<分区>
C 代码在带有 Windows 的 turbo c 上运行时工作正常，但在 gcc linux 中进入无限循环。
我尝试先在我的 ubuntu 中的 gcc 编译器中运行代码，但它进入了无限循环，出现了某种溢出错误。 所以我在 Windows 的 turbo c 中尝试了同样的方法，它运行良好。 后来我也意识到，并不是所有的windows编译器都支持这个，它们也会死循环。
这是代码:
'''
#include<stdio.h>
#include<string.h>
void chk_label();
void chk_opcode();
void READ_LINE();
struct optab
{
char code[10],objcode[10];
}myoptab[3]={
{"LDA","00"},
{"JMP","01"},
{"STA","02"}
};
struct symtab{
char symbol[10];
int addr;
}mysymtab[10];
int startaddr,locctr,symcount=0,length;
char line[20],label[8],opcode[8],operand[8],programname[10];
void PASS1()
{
FILE *input,*inter;
input=fopen("input.txt","r");
inter=fopen("inter.txt","w");
printf("LOCATION LABEL\tOPERAND\tOPCODE\n");
printf("_____________________________________");
fgets(line,20,input);
READ_LINE();
if(!strcmp(opcode,"START"))
{
startaddr=atoi(operand);
locctr=startaddr;
strcpy(programname,label);
fprintf(inter,"%s",line);
fgets(line,20,input);
}
else
{
programname[0]='\0';
startaddr=0;
locctr=0;
}
printf("\n %d\t %s\t%s\t %s",locctr,label,opcode,operand);
while(strcmp(line,"END")!=0)
{
READ_LINE();
printf("\n %d\t %s \t%s\t %s",locctr,label,opcode,operand);
if(label[0]!='\0')chk_label();
chk_opcode();
fprintf(inter,"%s %s %s\n",label,opcode,operand);
fgets(line,20,input);
}
printf("\n %d\t\t%s",locctr,line);
fprintf(inter,"%s",line);
fclose(inter);
fclose(input);
}
void PASS2()
{
FILE *inter,*output;
char record[30],part[6],value[5];
int currtxtlen=0,foundopcode,foundoperand,chk,operandaddr,recaddr=0;
inter=fopen("inter.txt","r");
output=fopen("output.txt","w");
fgets(line,20,inter);
READ_LINE();
if(!strcmp(opcode,"START")) fgets(line,20,inter);
printf("\n\nCorresponding Object code is..\n");
printf("\nH^ %s ^ %d ^ %d ",programname,startaddr,length);
fprintf(output,"\nH^ %s ^ %d ^ %d ",programname,startaddr,length);
recaddr=startaddr; record[0]='\0';
while(strcmp(line,"END")!=0)
{
operandaddr=foundoperand=foundopcode=0;
part[0]= value[0]='\0';
READ_LINE();
for(chk=0;chk<3;chk++)
{
if(!strcmp(opcode,myoptab[chk].code))
{
foundopcode=1;
strcpy(part,myoptab[chk].objcode);
if(operand[0]!='\0')
{
for(chk=0;chk<symcount;chk++)
if(!strcmp(mysymtab[chk].symbol,operand))
{
itoa(mysymtab[chk].addr,value,10);
foundoperand=1;
}
if(!foundoperand)strcpy(value,"err");
}
}
}
if(!foundopcode)
{
if(strcmp(opcode,"BYTE")==0 || strcmp(opcode,"WORD")||strcmp(opcode,"RESB"))
{strcpy(value,operand);
}}
if((currtxtlen+strlen(value)+strlen(part))<=8)
{
strcat(record,"^");
strcat(record,part);
strcat(record,value);
currtxtlen+=(strlen(value)+strlen(part));
}
else
{
printf("\nT^ %d ^%d ^%s",recaddr,currtxtlen,record);
fprintf(output,"\nT^ %d ^%d ^%s",recaddr,currtxtlen,record);
recaddr+=currtxtlen;
currtxtlen=strlen(value)+strlen(part);
strcpy(record,part);
strcat(record,value);
}
fgets(line,20,inter);
}
printf("\nT^ %d ^%d %s",recaddr,currtxtlen,record);
fprintf(output,"\nT^ %d ^%d %s",recaddr,currtxtlen,record);
printf("\nE^ %d\n",startaddr);
fprintf(output,"\nE^ %d\n",startaddr);
fclose(inter);
fclose(output);
}
void READ_LINE()
{
char buff[8],word1[8],word2[8],word3[8];
int i,j=0,count=0;
label[0]=opcode[0]=operand[0]=word1[0]=word2[0]=word3[0]='\0';
for(i=0;line[i]!='\0';i++)
{
if(line[i]!=' ')buff[j++]=line[i];
else
{
buff[j]='\0';
strcpy(word3,word2);strcpy(word2,word1);strcpy(word1,buff);
j=0;count++;
}
}
buff[j-1]='\0';
strcpy(word3,word2);
strcpy(word2,word1);
strcpy(word1,buff);
switch(count)
{
case 0:strcpy(opcode,word1);break;
case 1:{strcpy(opcode,word2);strcpy(operand,word1);}break;
case 2:{strcpy(label,word3);strcpy(opcode,word2);strcpy(operand,word1);}break;
}
}
void chk_label()
{
int k,dupsym=0;
for(k=0;k<symcount;k++)
if(!strcmp(label,mysymtab[k].symbol))
{
mysymtab[k].addr=-1;
dupsym=1;
break;
}
if(!dupsym)
{
strcpy(mysymtab[symcount].symbol,label);
mysymtab[symcount++].addr=locctr;
}
}
void chk_opcode()
{
int k=0,found=0;
for(k=0;k<3;k++)
if(!strcmp(opcode,myoptab[k].code))
{
locctr+=3;
found=1;
break;
}
if(!found)
{
if(!strcmp( opcode,"WORD")) locctr+=3;
else if (!strcmp(opcode,"RESW"))locctr+=(3*atoi(operand));
else if(!strcmp(opcode,"RESB"))locctr+=atoi(operand);
}
}
int main()
{
PASS1();
length=locctr-startaddr;
PASS2();
getch();
}
'''
这是 input.txt 文件: '''
MYPGM START 1000
STA
LOOP1 JMP LOOP2
LDA
LOOP2 JMP LOOP1
RESB 04
LDA
STA
JMP LOOP1
END
''' 在使用 linux 时，请删除 conio.h、getch() 并使用 sprintf(args...) 作为 itoa - 我在此处执行此操作，您可以在 Windows 中运行时更改它。
你可以在这里找到代码: http://vishnunotes.blogspot.com/2012/10/how-to-implement-two-pass-assembler-in.html