Boot Images; Checksum Algorithm - SMART Embedded Computing MVME3100 Installation And Use Manual

Boot Images

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MOTLoad RTOS Version 2.0, PAL Version 0.b EA02
...
MVME3100>
3.10 Boot Images
Valid boot images whether POST, USER, or MCG, are located on 1MB boundaries within
flash. The image may exceed 1MB in size. An image is determined valid through the
presence of two "valid image keys" and other sanity checks. A valid boot image begins with
a structure as defined in the following table:
Name
UserDefined
ImageKey 1
ImageKey 2
ImageChecksum
ImageSize
ImageName
ImageRamAddress
ImageOffset
ImageFlags
ImageVersion
Reserved
3.10.1

Checksum Algorithm

The checksum algorithm is a simple unsigned word add of each word (4 byte) location in
the image. The image must be a multiple of 4 bytes in length (word-aligned). The content
of the checksum location in the header is not part of the checksum calculation. The
calculation assumes the location to be zero.
The algorithm is implemented using the following code:
58
Type
unsigned integer
unsigned integer
unsigned integer
unsigned integer
unsigned integer
unsigned character
unsigned integer
unsigned integer
unsigned integer
unsigned integer
unsigned integer
MVME3100 Single Board Computer Installation and Use (6806800M28H)
Size Notes
8 User defined
1 0x414c5420
1 0x424f4f54
1 Image checksum
1 Must be a multiple of 4
32 User defined
1 RAM address
1 Offset from header start to entry
Image Flags on page 59
1 Refer to
1 User defined
8 Reserved for expansion
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