Updated repository
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Veit Heller
284
src/vm.c
Normal file
284
src/vm.c
Normal file
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#include "vm.h"
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/**
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* @brief disassemble
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* @param sp -> stack pointer
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* @param fp -> function pointer
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* @param ip -> instruction pointer
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* @param opcode -> current opcode
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* @param ins -> instruction struct
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* @param code -> opcodes
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* @param stack -> stack
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*
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* prints current operations and a stack trace.
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* Is invoked if DEBUG is defined.
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*/
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static inline void disassemble(int sp, int fp, int ip, int opcode, instruction* ins, int code[], int stack[]){
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int i;
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if(opcode > 0 && opcode < 24)
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printf("%04d: %s(%d)\n", ip, ins[opcode].name, opcode);
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if(ins[opcode].operands == 1)
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printf("\t%d\n", code[ip+1]);
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else if(ins[opcode].operands == 2)
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printf("\t%d, %d\n", code[ip+1], code[ip+2]);
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printf("\n===Stack trace===\n");
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for(i = sp; i >= 0; i--)
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printf("%04d: %d\n", i, stack[i]);
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printf("\n");
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}
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void vm_execute(int code[], int ip, int datasize, unsigned long length){
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int* data = (int *) alloca((size_t)datasize * sizeof(int));
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int stack[MAX_SIZE];
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register int sp = -1;
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register int fp = -1;
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int nargs, addr, a, b;
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instruction* ins = setup_instructions();
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while(ip < length){
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int opcode = code[ip];
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ip++;
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if(DEBUG){
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if(ip+2 != length)
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disassemble(sp, fp, ip, opcode, ins, code, stack);
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}
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switch(opcode){
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case IINC:
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stack[sp]++;
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break;
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case IDEC:
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stack[sp]--;
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break;
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case LOAD:
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stack[++sp] = stack[code[ip++]+fp];
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break;
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case STORE:
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stack[fp+code[ip++]] = stack[sp--];
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case BR:
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ip = code[ip];
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break;
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case BRT:
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addr = code[ip++];
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if(stack[sp--] == TRUE) ip = addr;
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break;
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case BRF:
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addr = code[ip++];
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if(stack[sp--] == FALSE) ip = addr;
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break;
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case IADD:
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b = stack[sp--];
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a = stack[sp--];
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stack[++sp] = a + b;
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break;
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case ISUB:
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b = stack[sp--];
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a = stack[sp--];
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stack[++sp] = a - b;
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break;
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case IMULT:
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b = stack[sp--];
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a = stack[sp--];
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stack[++sp] = a * b;
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break;
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case IDIV:
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b = stack[sp--];
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a = stack[sp--];
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stack[++sp] = a / b;
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break;
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case IMOD:
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b = stack[sp--];
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a = stack[sp--];
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stack[++sp] = a % b;
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break;
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case ILT:
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b = stack[sp--];
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a = stack[sp--];
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stack[++sp] = a < b ? TRUE : FALSE;
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break;
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case IEQ:
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b = stack[sp--];
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a = stack[sp--];
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stack[++sp] = a == b;
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break;
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case IGT:
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b = stack[sp--];
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a = stack[sp--];
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stack[++sp] = a > b ? TRUE : FALSE;
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break;
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case ILEQ:
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b = stack[sp--];
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a = stack[sp--];
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stack[++sp] = a <= b ? TRUE : FALSE;
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break;
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case IGEQ:
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b = stack[sp--];
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a = stack[sp--];
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stack[++sp] = a >= b ? TRUE : FALSE;
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break;
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case ICONST:
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stack[++sp] = code[ip++];
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break;
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case GLOAD:
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stack[++sp] = data[code[ip++]];
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break;
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case GSTORE:
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data[code[ip++]] = stack[sp--];
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break;
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case IPRINT:
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printf("%d", stack[sp--]);
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break;
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case PRINT:
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putchar(stack[sp--]);
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break;
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case FETCH:
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stack[++sp] = getchar();
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break;
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case HALT:
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return;
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case CALL:
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addr = code[ip++];
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nargs = code[ip++];
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stack[++sp] = nargs;
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stack[++sp] = fp;
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stack[++sp] = ip;
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fp = sp;
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ip = addr;
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break;
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case RET:
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addr = stack[sp--];
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sp = fp;
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ip = stack[sp--];
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fp = stack[sp--];
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nargs = stack[sp--];
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sp -= nargs;
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stack[++sp] = addr;
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break;
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case POP:
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sp--;
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default:
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fprintf(stderr, "Unrecognized: %d\n", opcode);
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die(127, "Exit on program failure.");
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}
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}
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return;
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}
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program vm_compile(char *filename){
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FILE* file = fopen(filename, "r");
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char* line = NULL;
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char** command = NULL;
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unsigned long size = 100;
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int* code = malloc(size * sizeof(int));
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unsigned long codep = 0;
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register int i;
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instruction* ins = setup_instructions();
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unsigned int len = IDEC;
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size_t linelength = 0;
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int entry = 0;
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program prog;
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if(!file)
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die(127, "Could not open file.");
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while(getline(&line, &linelength, file) != -1){
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short found = FALSE;
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unsigned int elemc = 0;
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strtok(line, "\n");
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command = str_split(line, ' ', &elemc);
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if(codep == size){
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size += 100;
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code = (int *) realloc(code, size * sizeof(int));
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if(code == NULL)
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die(127, "Program too big, could not allocate enough storage.");
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}
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if(strcmp(command[0], "ENTRY") == 0){
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entry = (int) strtol(command[1], (char **) NULL, 10);
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}else{
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if(strcmp("\n", command[0]) == 0)
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continue;
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for(i = 1; i < len; i++)
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if(strcmp(ins[i].name, command[0]) == 0){
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code[codep++] = i;
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found = TRUE;
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break;
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}
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if(found == FALSE){
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fprintf(stderr,
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"Line %s called with unknown command: %s\n",
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line, command[0]);
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die(127, "Compilation failed.");
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}
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if(ins[i].operands > 0){
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int nargs = ins[i].operands;
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if(nargs != elemc-1){
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fprintf(stderr,
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"Line %s called with wrong number of arguments (got %d, expected %d)\n",
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line, elemc-1, nargs);
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die(127, "Compilation failed.");
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}
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for(i = 1; i <= nargs; i++){
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code[codep++] = (int) strtol(command[i], (char **) NULL, 10);
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}
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}
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}
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}
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fclose(file);
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if(line)
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free(line);
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code = (int *) realloc(code, codep * sizeof(int));
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prog.length = codep;
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prog.entrypoint = entry;
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prog.code = code;
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if(command != NULL)
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free(command);
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return prog;
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}
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char** str_split(char* a_str, const char a_delim, unsigned int* elemc){
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char** result = 0;
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char* tmp = a_str;
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char* last_comma = 0;
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char delim[2];
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delim[0] = a_delim;
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delim[1] = 0;
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while (*tmp){
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if (a_delim == *tmp){
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(*elemc)++;
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last_comma = tmp;
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}
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tmp++;
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}
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*elemc += last_comma < (a_str + strlen(a_str) - 1);
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(*elemc)++;
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result = malloc(sizeof(char*) * *elemc);
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if (result){
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size_t idx = 0;
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char* token = strtok(a_str, delim);
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while (token){
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assert(idx < *elemc);
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*(result + idx++) = strdup(token);
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token = strtok(0, delim);
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}
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assert(idx == *elemc - 1);
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*(result + idx) = 0;
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}
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(*elemc)--;
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return result;
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}
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