report number of free pages

src/kernel/main.c

@@ -21,6 +21,7 @@ OF THIS SOFTWARE.
 #include "files.h"
 #include "mem.h"
 #include "proc.h"
+#include "misc.h"
 
 void main(void) {
   *(uint32_t *)0x0000050c = (uint32_t)allocate_pages(16 * sizeof(struct file_handle_info), 2);
@@ -31,6 +32,21 @@ void main(void) {
   for (struct proc_info *i = FILE_HANDLES, *l = FILE_HANDLES + 65536; i < l; ++i)
     i->memory_start = 0;
 
+  uint16_t pages_free = 0, pages_total = 0;
+  for (uint16_t *i = MMAP; i < MMAP + 0x1000; ++i)
+    switch (*i) {
+    case 1:
+      continue;
+    case 0:
+      ++pages_free;
+    default:
+      ++pages_total;
+    }
+  put_16(pages_free);
+  put_sz(" of ");
+  put_16(pages_total);
+  put_sz(" pages free.\n");
+
   put_sz("Welcome to Portland version 0.0.8!\n");
   while (1)
     put_sz("|\b/\b-\b\\\b");

src/kernel/misc.c

@@ -0,0 +1,46 @@
+/*
+Copyright 2019 Benji Dial
+
+Permission to use, copy, modify, and/or distribute this
+software for any purpose with or without fee is hereby
+granted, provided that the above copyright notice and this
+permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS
+ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
+EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+OF THIS SOFTWARE.
+*/
+
+#include "misc.h"
+#include "vga.h"
+#include <stdbool.h>
+
+void put_16(uint16_t n) {
+  bool s = false;
+  if (n / 10000) {
+    put_char((uint8_t)'0' + n / 10000);
+    s = true;
+  }
+  n %= 10000;
+  if (n / 1000 || s) {
+    put_char((uint8_t)'0' + n / 1000);
+    s = true;
+  }
+  n %= 1000;
+  if (n / 100 || s) {
+    put_char((uint8_t)'0' + n / 100);
+    s = true;
+  }
+  n %= 100;
+  if (n / 10 || s) {
+    put_char((uint8_t)'0' + n / 10);
+    s = true;
+  }
+  put_char((uint8_t)'0' + n % 10);
+}

src/kernel/misc.h

@@ -0,0 +1,27 @@
+/*
+Copyright 2019 Benji Dial
+
+Permission to use, copy, modify, and/or distribute this
+software for any purpose with or without fee is hereby
+granted, provided that the above copyright notice and this
+permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS
+ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
+EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+OF THIS SOFTWARE.
+*/
+
+#include <stdint.h>
+
+#ifndef MISC_H
+#define MISC_H
+
+void print_32(uint32_t n);
+
+#endif