec;
return lable_head;
char *reg_num(char *str)//检测寄存器模块，输出为寄存器对应二进制编码
char reg1[] = "R0";
char reg2[] = "R1";
char reg3[] = "R2";
char reg4[] = "R3";
char reg5[] = "R4";
char reg6[] = "R5";
char reg7[] = "R6";
char reg8[] = "R7";
char tem = ',';
char **reg_str;
reg_str = my_strtok(str,tem);//去逗号
char *bin = (char *)malloc(sizeof(char) * 3);
if(strcmp(reg_str[0],reg1) == 0)
bin = "000";
if(strcmp(reg_str[0],reg2) == 0)
bin = "001";
if(strcmp(reg_str[0],reg3) == 0)
bin = "010";
if(strcmp(reg_str[0],reg4) == 0)
bin = "011";
if(strcmp(reg_str[0],reg5) == 0)
bin = "100";
if(strcmp(reg_str[0],reg6) == 0)
bin = "101";
if(strcmp(reg_str[0],reg7) == 0)
bin = "110";
if(strcmp(reg_str[0],reg8) == 0)
bin = "111";
return bin;
char **my_strtok(const char *source, char flag)
char **pt;
int j, n = 0;
int count = 1;
int len = strlen(source);
// 动态分配一个 *tmp，静态的话，变量len无法用于下标
char *tmp = (char*)malloc((len + 1) * sizeof(char));
tmp[0] = '\0';
for (int i = 0; i < len; ++i)
if (source[i] == flag && source[i+1] == '\0')
continue;
else if (source[i] == flag && source[i+1] != flag)
count++;
// 多分配一个char*，是为了设置结束标志
pt = (char**)malloc((count+1) * sizeof(char*));
count = 0;
for (int i = 0; i < len; ++i)
if (i == len - 1 && source[i] != flag)
tmp[n++] = source[i];
tmp[n] = '\0'; // 字符串末尾添加空字符
j = strlen(tmp) + 1;
pt[count] = (char*)malloc(j * sizeof(char));
strcpy(pt[count++], tmp);
else if (source[i] == flag)
j = strlen(tmp);
if (j != 0)
tmp[n] = '\0'; // 字符串末尾添加空字符
pt[count] = (char*)malloc((j+1) * sizeof(char));
strcpy(pt[count++], tmp);
// 重置tmp
n = 0;
tmp[0] = '\0';
tmp[n++] = source[i];
free(tmp);
// 设置结束标志
pt[count] = NULL;
return pt;
void reverse(char* left, char* right) //翻转数组
while (left < right) {
char tmp = *right;
*right = *left;
*left = tmp;
left++;
right--;
char* to_binary(int n, int m)//假设要求m位二进制数
char a[10000] = { '\0' };
int i = 0;
int n_2 = 0;
if(n<0)//若是负数
n = abs(n);
n_2 = pow(2,m-1);
n = n_2 - n;//2的n-1次方减去绝对值得补码
while (n != 0)
a[i++] = '0' + n % 2;
n = n / 2;
reverse(a, a + strlen(a) - 1);
char b[10000] = {'1'};
for (int i = 1; i < m - strlen(a); i++)
b[i] = '0';
return strcat(b,a);
while (n != 0)
a[i++] = '0' + n % 2;
n = n / 2;
reverse(a, a + strlen(a) - 1);
char b[10000] = {'\0'};
for (int i = 0; i < m - strlen(a); i++)
b[i] = '0';
return strcat(b,a);
long hexToDec(char *source)//十六进制转十进制
long sum = 0;
long t = 1;
int i, len;
len = strlen(source);
for(i=len-1; i>=0; i--)
sum += t * getIndexOfSigns(*(source + i));
t *= 16;
return sum;
int getIndexOfSigns(char ch)
if(ch >= '0' && ch <= '9')
return ch - '0';
if(ch >= 'A' && ch <='F')
return ch - 'A' + 10;
if(ch >= 'a' && ch <= 'f')
return ch - 'a' + 10;
return -1;
char *bin_transfer(char *str,int bit)//"xn" or "#n"转换为二进制编码字符串
int dec;
char *bin = (char *)malloc(sizeof(char) * 16);
int index = 0;
char **bin_str;
if(str[0] == 'x')
char tem = 'x';
bin_str = my_strtok(str,tem);
dec = hexToDec(bin_str[0]);
if(str[0] == '#')
char tem = '#';
bin_str = my_strtok(str,tem);
dec = strtol(bin_str[0],NULL,10);
char *binary = to_binary(dec,bit);
return binary;
1月25日更：
注意，这个代码中的.STRINGZ实现的是把字符串存入后再把下一个内存空间置为x0000，即和标准功能一样，但如果最后一个.STRINGZ不需要这样做的话（即.END前面跟的是.STRINGZ，末尾没必要加x0000），需要修改代码，加一个全局变量来控制输出，如下所示：
int end_flag = 0;
void assemble(...)
//...下面的内容放在for循环里
char check_space = ' ';
char check_enter = '\n';
if(i!=num_lines-1)
char **check = my_strtok(lines[i],check_space);
char **check_next = my_strtok(lines[i+1],check_enter);
int k = 0;
char check_str1[] = ".STRINGZ";
char check_str2[] = ".END";
while(check[k]!=NULL)
if(strcmp(check[k],check_str1) == 0)
if(strcmp(check_next[0],check_str2) == 0)
end_flag = 1;
//同时修改translate函数中的.STRINGZ分支，只需判断end_flag即可
char * translate_instruction(...)
//...
char *str_bin_2 = word_ascii(single[0][si]);
strcat(machine_code,str_bin_2);
char *zero = "0000000000000000";
strcat(machine_code,enter_1);
if(end_flag == 0)
strcat(machine_code,zero);
枚举和定义: 代码开始部分定义了若干枚举类型和宏定义，用于表示寄存器、条件标志位、操作码、内存地址等关键元素。例如，R_PC代表程序计数器，OP_ADD代表加法操作，MEMORY_MAX定义了内存的最大大小等。
终端输入gcc -S hello.c 就会生成hello.s。终端输入gcc -o prog hello.c sum.c。可添加asm插件，使汇编代码有颜色便于阅读。终端输入objdump -d hello.o。3、生成二进制目标文件hello.o。终端输入gcc -c hello.c。4、生成二进制可执行文件prog。
1: #define N 302: #include3: void main()4: {00401010 push ebp00401011 mov ebp,esp00401013 sub esp,6Ch00401016 push ebx00401017 push esi004010...
◦ 计算的结果存储在x3101
用 LC3编写机器代码，实现简单的程序。初步学会LC3代码的编写，进一步加深了关于LC3汇编代码指令的相关学习应用。学会了关于LC3里面跳转指令，循环结构，基本加减实现。学会寄存器的灵活运用。...
利用LC3EDIT输入机器代码程序（0/1模式）并创建可执行目标程序。
利用LC3EDIT输入机器代码程序（hex模式）并创建可执行目标程序。
利用LC3EDIT输入汇编代码程序并创建可执行目标程
一位老师需要你帮忙决定学生的成绩，她想要根据学生分数在班上的排名和考试分数一起决定学生最后的成绩等级。获得A的学生人数必须存储在x4100，获得B的人数必须存储在x4101。如果学生不能拿A，但是分数排名在全班的50%之前，且考试分数达到75及以上，则学生可以获得B；4.对于寄存器的使用以及相应操作码的用法都更为熟悉，掌握了利用汇编语言解决问题的思路。如果学生的分数排名在全班的25%之前，且考试分数达到85分及以上，则学生可以获得A；你的程序必须给学生的分数排序，然后计算出获得A和B的学生人数。
