msdos: add lba_to_chs

a1ive · Dec 13, 2019 · a645fed · a645fed · a1ive · Jan 29, 2020
1 parent 4b9b541
commit a645fed
Show file tree

Hide file tree

Showing 3 changed files with 27 additions and 54 deletions.
diff --git a/grub-core/commands/gptsync.c b/grub-core/commands/gptsync.c
@@ -31,33 +31,6 @@
 
 GRUB_MOD_LICENSE ("GPLv3+");
 
-/* Convert a LBA address to a CHS address in the INT 13 format.  */
-/* Taken from grub1. */
-/* XXX: use hardcoded geometry of C = 1024, H = 255, S = 63.
-   Is it a problem?
-*/
-static void
-lba_to_chs (grub_uint32_t lba, grub_uint8_t *cl, grub_uint8_t *ch,
-	    grub_uint8_t *dh)
-{
-  grub_uint32_t cylinder, head, sector;
-  grub_uint32_t sectors = 63, heads = 255, cylinders = 1024;
-
-  sector = lba % sectors + 1;
-  head = (lba / sectors) % heads;
-  cylinder = lba / (sectors * heads);
-
-  if (cylinder >= cylinders)
-    {
-      *cl = *ch = *dh = 0xff;
-      return;
-    }
-
-  *cl = sector | ((cylinder & 0x300) >> 2);
-  *ch = cylinder & 0xFF;
-  *dh = head;
-}
-
 static grub_err_t
 grub_cmd_gptsync (grub_command_t cmd __attribute__ ((unused)),
 		  int argc, char **args)

diff --git a/grub-core/commands/partnew.c b/grub-core/commands/partnew.c
@@ -60,33 +60,6 @@ enum options_partnew
   PARTNEW_LENGTH,
 };
 
-/* Convert a LBA address to a CHS address in the INT 13 format.  */
-/* Taken from grub1. */
-/* XXX: use hardcoded geometry of C = 1024, H = 255, S = 63.
-   Is it a problem?
-*/
-static void
-lba_to_chs (grub_uint32_t lba, grub_uint8_t *cl, grub_uint8_t *ch,
-            grub_uint8_t *dh)
-{
-  grub_uint32_t cylinder, head, sector;
-  grub_uint32_t sectors = 63, heads = 255, cylinders = 1024;
-
-  sector = lba % sectors + 1;
-  head = (lba / sectors) % heads;
-  cylinder = lba / (sectors * heads);
-
-  if (cylinder >= cylinders)
-  {
-    *cl = *ch = *dh = 0xff;
-    return;
-  }
-
-  *cl = sector | ((cylinder & 0x300) >> 2);
-  *ch = cylinder & 0xFF;
-  *dh = head;
-}
-
 struct block_ctx
 {
   grub_disk_addr_t start;

diff --git a/include/grub/msdos_partition.h b/include/grub/msdos_partition.h
@@ -140,4 +140,31 @@ grub_partition_msdos_iterate (grub_disk_t disk,
 			      grub_partition_iterate_hook_t hook,
 			      void *hook_data);
 
+/* Convert a LBA address to a CHS address in the INT 13 format.  */
+/* Taken from grub1. */
+/* XXX: use hardcoded geometry of C = 1024, H = 255, S = 63.
+   Is it a problem?
+*/
+static inline void
+lba_to_chs (grub_uint32_t lba, grub_uint8_t *cl, grub_uint8_t *ch,
+            grub_uint8_t *dh)
+{
+  grub_uint32_t cylinder, head, sector;
+  grub_uint32_t sectors = 63, heads = 255, cylinders = 1024;
+
+  sector = lba % sectors + 1;
+  head = (lba / sectors) % heads;
+  cylinder = lba / (sectors * heads);
+
+  if (cylinder >= cylinders)
+  {
+    *cl = *ch = *dh = 0xff;
+    return;
+  }
+
+  *cl = sector | ((cylinder & 0x300) >> 2);
+  *ch = cylinder & 0xFF;
+  *dh = head;
+}
+
 #endif /* ! GRUB_PC_PARTITION_HEADER */