lifeboot.asm: add xorshift

[lifeboot.git] / prototype.c

diff --git a/prototype.c b/prototype.c
index c9c2afa8796467d30fceb93c72d64b402d1c2e06..83b93989a1d44687b8990c50f185cc445ff64ef3 100644 (file)
--- a/prototype.c
+++ b/prototype.c
@@ -1,6 +1,5 @@
+#include <stdint.h>

 #include <stdio.h>
 #include <stdio.h>

-#include <stdlib.h>
-#include <unistd.h>

 #include <string.h>
 #include <time.h>
 
 #include <string.h>
 #include <time.h>
 


@@ -12,63 +11,91 @@
 
 #define INIT_RATIO 4
 
 
 #define INIT_RATIO 4
 

-#define STR(x) _STR(x)
+#define STR(x) _STR (x)

 #define _STR(x) #x
 
 #define _STR(x) #x
 

-static void clearscr() {
-  printf("\e[1;1H\e[2J");
+static uint16_t xss; /* xs() state */
+
+static uint16_t
+xs () /* xorshift prng */
+{
+  xss ^= (xss << 1);
+  xss ^= (xss >> 3);
+  xss ^= (xss << 10);
+
+  return xss;
+}
+
+static void
+clearscr ()
+{
+  printf ("\e[1;1H\e[2J");

 }
 
 }
 

-static void print_row(char row[COLS]) {
-  printf("%." STR(COLS) "s\n", row);
+static void
+print_row (char row[COLS])
+{
+  printf ("%." STR (COLS) "s\n", row);

 }
 
 }
 

-static void print_grid(char grid[COLS * ROWS]) {
+static void
+print_grid (char grid[COLS * ROWS])
+{

   for (int i = 0; i < ROWS; i++)
   for (int i = 0; i < ROWS; i++)

-    print_row(grid + i * COLS);
+    print_row (grid + i * COLS);

 }
 
 }
 

-static void init_grid(char grid[COLS * ROWS]) {
-  for (int i = 0; i < COLS * ROWS; i++) {
-    if (rand() % INIT_RATIO)
-      grid[i] = DEAD;
-    else
-      grid[i] = ALIVE;
-  }
+static void
+init_grid (char grid[COLS * ROWS])
+{
+  for (int i = 0; i < COLS * ROWS; i++)
+    {
+      if (xs () % INIT_RATIO)
+        grid[i] = DEAD;
+      else
+        grid[i] = ALIVE;
+    }

 }
 
 }
 

-static char get_state(char grid[COLS * ROWS], int row, int col) {
+static char
+get_state (char grid[COLS * ROWS], int row, int col)
+{

   if (row < 0 || row >= ROWS || col < 0 || col >= COLS)
     return DEAD;
 
   return grid[row * COLS + col];
 }
 
   if (row < 0 || row >= ROWS || col < 0 || col >= COLS)
     return DEAD;
 
   return grid[row * COLS + col];
 }
 

-static int alive_neighbours(char grid[COLS * ROWS], int idx) {
+static int
+alive_neighbours (char grid[COLS * ROWS], int idx)
+{

   int row = idx / COLS;
   int col = idx % COLS;
   int neighbours = 0;
 
   for (int i = -1; i <= 1; i++)
     for (int j = -1; j <= 1; j++)
   int row = idx / COLS;
   int col = idx % COLS;
   int neighbours = 0;
 
   for (int i = -1; i <= 1; i++)
     for (int j = -1; j <= 1; j++)

-      if (get_state(grid, row + i, col + j) == ALIVE)
+      if (get_state (grid, row + i, col + j) == ALIVE)

         neighbours++;
 
         neighbours++;
 

-  if (get_state(grid, row, col) == ALIVE)
+  if (get_state (grid, row, col) == ALIVE)

     neighbours--;
 
   return neighbours;
 }
 
     neighbours--;
 
   return neighbours;
 }
 

-static char next_state(char grid[COLS * ROWS], int idx) {
-  int n = alive_neighbours(grid, idx);
+static char
+next_state (char grid[COLS * ROWS], int idx)
+{
+  int n = alive_neighbours (grid, idx);

 
 

-  if (get_state(grid, idx / COLS, idx % COLS) == ALIVE) {
-    if (n < 2 || n > 3)
-      return DEAD;
+  if (get_state (grid, idx / COLS, idx % COLS) == ALIVE)
+    {
+      if (n < 2 || n > 3)
+        return DEAD;

 
 

-    return ALIVE;
-  }
+      return ALIVE;
+    }

 
   if (n == 3)
     return ALIVE;
 
   if (n == 3)
     return ALIVE;


@@ -76,26 +103,32 @@ static char next_state(char grid[COLS * ROWS], int idx) {
   return DEAD;
 }
 
   return DEAD;
 }
 

-static void update_grid(char grid[COLS * ROWS]) {
+static void
+update_grid (char grid[COLS * ROWS])
+{

   char new[COLS * ROWS];
 
   for (int i = 0; i < COLS * ROWS; i++)
   char new[COLS * ROWS];
 
   for (int i = 0; i < COLS * ROWS; i++)

-    new[i] = next_state(grid, i);
+    new[i] = next_state (grid, i);

 
 

-  memcpy(grid, new, COLS * ROWS);
+  memcpy (grid, new, COLS * ROWS);

 }
 
 }
 

-int main () {
+int
+main ()
+{

   char grid[COLS * ROWS];
 
   char grid[COLS * ROWS];
 

-  srand(time(0));
-  init_grid(grid);
+  xss = time (0);
+  init_grid (grid);

 
 

-  do {
-    clearscr();
-    print_grid(grid);
-    update_grid(grid);
-  } while (getchar() != 'q');
+  do
+    {
+      clearscr ();
+      print_grid (grid);
+      update_grid (grid);
+    }
+  while (getchar () != 'q');

 
   return 0;
 }
 
   return 0;
 }