在下面代码中加入PL0语言输入输出扩展
这是.h文件
#include <stdio.h>
#define norw 11 // no. of reserved words
#define txmax 100 // length of identifier table
#define nmax 14 // max. no. of digits in numbers
#define al 10 // length of identifiers
#define amax 2047 // maximum address
#define levmax 3 // maximum depth of block nesting
#define cxmax 2000 // size of code array
#define nul 0x1
#define ident 0x2
#define number 0x4
#define plus 0x8
#define minus 0x10
#define times 0x20
#define slash 0x40
#define oddsym 0x80
#define eql 0x100
#define neq 0x200
#define lss 0x400
#define leq 0x800
#define gtr 0x1000
#define geq 0x2000
#define lparen 0x4000
#define rparen 0x8000
#define comma 0x10000
#define semicolon 0x20000
#define period 0x40000
#define becomes 0x80000
#define beginsym 0x100000
#define endsym 0x200000
#define ifsym 0x400000
#define thensym 0x800000
#define whilesym 0x1000000
#define dosym 0x2000000
#define callsym 0x4000000
#define constsym 0x8000000
#define varsym 0x10000000
#define procsym 0x20000000
enum object
{
constant, variable, proc
};
enum fct
{
lit, opr, lod, sto, cal, Int, jmp, jpc // functions
};
/* lit 0, a : load constant a
opr 0, a : execute operation a
lod l, a : load variable l, a
sto l, a : store variable l, a
cal l, a : call procedure a at level l
Int 0, a : increment t-register by a
jmp 0, a : jump to a
jpc 0, a : jump conditional to a */
typedef struct
{
enum fct f; // function code
long l; // level
long a; // displacement address
} instruction;
char* err_msg[] =
{
/* 0 */ "",
/* 1 */ "Found ':=' when expecting '='.",
/* 2 */ "There must be a number to follow '='.",
/* 3 */ "There must be an '=' to follow the identifier.",
/* 4 */ "There must be an identifier to follow 'const', 'var', or 'procedure'.",
/* 5 */ "Missing ',' or ';'.",
/* 6 */ "Incorrect procedure name.",
/* 7 */ "Statement expected.",
/* 8 */ "Follow the statement is an incorrect symbol.",
/* 9 */ "'.' expected.",
/* 10 */ "';' expected.",
/* 11 */ "Undeclared identifier.",
/* 12 */ "Illegal assignment.",
/* 13 */ "':=' expected.",
/* 14 */ "There must be an identifier to follow the 'call'.",
/* 15 */ "A constant or variable can not be called.",
/* 16 */ "'then' expected.",
/* 17 */ "';' or 'end' expected.",
/* 18 */ "'do' expected.",
/* 19 */ "Incorrect symbol.",
/* 20 */ "Relative operators expected.",
/* 21 */ "Procedure identifier can not be in an expression.",
/* 22 */ "Missing ')'.",
/* 23 */ "The symbol can not be followed by a factor.",
/* 24 */ "The symbol can not be as the beginning of an expression.",
/* 25 */ "",
/* 26 */ "",
/* 27 */ "",
/* 28 */ "",
/* 29 */ "",
/* 30 */ "",
/* 31 */ "The number is too great.",
/* 32 */ "There are too many levels."
};
char ch; // last character read
unsigned long sym; // last symbol read
char id[al+1]; // last identifier read
long num; // last number read
long cc; // character count
long ll; // line length
long kk, err;
long cx; // code allocation index
char line[81];
char a[al+1];
instruction code[cxmax+1];
char word[norw][al+1];
unsigned long wsym[norw];
unsigned long ssym[256];
char mnemonic[8][3+1];
unsigned long declbegsys, statbegsys, facbegsys;
struct
{
char name[al+1];
enum object kind;
long val;
long level;
long addr;
}table[txmax+1];
char infilename[80];
FILE* infile;
// the following variables for block
long dx; // data allocation index
long lev; // current depth of block nesting
long tx; // current table index
// the following array space for interpreter
#define stacksize 50000
long s[stacksize]; // datastore
这是.c文件
// pl/0 compiler with code generation
#include <stdlib.h>
#include <string.h>
#include "pl0.h"
void error(long n)
{
long i;
printf("Error=>");
for (i = 1; i <= cc-1; i++)
{
printf(" ");
}
printf("|%s(%d)\n", err_msg[n], n);
err++;
}
void getch()
{
if(cc == ll)
{
if(feof(infile))
{
printf("************************************\n");
printf(" program incomplete\n");
printf("************************************\n");
exit(1);
}
ll = 0; cc = 0;
printf("%5d ", cx);
while((!feof(infile)) && ((ch=getc(infile))!='\n'))
{
printf("%c", ch);
ll = ll + 1;
line[ll] = ch;
}
printf("\n");
ll = ll + 1;
line[ll] = ' ';
}
cc = cc + 1;
ch = line[cc];
}
void getsym()
{
long i, j, k;
while(ch == ' ' || ch == '\t')
{
getch();
}
if(isalpha(ch)) // identified or reserved
{
k = 0;
do
{
if(k < al)
{
a[k] = ch; k = k + 1;
}
getch();
} while(isalpha(ch) || isdigit(ch));
if(k >= kk)
{
kk = k;
}
else
{
do
{
kk = kk-1; a[kk] = ' ';
} while(k < kk);
}
strcpy(id, a); i = 0; j = norw - 1;
do
{
k = (i+j)/2;
if(strcmp(id, word[k]) <= 0)
{
j = k - 1;
}
if(strcmp(id, word[k]) >=0)
{
i = k + 1;
}
} while(i <= j);
if(i-1 > j)
{
sym = wsym[k];
}
else
{
sym = ident;
}
}
else if(isdigit(ch)) // number
{
k = 0; num = 0; sym = number;
do
{
num = num * 10 + (ch - '0');
k = k + 1;
getch();
} while(isdigit(ch));
if(k > nmax)
{
error(31);
}
}
else if(ch == ':')
{
getch();
if(ch == '=')
{
sym = becomes; getch();
}
else
{
sym = nul;
}
}
else if(ch == '<')
{
getch();
if(ch == '=')
{
sym = leq; getch();
}
else if(ch == '>')
{
sym=neq; getch();
}
else
{
sym = lss;
}
}
else if(ch == '>')
{
getch();
if(ch == '=')
{
sym=geq; getch();
}
else
{
sym=gtr;
}
}
else
{
sym = ssym[(unsigned char)ch]; getch();
}
}
void gen(enum fct x, long y, long z)
{
if(cx > cxmax)
{
printf("program too long\n");
exit(1);
}
code[cx].f = x; code[cx].l = y; code[cx].a = z;
cx = cx + 1;
}
void test(unsigned long s1, unsigned long s2, long n)
{
if (!(sym & s1))
{
error(n);
s1 = s1 | s2;
while(!(sym & s1))
{
getsym();
}
}
}
void enter(enum object k) // enter object into table
{
tx = tx + 1;
strcpy(table[tx].name, id);
table[tx].kind = k;
switch(k)
{
case constant:
if(num > amax)
{
error(31);
num = 0;
}
table[tx].val = num;
break;
case variable:
table[tx].level = lev; table[tx].addr = dx; dx = dx + 1;
break;
case proc:
table[tx].level = lev;
break;
}
}
long position(char* id) // find identifier id in table
{
long i;
strcpy(table[0].name, id);
i=tx;
while(strcmp(table[i].name, id) != 0)
{
i = i - 1;
}
return i;
}
void constdeclaration()
{
if(sym == ident)
{
getsym();
if(sym == eql || sym == becomes)
{
if(sym == becomes)
{
error(1);
}
getsym();
if(sym == number)
{
enter(constant);
getsym();
}
else
{
error(2);
}
}
else
{
error(3);
}
}
else
{
error(4);
}
}
void vardeclaration()
{
if(sym == ident)
{
enter(variable);
getsym();
}
else
{
error(4);
}
}
void listcode(long cx0) // list code generated for this block
{
long i;
for(i=cx0; i<=cx-1; i++)
{
printf("%10d%5s%3d%5d\n", i, mnemonic[code[i].f], code[i].l, code[i].a);
}
}
void expression(unsigned long);
void factor(unsigned long fsys)
{
long i;
test(facbegsys, fsys, 24);
while(sym & facbegsys)
{
if(sym == ident)
{
i = position(id);
if(i==0)
{
error(11);
}
else
{
switch(table[i].kind)
{
case constant:
gen(lit, 0, table[i].val);
break;
case variable:
gen(lod, lev-table[i].level, table[i].addr);
break;
case proc:
error(21);
break;
}
}
getsym();
}
else if(sym == number)
{
if(num>amax)
{
error(31); num=0;
}
gen(lit,0,num);
getsym();
}
else if(sym == lparen)
{
getsym();
expression(rparen|fsys);
if(sym==rparen)
{
getsym();
}
else
{
error(22);
}
}
test(fsys,lparen,23);
}
}
void term(unsigned long fsys)
{
unsigned long mulop;
factor(fsys|times|slash);
while(sym==times || sym==slash)
{
mulop = sym; getsym();
factor(fsys|times|slash);
if(mulop == times)
{
gen(opr,0,4);
}
else{
gen(opr,0,5);
}
}
}
void expression(unsigned long fsys)
{
unsigned long addop;
if(sym==plus || sym==minus)
{
addop=sym; getsym();
term(fsys|plus|minus);
if(addop==minus)
{
gen(opr,0,1);
}
}
else
{
term(fsys|plus|minus);
}
while(sym==plus || sym==minus)
{
addop=sym; getsym();
term(fsys|plus|minus);
if(addop==plus)
{
gen(opr,0,2);
}
else
{
gen(opr,0,3);
}
}
}
void condition(unsigned long fsys)
{
unsigned long relop;
if(sym==oddsym)
{
getsym(); expression(fsys);
gen(opr, 0, 6);
}
else
{
expression(fsys|eql|neq|lss|gtr|leq|geq);
if(!(sym&(eql|neq|lss|gtr|leq|geq)))
{
error(20);
}
else
{
relop=sym; getsym();
expression(fsys);
switch(relop)
{
case eql:
gen(opr, 0, 8);
break;
case neq:
gen(opr, 0, 9);
break;
case lss:
gen(opr, 0, 10);
break;
case geq:
gen(opr, 0, 11);
break;
case gtr:
gen(opr, 0, 12);
break;
case leq:
gen(opr, 0, 13);
break;
}
}
}
}
void statement(unsigned long fsys)
{
long i,cx1,cx2;
if(sym==ident)
{
i=position(id);
if(i==0)
{
error(11);
}
else if(table[i].kind!=variable) // assignment to non-variable
{
error(12); i=0;
}
getsym();
if(sym==becomes)
{
getsym();
}
else
{
error(13);
}
expression(fsys);
if(i!=0)
{
gen(sto,lev-table[i].level,table[i].addr);
}
}
else if(sym==callsym)
{
getsym();
if(sym!=ident)
{
error(14);
}
else
{
i=position(id);
if(i==0)
{
error(11);
}
else if(table[i].kind==proc)
{
gen(cal,lev-table[i].level,table[i].addr);
}
else
{
error(15);
}
getsym();
}
}
else if(sym==ifsym)
{
getsym(); condition(fsys|thensym|dosym);
if(sym==thensym)
{
getsym();
}
else
{
error(16);
}
cx1=cx; gen(jpc,0,0);
statement(fsys);
code[cx1].a=cx;
}
else if(sym==beginsym)
{
getsym(); statement(fsys|semicolon|endsym);
while(sym==semicolon||(sym&statbegsys))
{
if(sym==semicolon)
{
getsym();
}
else
{
error(10);
}
statement(fsys|semicolon|endsym);
}
if(sym==endsym)
{
getsym();
}
else
{
error(17);
}
}
else if(sym==whilesym)
{
cx1=cx; getsym();
condition(fsys|dosym);
cx2=cx; gen(jpc,0,0);
if(sym==dosym)
{
getsym();
}
else
{
error(18);
}
statement(fsys); gen(jmp,0,cx1);
code[cx2].a=cx;
}
test(fsys,0,19);
}
void block(unsigned long fsys)
{
long tx0; // initial table index
long cx0; // initial code index
long tx1; // save current table index before processing nested procedures
long dx1; // save data allocation index
dx=3; tx0=tx; table[tx].addr=cx; gen(jmp,0,0);
if(lev>levmax)
{
error(32);
}
do
{
if(sym==constsym)
{
getsym();
do
{
constdeclaration();
while(sym==comma)
{
getsym(); constdeclaration();
}
if(sym==semicolon)
{
getsym();
}
else
{
error(5);
}
} while(sym==ident);
}
if(sym==varsym)
{
getsym();
do
{
vardeclaration();
while(sym==comma)
{
getsym(); vardeclaration();
}
if(sym==semicolon)
{
getsym();
}
else
{
error(5);
}
} while(sym==ident);
}
while(sym==procsym)
{
getsym();
if(sym==ident)
{
enter(proc); getsym();
}
else
{
error(4);
}
if(sym==semicolon)
{
getsym();
}
else
{
error(5);
}
lev=lev+1; tx1=tx; dx1=dx;
block(fsys|semicolon);
lev=lev-1; tx=tx1; dx=dx1;
if(sym==semicolon)
{
getsym();
test(statbegsys|ident|procsym,fsys,6);
}
else
{
error(5);
}
}
test(statbegsys|ident,declbegsys,7);
} while(sym&declbegsys);
code[table[tx0].addr].a=cx;
table[tx0].addr=cx; // start addr of code
cx0=cx; gen(Int,0,dx);
statement(fsys|semicolon|endsym);
gen(opr,0,0); // return
test(fsys,0,8);
listcode(cx0);
}
long base(long b, long l)
{
long b1;
b1=b;
while (l>0) // find base l levels down
{
b1=s[b1]; l=l-1;
}
return b1;
}
void interpret()
{
long p,b,t; // program-, base-, topstack-registers
instruction i; // instruction register
printf("start PL/0\n");
t=0; b=1; p=0;
s[1]=0; s[2]=0; s[3]=0;
do
{
i=code[p]; p=p+1;
switch(i.f)
{
case lit:
t=t+1; s[t]=i.a;
break;
case opr:
switch(i.a) // operator
{
case 0: // return
t=b-1; p=s[t+3]; b=s[t+2];
break;
case 1:
s[t]=-s[t];
break;
case 2:
t=t-1; s[t]=s[t]+s[t+1];
break;
case 3:
t=t-1; s[t]=s[t]-s[t+1];
break;
case 4:
t=t-1; s[t]=s[t]*s[t+1];
break;
case 5:
t=t-1; s[t]=s[t]/s[t+1];
break;
case 6:
s[t]=s[t]%2;
break;
case 8:
t=t-1; s[t]=(s[t]==s[t+1]);
break;
case 9:
t=t-1; s[t]=(s[t]!=s[t+1]);
break;
case 10:
t=t-1; s[t]=(s[t]<s[t+1]);
break;
case 11:
t=t-1; s[t]=(s[t]>=s[t+1]);
break;
case 12:
t=t-1; s[t]=(s[t]>s[t+1]);
break;
case 13:
t=t-1; s[t]=(s[t]<=s[t+1]);
}
break;
case lod:
t=t+1; s[t]=s[base(b,i.l)+i.a];
break;
case sto:
s[base(b,i.l)+i.a]=s[t]; printf("%10d\n", s[t]); t=t-1;
break;
case cal: // generate new block mark
s[t+1]=base(b,i.l); s[t+2]=b; s[t+3]=p;
b=t+1; p=i.a;
break;
case Int:
t=t+i.a;
break;
case jmp:
p=i.a;
break;
case jpc:
if(s[t]==0)
{
p=i.a;
}
t=t-1;
}
} while(p!=0);
printf("end PL/0\n");
}
int main()
{
long i;
for(i=0; i<256; i++)
{
ssym[i]=nul;
}
strcpy(word[0], "begin ");
strcpy(word[1], "call ");
strcpy(word[2], "const ");
strcpy(word[3], "do ");
strcpy(word[4], "end ");
strcpy(word[5], "if ");
strcpy(word[6], "odd ");
strcpy(word[7], "procedure ");
strcpy(word[8], "then ");
strcpy(word[9], "var ");
strcpy(word[10], "while ");
wsym[0]=beginsym;
wsym[1]=callsym;
wsym[2]=constsym;
wsym[3]=dosym;
wsym[4]=endsym;
wsym[5]=ifsym;
wsym[6]=oddsym;
wsym[7]=procsym;
wsym[8]=thensym;
wsym[9]=varsym;
wsym[10]=whilesym;
ssym['+']=plus;
ssym['-']=minus;
ssym['*']=times;
ssym['/']=slash;
ssym['(']=lparen;
ssym[')']=rparen;
ssym['=']=eql;
ssym[',']=comma;
ssym['.']=period;
ssym[';']=semicolon;
strcpy(mnemonic[lit],"LIT");
strcpy(mnemonic[opr],"OPR");
strcpy(mnemonic[lod],"LOD");
strcpy(mnemonic[sto],"STO");
strcpy(mnemonic[cal],"CAL");
strcpy(mnemonic[Int],"INT");
strcpy(mnemonic[jmp],"JMP");
strcpy(mnemonic[jpc],"JPC");
declbegsys=constsym|varsym|procsym;
statbegsys=beginsym|callsym|ifsym|whilesym;
facbegsys=ident|number|lparen;
printf("please input source program file name: ");
scanf("%s",infilename);
printf("\n");
if((infile=fopen(infilename,"r"))==NULL)
{
printf("File %s can't be opened.\n", infilename);
exit(1);
}
err=0;
cc=0; cx=0; ll=0; ch=' '; kk=al; getsym();
lev=0; tx=0;
block(declbegsys|statbegsys|period);
if(sym!=period)
{
error(9);
}
if(err==0)
{
// interpret();
}
else
{
printf("errors in PL/0 program\n");
}
fclose(infile);
return (0);
}
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