User`s guide

11–2 MAKEROM
ROM Header Information Fields
Figure 11–1 MAKEROM Fields
• Validation Pattern
The first quadword contains a special signature pattern that is used to verify that
this “special” ROM header has been located. The validation pattern is
0x5A5AC3C3A5A53C3C.
• Header Size (Bytes)
The header size is the next longword. This is provided to allow for some
backward compatibility in the event that the header is extended in the future.
When the header is located, current versions of SROM code determine where the
image begins based on the header size. Additional data added to the header in the
future will simply be ignored by current SROM code. Additionally, the header
size = 0x20 implies Version 0 of this header specification. For any other size, see
Header Rev to determine header version.
• Image Checksum
The next longword contains the image checksum. This is used to verify the
integrity of the ROM. Checksum is computed in the same fashion as the header
checksum. Although this field was provided with Version 0 of this header
specification, the checksum was not really computed until Version 1.
Validation Pattern 0x5A5AC3C3
Inverse Validation Pattern 0xA5A53C3C
Header Size (Bytes)
Image Checksum
Image Size (Memory Footprint)
Decompression Flag
Destination Address Lower Longword
Destination Address Upper Longword
ROM Image Size
Optional Firmware ID <31:0>
Optional Firmware ID <63:32>
0x00
0x04
0x08
0x0C
0x10
0x14
0x18
0x1C
0x24
0x28
0x2C
0x30
0x34
0x20
all
all
all
all
all
all
all
all
1+
1+
1+
1+
2+
1+
Firmware ID <15:8>
Reserved <31:24>
Header Rev <7:0>
Header Rev Ext <23:16>
ROM Offset <31:2>
ROM Offset Valid <0>
Header Checksum (excluding this field)
31
Offset
Header
Revisions
Supported
FM-05103.AI4
0