Specifications

260 AMD Geode™ GeodeROM Functional Specification
Build Utilities
32087C
20.1.3 RLE.EXE – Run Length Encoded Compression Utility
RLE.EXE is used to compress code/data modules intended for inclusion in an GeodeROM firmware component image.
RLE: Version 1.30
Run Length Encoding utility
Example of usage:
The files RLE generates are:
• RLE.CMP [Compressed version of filename]
• RLE.EXP [Decompressed version of RLE.CMP (i.e., same as filename)]
• RLE.HDR [Header information plus the RLE.CMP file]
Normally, the operation of RLE.EXE is embedded in “makefiles and is transparent to the developer. The following section
details each command line argument that RLE.EXE supports:
RLE.EXE – The “/A” Command Line Argument
The “/A:xxxxxxxx” argument instructs RLE.EXE to insert the physical address xxxxxxxxh in the header that it prepends to
the compressed image. This address specifies the location where the companion decompression code, within the boot
loader, inserts the decompressed code or data module.
RLE.EXE – The “/C” Command Line Argument
The “/C:x” argument instructs RLE.EXE to use the caller-specified compression mode. By default, RLE.EXE tries each
compression method and uses the most optimal. The “/C:x” argument allows the caller to override the optimal method and
use method n (where n=[0, 1, 2 …] instead. This command line switch is used primarily to test RLE.EXE.
RLE.EXE – The “/D” Command Line Argument
The “/D:x” argument instructs RLE.EXE to use the caller-specified decompression mode. By default, RLE.EXE decom-
presses a file based on the compression mode indicator that RLE.EXE placed in the compressed file information header
when the file was originally compressed. The “/D:x” argument allows the caller to override the method contained in the com-
pression information header and use method n (where n=[0, 1, 2 …] instead. This command line switch is used primarily to
test RLE.EXE.
RLE.EXE – The “/B” Command Line Argument
The “/B” command line argument instructs RLE.EXE to embed the string “$BMP” (rather than “$IMG”) in the file’s compres-
sion information header. This argument is used when the source file is a bit-map rather than a code or data image. The pri-
mary use of this argument is to simplify the GeodeROM device’s search for the system’s splash screen image during the
power-on sequence. Table 20-1 details the format of the information header that RLE.EXE prepends to each compressed
code or data image.
RLE filename [Run length encodes filename, finds best fit]
RLE filename /A:xxxx [xxxx = phys dest address (DWORD)]
RLE filename /C:x [x = forced compression mode (0,1,2)
RLE filename /D:x [x = forced decompression mode(0,1,2)]
RLE filename /B [Make header a $BMP not $IMG]
Table 20-1. Information Header Format
Offset Description
00h ‘$IMG’ or ‘$BMP’ image type identification string
04h Compression mode (0 = byte count, 1 = word count, 2 = dword count)
05h Physical address at which to decompress the image
09h Length of code/data image file prior to compression
0Dh Length of code/data image file following compression
11h Checksum of compressed file
15h Start of compressed data