hw2 done

lib/utils.c

@@ -0,0 +1,132 @@
+#include <utils.h>
+#include <errcode.h>
+#include <uart.h>
+
+uint32_t msb32(uint32_t x)
+{
+  static const int msb[32] = {
+    0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30,
+    8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31
+  };
+
+  x |= x >> 1;
+  x |= x >> 2;
+  x |= x >> 4;
+  x |= x >> 8;
+  x |= x >> 16;
+  
+  return msb[(uint32_t)(x * 0x07c4acddu) >> 27];
+}
+
+uint32_t hton32(const uint32_t h)
+{
+  const uint8_t *p = (const void *)&h;
+
+  return (uint32_t)p[0] << 24 |
+         (uint32_t)p[1] << 16 |
+         (uint32_t)p[2] << 8 |
+         (uint32_t)p[3];
+}
+
+uint32_t ntoh32(const uint32_t h)
+{
+  return hton32(h);
+}
+
+uint64_t hton64(const uint64_t h)
+{
+  return (uint64_t)hton32(h & 0xffffffff) << 32 |
+         (uint64_t)hton32(h >> 32);
+}
+
+uint64_t ntoh64(const uint64_t h)
+{
+  return hton64(h);
+}
+
+int isspace(int c)
+{
+  switch (c) {
+  case ' ':
+  case '\t':
+  case '\n':
+  case '\v':
+  case '\f':
+  case '\r':
+    return true;
+  }
+  return false;
+}
+
+int isdigit(int c)
+{
+  return ('0' <= c && c <= '9');
+}
+
+int isxdigit(int c)
+{
+  return ('0' <= c && c <= '9') || 
+         ('a' <= c && c <= 'f') ||
+         ('A' <= c && c <= 'F');
+}
+
+int isupper(int c)
+{
+  return ('A' <= c && c <= 'F');
+}
+
+int32_t atoi32(const char *s)
+{
+  if (!s)
+    exit(ERR_CONVERSION);
+
+  int is_neg = 0;
+  if (*s != '\0' && *s == '-')
+    is_neg = 1, s++;
+
+  int32_t ret = 0;
+  for (; *s != '\0'; ++s) {
+    if (!isdigit(*s))
+      exit(ERR_CONVERSION);
+    ret *= 10, ret += *s - '0';
+  }
+
+  return is_neg ? -ret : ret;
+}
+
+uint32_t atoh32(const char *s)
+{
+  if (!s)
+    exit(ERR_CONVERSION);
+
+  uint32_t ret = 0;
+  for (int i = 8; i--; ++s) {
+    if (!isxdigit(*s))
+      exit(ERR_CONVERSION);
+    ret <<= 4, ret |= (isdigit(*s) ? *s - '0' : 
+                      (isupper(*s) ? *s - 'A' + 10 : 
+                                     *s - 'a' + 10));
+  }
+
+  return ret;
+}
+
+void exit(int exit_code)
+{
+  static int print = 0;
+  if (!print) {
+    uart_puts(
+      "OOPS! YOUR KERNEL DEAD" ENDL
+      "ERROR CODE: "
+    );
+    uart_hex(exit_code);
+    uart_puts(ENDL);
+    print = 1;
+  }
+
+  asm volatile(
+    "wfe\n"
+    "b exit"
+  );
+  __builtin_unreachable();
+}