20000317 sourceware import

libgloss/mips/syscalls.c

@@ -0,0 +1,45 @@
+#include <_ansi.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "regs.S"
+
+extern char _end[];
+
+/* FIXME: This is not ideal, since we do a get_mem_info() call for
+   every sbrk() call. */
+char *
+sbrk (nbytes)
+     int nbytes;
+{
+  static char *heap_ptr = _end;
+  static char *heap_start = _end;
+  char        *base;
+  struct s_mem {
+    unsigned int size;
+    unsigned int icsize;
+    unsigned int dcsize;
+  } mem;
+  unsigned int avail = 0;
+
+  /* The sizeof (s_mem.size) must be 4 bytes.  The compiler should be
+     able to eliminate this check */
+  if (sizeof (unsigned int) != 4)
+    return (char *)-1;
+
+  get_mem_info(&mem);
+  /* NOTE: The value returned from the get_mem_info call is the amount
+     of memory, and not the address of the (last byte + 1) */
+
+  if (((size_t)heap_ptr >= heap_start) && ((size_t)heap_ptr < (heap_start + mem.size))) {
+    avail = (heap_start + mem.size) - (size_t)heap_ptr;
+    base = heap_ptr;
+  } /* else will fail since "nbytes" will be greater than zeroed "avail" value */
+
+  if ((nbytes > avail) || (heap_ptr + nbytes < _end))
+   base = (char *)-1;
+  else
+   heap_ptr += nbytes;
+
+  return base;
+}