104 lines
2.2 KiB
C
104 lines
2.2 KiB
C
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/*
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* Instruction-level simulator for the LC
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#define NUMMEMORY 65536 /* maximum number of words in memory */
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#define NUMREGS 8 /* number of machine registers */
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#define MAXLINELENGTH 1000
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#define ADD 0
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#define NAND 1
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#define LW 2
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#define SW 3
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#define BEQ 4
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#define JALR 5
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#define HALT 6
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#define NOOP 7
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typedef struct stateStruct {
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int pc;
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int mem[NUMMEMORY];
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int reg[NUMREGS];
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int numMemory;
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} stateType;
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void printState(stateType *);
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void run(stateType);
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int convertNum(int);
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int
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main(int argc, char *argv[])
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{
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int i;
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char line[MAXLINELENGTH];
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stateType state;
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FILE *filePtr;
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if (argc != 2) {
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printf("error: usage: %s <machine-code file>\n", argv[0]);
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exit(1);
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}
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/* initialize memories and registers */
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for (i=0; i<NUMMEMORY; i++) {
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state.mem[i] = 0;
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}
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for (i=0; i<NUMREGS; i++) {
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state.reg[i] = 0;
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}
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state.pc=0;
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/* read machine-code file into instruction/data memory (starting at
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address 0) */
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filePtr = fopen(argv[1], "r");
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if (filePtr == NULL) {
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printf("error: can't open file %s\n", argv[1]);
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perror("fopen");
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exit(1);
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}
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for (state.numMemory=0; fgets(line, MAXLINELENGTH, filePtr) != NULL;
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state.numMemory++) {
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if (state.numMemory >= NUMMEMORY) {
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printf("exceeded memory size\n");
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exit(1);
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}
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if (sscanf(line, "%d", state.mem+state.numMemory) != 1) {
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printf("error in reading address %d\n", state.numMemory);
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exit(1);
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}
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printf("memory[%d]=%d\n", state.numMemory, state.mem[state.numMemory]);
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}
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printf("\n");
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/* run never returns */
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run(state);
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return(0);
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}
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void
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run(stateType state)
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{
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int arg0, arg1, arg2, addressField;
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int instructions=0;
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int opcode;
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int maxMem=-1; /* highest memory address touched during run */
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for (; 1; instructions++) { /* infinite loop, exits when it executes halt */
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printState(&state);
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if (state.pc < 0 || state.pc >= NUMMEMORY) {
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printf("pc went out of the memory range\n");
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exit(1);
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}
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maxMem = (state.pc > maxMem)?state.pc:maxMem;
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