feat: implemented parsing opcodes and dumping to csv

main.c

@@ -2,9 +2,22 @@
 #include <stdarg.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include <sys/time.h>
+#include <windows.h>
+#include <signal.h>
 
 #define MEMORY_SIZE 4096
 #define PROGRAM_START 512
+#define CPU_CLOCK_HZ 600
+#define TIMER_HZ 60
+
+const int CYCLES_PER_FRAME = CPU_CLOCK_HZ / TIMER_HZ;
+
+volatile sig_atomic_t keep_running = 1;
+
+void handle_sigint() {
+  keep_running = 0;
+}
 
 enum ExitCodes {
   COMPLETED_SUCCESSFULLY,
@@ -18,6 +31,9 @@ enum ExitCodes {
 // i.e. registers
 typedef struct ChipEight {
   uint8_t memory[MEMORY_SIZE];
+  uint16_t pc;
+  uint8_t dt;
+  uint8_t st;
 } chip_eight_t;
 
 void println(const char *format, ...) {
@@ -32,13 +48,30 @@ void println(const char *format, ...) {
   printf("\n");
 }
 
+long get_time() {
+  struct timeval tv;
+
+  gettimeofday(&tv, NULL);
+
+  const int ms_per_sec = 1000;
+  long ms = tv.tv_sec / ms_per_sec;
+
+  return ms;
+}
+
 int main(int argc, char *argv[]) {
+  // Sets up Ctrl+C handling
+  signal(SIGINT, handle_sigint);
+  signal(SIGTERM, handle_sigint);
+
+  // Validate file argument
   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;
   }
 
+  // Load file
   char* file_path = argv[1];
   println("Loading file at %s...", file_path);
 
@@ -56,6 +89,7 @@ int main(int argc, char *argv[]) {
 
   if (num_of_bytes > max_program_size) {
     println("File at '%s' exceeds max program size of %d", file_path, max_program_size);
+    fclose(file_ptr);
     return PROGRAM_TOO_LARGE;
   }
 
@@ -65,22 +99,135 @@ int main(int argc, char *argv[]) {
 
   if (chip == NULL) {
     println("Failed to allocate memory for chip.");
+    fclose(file_ptr);
     return MEMORY_ALLOCATION_FAILURE;
   }
 
   fread(&chip->memory[PROGRAM_START], sizeof(uint8_t), num_of_bytes, file_ptr);
   
+  chip->pc = PROGRAM_START;
+  chip->dt = 0;
+  chip->st = 0;
+
   println("File '%s' loaded successfully", file_path);
 
   fclose(file_ptr);
 
-  // TODO: Parse instructions
+  FILE *csv_file_ptr = fopen("./imb_logo_opcodes.csv", "a");
-  println("INSTRUCTIONS:");
 
-  for (int i = 0; i < MEMORY_SIZE; i++) {
+  if (csv_file_ptr == NULL) {
-    println("%d: %x ", i, chip->memory[i]);
+    println("Failed to open csv file for writing");
+    return -1;
   }
 
+  char *csv_headers = "opcode,nnn,n,x,y,kk\n";
+  fprintf(csv_file_ptr, csv_headers);
+
+  // main loop
+  while(keep_running) {
+    if (chip->pc > MEMORY_SIZE) {
+      break;
+    }
+
+    long frame_start = get_time();
+
+    for(int i = 0; i < CYCLES_PER_FRAME; i++) {
+
+      // we need to read 2 bytes at at time:
+      // i.e. 00000000 00000000
+      // byte 1: 00011000 
+      // shift:  00011000 00000000
+      // byte 2:          11100110
+      // combine: |       11100110
+      //
+      // result: 00011000 11100110
+      uint16_t opcode = (chip->memory[chip->pc] << 8) | (chip->memory[chip->pc + 1]);
+      chip->pc += 2;
+      
+      // nnn or addr - A 12-bit value, the lowest 12 bits of the instruction
+      // i.e. 00001111 11111111
+      // value:  11001111 11001100 (53196)
+      // oper:   &
+      // mask:   0000111111111111  (4095)
+      // result: 00001111 11001100 (4044)
+      uint16_t nnn = opcode & 4095;
+
+      // n or nibble - A 4-bit value, the lowest 4 bits of the instruction
+      // i.e. 00000000 00001111
+      // value:  11001111 11001100 (53196)
+      // oper: &
+      // mask: 00000000 00001111 (15)
+      uint16_t n = opcode & 15;
+
+      // x - A 4-bit value, the lower 4 bits of the high byte of the instruction
+      // i.e. 00001111 00000000
+      // oper: >> 8
+      // oper: &
+      // mask: 00001111 00000000 (3840)
+      uint16_t x = (opcode >> 8) & 3840;
+
+      // y - A 4-bit value, the upper 4 bits of the low byte of the instruction
+      // i.e. 00000000 11110000
+      // oper: >> 4 
+      // oper: &
+      // mask: 00000000 11110000 (240)
+      uint16_t y = (opcode >> 4) & 240;
+      
+      // kk or byte - An 8-bit value, the lowest 8 bits of the instruction
+      // i.e. 00000000 11111111
+      // oper: &
+      // mask: 00000000 11111111 (255)
+      uint16_t kk = opcode & 255;
+
+      // write headers of variable name to .csv file
+      // create a string for each opcode that is comma separated
+      // then write that string into a .csv file
+      
+      char *csv_format = "%x,%d,%d,%d,%d,%d\n";
+      int len_of_str = snprintf(NULL, 0, csv_format, opcode, nnn, n, x, y, kk);
+      char *csv_str = malloc((len_of_str + 1) * sizeof(char));
+
+      if (csv_str == NULL) {
+        println("Failed to allocate memory for csv string");
+        return -1;
+      }
+      
+      snprintf(csv_str, len_of_str + 1, csv_format, opcode, nnn, n, x, y, kk);
+      fprintf(csv_file_ptr, csv_str);
+
+      free(csv_str);
+      csv_str = NULL;
+
+      println("opcode: %d", opcode);
+      println("nnn   : %d", nnn);
+      println("n     : %d", n);
+      println("x     : %d", x);
+      println("y     : %d", y);
+      println("kk    : %d", kk);
+    }
+
+    if (chip->dt > 0) {
+      chip->dt--;
+    }
+
+    if (chip->st > 0) {
+      chip->st++;
+      // TODO: Play sound
+    } else {
+      // TODO: Play sound
+    }
+    
+    float min_diff = 16.66;
+    long frame_end = get_time();
+    long diff = frame_end - frame_start;
+
+    if (diff < min_diff) {
+      Sleep(min_diff - diff);
+    }
+  }
+
+  fclose(csv_file_ptr);
+
   free(chip);
 
   return COMPLETED_SUCCESSFULLY;