Changeset 102270 in vbox for trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3kit-linker.h

Timestamp:

Nov 23, 2023 12:40:38 AM (12 months ago)

Author:

vboxsync

Message:

bs3kit: Fixed some issues with loading of a fake 63.5 MB floppy. Added optional checksumming of the images we load (disabled by default, as it's slow in IEM). bugref:10371

File:

• trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3kit-linker.h (modified) (4 diffs)

trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3kit-linker.h

@@ -53 +53 @@
     uint8_t     cFATs;                  /**< 010h */
     uint16_t    cRootDirEntries;        /**< 011h */
-    uint16_t    cTotalSectors;          /**< 013h */
+    uint16_t    cTotalSectors;          /**< 013h - We (ab)use this for the checksum length in sectors. */
     uint8_t     bMediaDescriptor;       /**< 015h */
     uint16_t    cSectorsPerFAT;         /**< 016h */
@@ -63 +63 @@
     uint8_t     bFlagsEtc;              /**< 025h */
     uint8_t     bExtendedSignature;     /**< 026h */
-    uint32_t    dwSerialNumber;         /**< 027h */
+    uint32_t    dwSerialNumber;         /**< 027h - We (ab)use this for the base image checksum. */
     char        abLabel[11];            /**< 02bh */
     char        abFSType[8];            /**< 036h */
@@ -104 +104 @@
     int32_t     offStrings;         /**< Relative address (to entry start) of the string table. */
     uint32_t    offFilename;        /**< String table offset of the DLL name (sans path, with extension). */
+    uint32_t    uChecksum;          /**< Simple checksum of all the on-disk image bits. */
 } BS3HIGHDLLENTRY;
 /** Magic value for BS3HIGHDLLENTRY. */
@@ -125 +126 @@
 
 
+/** Initial value for Bs3CalcChecksum. */
+#define BS3_CALC_CHECKSUM_INITIAL_VALUE 1
+
+/**
+ * Calculates an Adler-32 checksum.
+ */
+DECLINLINE(uint32_t) Bs3CalcChecksum(uint32_t uChecksum, uint8_t const RT_FAR *pbSrc, size_t cbSrc)
+{
+    uint32_t uA = RT_LO_U16(uChecksum);
+    uint32_t uB = RT_HI_U16(uChecksum);
+
+    while (cbSrc-- > 0)
+    {
+        uA = (uA + *pbSrc++) % 0xfff1;
+        uB = (uA + uB)       % 0xfff1;
+    }
+
+    return RT_MAKE_U32(uA, uB);
+}
+
 #endif /* !BS3KIT_INCLUDED_bs3kit_linker_h */