feat: open and load file into memory

docs/todos.md

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+# Todos
+
+- [x] How to capture arguments passed to a C program
+    
+      ```c
+      // argc is the number of args passed
+      // argc is always 1 or more
+      // argc always has name/path of program as first arg
+      int main(int argc, char *argv[]) {
+      // do stuff with the args
+      }
+      ```
+- [x] How to print argument value
+      
+      ```
+      printf("%s", argv[1]);
+      ```
+
+- [x] Read a file
+    
+      ```c
+      // open file in read mode. returns NULL if doesn't exist
+      FILE *file_ptr = fread(file_path, "r");
+      
+      // seeking to end of file.
+      // useful telling number of bytes
+      fseek(file_ptr, 0, SEEK_END);
+
+      // get number of bytes
+      int num_of_bytes = ftell(file_ptr);
+      
+      // seek to begin of file
+      fseek(file_ptr, 0, SEEK_SET);
+      ```
+
+- [x] Store contents of file in memory
+- [x] Print file contents
+- [x] Print instructions
+- [x] Make sure program occupies correct space in chip memory
+- [ ] Parse individual instructions from binary CHIP-8 file

main.c

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+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+#define MEMORY_SIZE 4096
+#define PROGRAM_START 512
+
+enum ExitCodes {
+  COMPLETED_SUCCESSFULLY,
+  FILE_NOT_PROVIDED,
+  FILE_MISSING,
+  PROGRAM_TOO_LARGE,
+  MEMORY_ALLOCATION_FAILURE,
+};
+
+// TODO: Add additional members
+// i.e. registers
+typedef struct ChipEight {
+  uint8_t memory[MEMORY_SIZE] ;
+} chip_eight_t;
+
+void println(const char *format, ...) {
+  va_list args;
+
+  va_start(args, format);
+
+  vprintf(format, args);
+
+  va_end(args);
+
+  printf("\n");
+}
+
+int main(int argc, char *argv[]) {
+  if (argc < 2) {
+    println("You fucked up bro! We need a file to load into memory.");
+    println("Usage: chip.exe <file-to-load>");
+    return FILE_NOT_PROVIDED;
+  }
+
+  char* file_path = argv[1];
+  println("Loading file at %s...", file_path);
+
+  FILE *file_ptr = fopen(file_path, "rb");
+
+  if (file_ptr == NULL) {
+    println("File '%s' does not exist.", file_path);
+    return FILE_MISSING;
+  }
+
+  fseek(file_ptr, 0, SEEK_END);
+  int num_of_bytes = ftell(file_ptr);
+
+  int max_program_size = MEMORY_SIZE - PROGRAM_START;
+
+  if (num_of_bytes > max_program_size) {
+    println("File at '%s' exceeds max program size of %d", file_path, max_program_size);
+    return PROGRAM_TOO_LARGE;
+  }
+
+  fseek(file_ptr, 0, SEEK_SET);
+
+  chip_eight_t *chip = malloc(sizeof(chip_eight_t));
+
+  if (chip == NULL) {
+    println("Failed to allocate memory for chip.");
+    return MEMORY_ALLOCATION_FAILURE;
+  }
+
+  fread(&chip->memory[PROGRAM_START], sizeof(uint8_t), num_of_bytes, file_ptr);
+
+  println("File '%s' loaded successfully", file_path);
+
+  fclose(file_ptr);
+
+  // TODO: Parse instructions
+  println("INSTRUCTIONS:");
+
+  for (int i = 0; i < MEMORY_SIZE; i++) {
+    println("%d: %x ", i, chip->memory[i]);
+  }
+
+  free(chip);
+
+  return COMPLETED_SUCCESSFULLY;
+}
+

run.ps1

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+Write-Host "[Compiling...]"
+
+gcc main.c -o ./.bin/chip.exe
+
+if ($LASTEXITCODE -ne 0) {
+  Write-Host "[Failed to compiled]";
+  exit 1;
+}
+
+Write-Host "[Compiled successfully]";
+
+Write-Host "[Running..]"
+Write-Host "`n"
+
+./.bin/chip.exe $args[0]