Relocating Loader (RLC) Format - Revision history

Jhoger at 07:02, 31 January 2009

2009-01-31T07:02:14Z

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	In the examples I have seen, it occurs on its own		In the examples I have seen, it occurs on its own
	line and is preceded by a space.		line and is preceded by a space.

			[[Category:Model T Developer Reference]]

2009-01-14T05:54:40Z

Overview

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	program. Unlike traditional hexadecimal, however, it uses the ASCII characters		program. Unlike traditional hexadecimal, however, it uses the ASCII characters
	<pre>0123456789:;<=>?</pre>		<pre>0123456789:;<=>?</pre>
	It starts with a header, followed by the body, and ~~ending~~ with a		It starts with a header, followed by the body, and ends with a
	checksum. Whitespace is permitted, and most RLC files seem to keep the data		checksum. Whitespace is permitted, and most RLC files seem to keep the data
	less than 128 bytes per line.		less than 128 bytes per line.

2009-01-14T05:53:54Z

What is RLC

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	== What is RLC ==		== What is RLC ==

	The Model 100 ~~use~~ an 8085 CPU. This CPU does not support position independent		The Model 100 uses an 8085 CPU. This CPU does not support position independent
	machine code, at least in any traditional sense.		machine code, at least in any traditional sense.

2008-12-21T05:00:04Z

START

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	=== START ===		=== START ===

	One value must be supplied at load time~~. This is~~ the START address. START is		One value must be supplied at load time which does not appear
			in the RLC file: the START address. START is
	where the user wants to locate the relocatable image. The first field in the body		where the user wants to locate the relocatable image. The first field in the body
	will be poked into RAM starting at START. Note that there must be sufficient space		will be poked into RAM starting at START. Note that there must be sufficient space

2008-12-21T04:59:12Z

Format

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	checksum. Whitespace is permitted, and most RLC files seem to keep the data		checksum. Whitespace is permitted, and most RLC files seem to keep the data
	less than 128 bytes per line.		less than 128 bytes per line.

			=== START ===

			One value must be supplied at load time. This is the START address. START is
			where the user wants to locate the relocatable image. The first field in the body
			will be poked into RAM starting at START. Note that there must be sufficient space
			CLEAR'ed at START to load the program.

	=== Header ===		=== Header ===

2008-12-20T23:31:02Z

What is RLC

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	language files over the serial port.		language files over the serial port.

	Presumably for these reasons, ~~the authors of programs residing in the M100SIG on~~		Presumably for these reasons, someone created the RLC format. RLC is a representation of an 8085 machine
	~~Compuserve~~ created the RLC format. RLC is a representation of an 8085 machine
	language program that is relocatable and 7-bit clean.		language program that is relocatable and 7-bit clean.

			There are many programs in the Compuserve Model 100 SIG archive, for example, that are formatted
			as RLC files.

	== Format ==		== Format ==

2008-12-20T23:28:20Z

Checksum

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	In the examples I have seen, it occurs on its own		In the examples I have seen, it occurs on its own
	line and is ~~preceeded~~ by a space.		line and is preceded by a space.

2008-12-20T23:28:08Z

Trailer

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	significant byte first).		significant byte first).

	=== ~~Trailer~~ ===		=== Checksum ===

			The RLC file ends with the checksum in decimal format.

			The checksum is the arithmetic sum of all offsets and octets in
			the image. It is at least a 32-bit integer.

			In the examples I have seen, it occurs on its own
			line and is preceeded by a space.

2008-12-20T23:15:36Z

Relocation Offset

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	In hexadecimal, this would represent the offset 0x035E, or 862 in decimal.		In hexadecimal, this would represent the offset 0x035E, or 862 in decimal.

	In order to format as 8085 binary, this is added to the user-requested START address		In order to format as 8085 binary, this is added to the user-requested START
	and formatted in little-endian byte order (least significant byte first).		address for the image and formatted in little-endian byte order (least
			significant byte first).

	=== Trailer ===		=== Trailer ===

2008-12-20T23:00:36Z

Body

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	=== Body ===		=== Body ===

			The body of the RLC file is a sequence of fields and whitespace.
			Whitespace is generally needed just to separate lines.

			The two types of fields are octets and relocation offsets.

			==== Octet ====

			An octet is a two-ASCII-character, base-16 representation of a byte. The high nibble appears first.

			No separator between octets is required.

			==== Relocation Offset ====

			A relocation offset is represented by an '@' sign and followed by a
			big-endian, base-16 representation of an address to be relocated.

			<pre>
			@035>
			</pre>

			In hexadecimal, this would represent the offset 0x035E, or 862 in decimal.

			In order to format as 8085 binary, this is added to the user-requested START address
			and formatted in little-endian byte order (least significant byte first).

	=== Trailer ===		=== Trailer ===