Actually use memcmp() for the DOSEMU comparison; we can't seem to get

it right any other way...

2 files changed, 18 insertions, 2 deletions

diff --git a/memdisk/memdisk.h b/memdisk/memdisk.h
index 68a92d39..f7283886 100644
--- a/memdisk/memdisk.h
+++ b/memdisk/memdisk.h
@@ -47,6 +47,23 @@ memcpy_endptr(void *__d, const void *__s, unsigned int __n)
   return (void *)((char *)__d + __n);
 }
 
+/* memcmp() */
+static inline int
+memcmp(const void *__a, const void *__b, unsigned int __n)
+{
+  const unsigned char *__aa = __a;
+  const unsigned char *__bb = __b;
+  int __d;
+
+  while ( __n ) {
+    __d = *__bb++ - *__aa++;
+    if ( __d )
+      return __d;
+  }
+
+  return 0;
+}
+
 /* Decompression */
 extern int check_zip(void *indata, uint32_t size, uint32_t *zbytes_p,
                      uint32_t *dbytes_p, uint32_t *orig_crc,
diff --git a/memdisk/setup.c b/memdisk/setup.c
index 0832a266..f8de652a 100644
--- a/memdisk/setup.c
+++ b/memdisk/setup.c
@@ -408,8 +408,7 @@ const struct geometry *get_disk_image_geometry(uint32_t where, uint32_t size)
 
   /* Do we have a DOSEMU header? */
   memcpy(&dosemu, (char *)where+hd_geometry.offset, sizeof dosemu);
-  if ( ((unsigned long *)dosemu.magic)[0] == FOUR('D','O','S','E') &&
-       (((unsigned long *)dosemu.magic)[1] & 0xffffff) == FOUR('M','U',0,0) ) {
+  if ( !memcmp("DOSEMU", dosemu.magic, 7) ) {
     /* Always a hard disk unless overruled by command-line options */
     hd_geometry.driveno = 0x80;
     hd_geometry.type = 0;