/****************************************************/
/* File: tm.c */
/* The TM ("Tiny Machine") computer */
/* Compiler Construction: Principles and Practice */
/* Kenneth C. Louden */
/****************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#ifndef TRUE
#define TRUE 1
#endif
#ifndef FALSE
#define FALSE 0
#endif
/******* const *******/
#define IADDR_SIZE 1024 /* increase for large programs */
#define DADDR_SIZE 1024 /* increase for large programs */
#define NO_REGS 8
#define PC_REG 7
#define LINESIZE 121
#define WORDSIZE 20
/******* type *******/
typedef enum {
opclRR, /* reg operands r,s,t */
opclRM, /* reg r, mem d+s */
opclRA /* reg r, int d+s */
} OPCLASS;
typedef enum {
/* RR instructions */
opHALT, /* RR halt, operands are ignored */
opIN, /* RR read into reg(r); s and t are ignored */
opOUT, /* RR write from reg(r), s and t are ignored */
opADD, /* RR reg(r) = reg(s)+reg(t) */
opSUB, /* RR reg(r) = reg(s)-reg(t) */
opMUL, /* RR reg(r) = reg(s)*reg(t) */
opDIV, /* RR reg(r) = reg(s)/reg(t) */
opRRLim, /* limit of RR opcodes */
/* RM instructions */
opLD, /* RM reg(r) = mem(d+reg(s)) */
opST, /* RM mem(d+reg(s)) = reg(r) */
opRMLim, /* Limit of RM opcodes */
/* RA instructions */
opLDA, /* RA reg(r) = d+reg(s) */
opLDC, /* RA reg(r) = d ; reg(s) is ignored */
opJLT, /* RA if reg(r)<0 then reg(7) = d+reg(s) */
opJLE, /* RA if reg(r)<=0 then reg(7) = d+reg(s) */
opJGT, /* RA if reg(r)>0 then reg(7) = d+reg(s) */
opJGE, /* RA if reg(r)>=0 then reg(7) = d+reg(s) */
opJEQ, /* RA if reg(r)==0 then reg(7) = d+reg(s) */
opJNE, /* RA if reg(r)!=0 then reg(7) = d+reg(s) */
opRALim /* Limit of RA opcodes */
} OPCODE;
typedef enum {
srOKAY,
srHALT,
srIMEM_ERR,
srDMEM_ERR,
srZERODIVIDE
} STEPRESULT;
typedef struct {
int iop ;
int iarg1 ;
int iarg2 ;
int iarg3 ;
} INSTRUCTION;
/******** vars ********/
int iloc = 0 ;
int dloc = 0 ;
int traceflag = FALSE;
int icountflag = FALSE;
INSTRUCTION iMem [IADDR_SIZE];
int dMem [DADDR_SIZE];
int reg [NO_REGS];
char * opCodeTab[]
= {"HALT","IN","OUT","ADD","SUB","MUL","DIV","????",
/* RR opcodes */
"LD","ST","????", /* RM opcodes */
"LDA","LDC","JLT","JLE","JGT","JGE","JEQ","JNE","????"
/* RA opcodes */
};
char * stepResultTab[]
= {"OK","Halted","Instruction Memory Fault",
"Data Memory Fault","Division by 0"
};
char pgmName[20];
FILE *pgm ;
char in_Line[LINESIZE] ;
int lineLen ;
int inCol ;
int num ;
char word[WORDSIZE] ;
char ch ;
int done ;
/********************************************/
int opClass( int c )
{ if ( c <= opRRLim) return ( opclRR );
else if ( c <= opRMLim) return ( opclRM );
else return ( opclRA );
} /* opClass */
/********************************************/
void writeInstruction ( int loc )
{ printf( "%5d: ", loc) ;
if ( (loc >= 0) && (loc < IADDR_SIZE) )
{ printf("%6s%3d,", opCodeTab[iMem[loc].iop], iMem[loc].iarg1);
switch ( opClass(iMem[loc].iop) )
{ case opclRR: printf("%1d,%1d", iMem[loc].iarg2, iMem[loc].iarg3);
break;
case opclRM:
case opclRA: printf("%3d(%1d)", iMem[loc].iarg2, iMem[loc].iarg3);
break;
}
printf ("\n") ;
}
} /* writeInstruction */
/********************************************/
void getCh (void)
{ if (++inCol < lineLen)
ch = in_Line[inCol] ;
else ch = ' ' ;
} /* getCh */
/********************************************/
int nonBlank (void)
{ while ((inCol < lineLen)
&& (in_Line[inCol] == ' ') )
inCol++ ;
if (inCol < lineLen)
{ ch = in_Line[inCol] ;
return TRUE ; }
else
{ ch = ' ' ;
return FALSE ; }
} /* nonBlank */
/********************************************/
int getNum (void)
{ int sign;
int term;
int temp = FALSE;
num = 0 ;
do
{ sign = 1;
while ( nonBlank() && ((ch == '+') || (ch == '-')) )
{ temp = FALSE ;
if (ch == '-') sign = - sign ;
getCh();
}
term = 0 ;
nonBlank();
while (isdigit(ch))
{ temp = TRUE ;
term = term * 10 + ( ch - '0' ) ;
getCh();
}
num = num + (term * sign) ;
} while ( (nonBlank()) && ((ch == '+') || (ch == '-')) ) ;
return temp;
} /* getNum */
/********************************************/
int getWord (void)
{ int temp = FALSE;
int length = 0;
if (nonBlank ())
{ while (isalnum(ch))
{ if (length < WORDSIZE-1) word [length++] = ch ;
getCh() ;
}
word[length] = '\0';
temp = (length != 0);
}
return temp;
} /* getWord */
/********************************************/
int skipCh ( char c )
{ int temp = FALSE;
if ( nonBlank() && (ch == c) )
{ getCh();
temp = TRUE;
}
return temp;
} /* skipCh */
/********************************************/
int atEOL(void)
{ return ( ! nonBlank ());
} /* atEOL */
/********************************************/
int error( char * msg, int lineNo, int instNo)
{ printf("Line %d",lineNo);
if (instNo >= 0) printf(" (Instruction %d)",instNo);
printf(" %s\n",msg);
return FALSE;
} /* error */
/********************************************/
int readInstructions (void)
{ OPCODE op;
int arg1, arg2, arg3;
int loc, regNo, lineNo;
for (regNo = 0 ; regNo < NO_REGS ; regNo++)
reg[regNo] = 0 ;
dMem[0] = DADDR_SIZE - 1 ;
for (loc = 1 ; loc < DADDR_SIZE ; loc++)
dMem[loc] = 0 ;
for (loc = 0 ; loc < IADDR_SIZE ; loc++)
{ iMem[loc].iop = opHALT ;
iMem[loc].iarg1 = 0 ;
iMem[loc].iarg2 = 0 ;
iMem[loc].iarg3 = 0 ;
}
lineNo = 0 ;
while (! feof(pgm))
{ fgets( in_Line, LINESIZE-2, pgm ) ;
inCol = 0 ;
lineNo++;
lineLen = strlen(in_Line)-1 ;
if (in_Line[lineLen]=='\n') in_Line[lineLen] = '\0' ;
else in_Line[++lineLen] = '\0';
if ( (nonBlank()) && (in_Line[inCol] != '*') )
{ if (! getNum())
return error("Bad location", lineNo,-1);
loc = num;
if (loc > IADDR_SIZE)
return error("Location too large",lineNo,loc);
if (! skipCh(':'))
return error("Missing colon", lineNo,loc);
if (! getWord ())
return error("Missing opcode", lineNo,loc);
op = opHALT ;
while ((op < opRALim)
&& (strncmp(opCodeTab[op], word, 4) != 0) )
op++ ;
if (strncmp(opCodeTab[op], word, 4) != 0)
return error("Illegal opcode", lineNo,loc);
switch ( opClass(op) )
{ case opclRR :
/***********************************/
if ( (! getNum ()) || (num < 0) || (num >= NO_REGS) )
return error("Bad first register", lineNo,loc);
arg1 = num;
if ( ! skipCh(','))
return error("Missing comma", lineNo, loc);
if ( (! getNum ()) || (num < 0) || (num >= NO_REGS) )
return error("Bad second register", lineNo, loc);
arg2 = num;
if ( ! skipCh(','))
return error("Missing comma", lineNo,loc);
if ( (! getNum ()) || (num < 0) || (num >= NO_REGS) )
return error("Bad third register", lineNo,loc);
arg3 = num;
break;
case opclRM :
case opclRA :
/***********************************/
if ( (! getNum ()) || (num < 0) || (num >= NO_REGS) )
return error("B
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