Provided by: srecord_1.58-1_amd64 
NAME
srec_intel - Intel Hexadecimal object file format specification
DESCRIPTION
This format is also known as the Intel MCS‐86 Object format.
This document describes the hexadecimal object file format for the Intel 8‐bit, 16‐bit,
and 32‐bit microprocessors. The hexadecimal format is suitable as input to PROM
programmers or hardware emulators.
Hexadecimal object file format is a way of representing an absolute binary object file in
ASCII. Because the file is in ASCII instead of binary, it is possible to store the file
is non‐binary medium such as paper‐tape, punch cards, etc.; and the file can also be
displayed on CRT terminals, line printers, etc.. The 8‐bit hexadecimal object file format
allows for the placement of code and data within the 16‐bit linear address space of the
Intel 8‐bit processors. The 16‐bit hexadecimal format allows for the 20‐bit segmented
address space of the Intel 16‐bit processors. And the 32‐bit format allows for the 32‐bit
linear address space of the Intel 32‐bit processors.
--address-length=2 “i8hex” 16‐bit
--address-length=3 “i16hex” 20‐bit segmented
--address-length=4 “i32hex” 32‐bit linear
The hexadecimal representation of binary is coded in ASCII alphanumeric characters. For
example, the 8‐bit binary value 0011‐1111 is 3F in hexadecimal. To code this in ASCII,
one 8‐bit byte containing the ASCII code for the character '3' (0011‐0011 or 0x33) and one
8‐bit byte containing the) ASCII code for the character 'F' (0100‐0110 or 0x46) are
required. For each byte value, the high‐order hexadecimal digit is always the first digit
of the pair of hexadecimal digits. This representation (ASCII hexadecimal) requires twice
as many bytes as the binary representation.
A hexadecimal object file is blocked into records, each of which contains the record type,
length, memory load address and checksum in addition to the data. There are currently six
(6) different types of records that are defined, not all combinations of these records are
meaningful, however. The record are:
• Data Record (8‐, 16‐, or 32‐bit formats)
• End of File Record (8‐, 16‐, or 32‐bit formats)
• Extended Segment Address Record (16‐ or 32‐bit formats)
• Start Segment Address Record (16‐ or 32‐bit formats)
• Extended Linear Address Record (32‐bit format only)
• Start Linear Address Record (32‐bit format only)
General Record Format
┌───────┬────────┬────────┬────────┬────────┬────────┐
│Record │ Record │ Load │ Record │ Data │ Check │
│Mark │ Length │ Offset │ Type │ │ sum │
└───────┴────────┴────────┴────────┴────────┴────────┘
Record Mark.
Each record begins with a Record Mark field containing 0x3A, the ASCII code for
the colon (“:”) character.
Record Length
Each record has a Record Length field which specifies the number of bytes of
information or data which follows the Record Type field of the record. This field
is one byte, represented as two hexadecimal characters. The maximum value of the
Record Length field is hexadecimal 'FF' or 255.
Load Offset
Each record has a Load Offset field which specifies the 16‐bit starting load
offset of the data bytes, therefore this field is only used for Data Records. In
other records where this field is not used, it should be coded as four ASCII zero
characters (“0000” or 0x30303030). This field is two byte, represented as four
hexadecimal characters.
Record Type
Each record has a Record Type field which specifies the record type of this
record. The Record Type field is used to interpret the remaining information
within the record. This field is one byte, represented as two hexadecimal
characters. The encoding for all the current record types are:
0 Data Record
1 End of File Record
2 Extended Segment Address Record
3 Start Segment Address Record
4 Extended Linear Address Record
5 Start Linear Address Record
Data Each record has a variable length Data field, it consists of zero or more bytes
encoded as pairs of hexadecimal digits. The interpretation of this field depends
on the Record Type field.
Checksum
Each record ends with a Checksum field that contains the ASCII hexadecimal
representation of the two's complement of the 8‐bit bytes that result from
converting each pair of ASCII hexadecimal digits to one byte of binary, from and
including the Record Length field to and including the last byte of the Data
field. Therefore, the sum of all the ASCII pairs in a record after converting to
binary, from the Record Length field to and including the Checksum field, is zero.
Extended Linear Address Record
(32‐bit format only)
┌────────┬─────────┬─────────┬─────────┬─────────┬─────────┐
│Record │ Record │ Load │ Record │ ULBA (2 │ Check │
│Mark │ Length │ Offset │ Type │ bytes) │ sum │
│(“:”) │ (2) │ (0) │ (4) │ │ │
└────────┴─────────┴─────────┴─────────┴─────────┴─────────┘
The 32‐bit Extended Linear Address Record is used to specify bits 16‐31 of the Linear Base
Address (LBA), where bits 0‐15 of the LBA are zero. Bits 16‐31 of the LBA are referred to
as the Upper Linear Base Address (ULBA). The absolute memory address of a content byte in
a subsequent Data Record is) obtained by adding the LBA to an offset calculated by adding
the Load Offset field of the containing Data Record to the index of the byte in the Data
Record (0, 1, 2, ... n). This offset addition is done) modulo 4G (i.e. 32‐bits from
0xFFFFFFFF to 0x00000000) results in wrapping around from the end to the beginning of the
4G linear address defined by the LBA. The linear address at which a particular byte is
loaded is calculated as:
(LBA + DRLO + DRI) MOD 4G
where:
DRLO is the Load Offset field of a Data Record.
DRI is the data byte index within the Data Record.
When an Extended Linear Address Record defines the value of LBA, it may appear anywhere
within a 32‐bit hexadecimal object file. This value remains in effect until another
Extended Linear Address Record is encountered. The LBA defaults to zero until an Extended
Linear Address Record is encountered. The contents of the individual fields within the
record are:
Record Mark
This field contains 0x3A, the hexadecimal encoding of the ASCII colon (“:”)
character.
Record Length
The field contains 0x3032, the hexadecimal encoding of the ASCII characters “02”,
which is the length, in bytes, of the ULBA data information within this record.
Load Offset
This field contains 0x30303030, the hexadecimal encoding of the ASCII characters
“0000”, since this field is not used for this record.
Record Type
This field contains 0x3034, the hexadecimal encoding of the ASCII character “04”,
which specifies the record type to be an Extended Linear Address Record.
ULBA This field contains four ASCII hexadecimal digits that specify the 16‐bit Upper
Linear Base Address value. The value is encoded big‐endian (most significant
digit first).
Checksum
This field contains the check sum on the Record Length, Load Offset, Record Type,
and ULBA fields.
Extended Segment Address Record
(16‐ or 32‐bit formats)
┌────────┬─────────┬─────────┬─────────┬─────────┬─────────┐
│Record │ Record │ Load │ Record │ USBA (2 │ Check │
│Mark │ Length │ Offset │ Type │ bytes) │ sum │
│(“:”) │ (2) │ (0) │ (2) │ │ │
└────────┴─────────┴─────────┴─────────┴─────────┴─────────┘
The 16‐bit Extended Segment Address Record is used to specify bits 4‐19 of the Segment
Base Address (SBA), where bits 0‐3 of the SBA are zero. Bits 4‐19 of the SBA are referred
to as the Upper Segment Base Address (USBA). The absolute memory address of a content
byte in a subsequent Data Record is) obtained by adding the SBA to an offset calculated by
adding the Load Offset field of the containing Data Record to the index of the byte in the
Data Record (0, 1, 2, ... n). This offset addition is done modulo 64K (i.e. 16‐bits from
0xFFFF to 0x0000 results in wrapping around from the end to the beginning of the 64K
segment defined by the SBA. The address at which a particular byte is loaded is
calculated as:
SBA + ((DRLO + DRI) MOD 64K)
where:
DRLO is the LOAD OFFSET field of a Data Record.
DRI is the data byte index within the Data Record.
When an Extended Segment Address Record defines the value of SBA, it may appear anywhere
within a 16‐bit hexadecimal object file. This value remains in effect until another
Extended Segment Address Record is encountered. The SBA defaults to zero until an
Extended Segment Address Record is encountered.
The contents of the individual fields within the record are:
Record Mark
This field contains 0x3A, the hexadecimal encoding of the ASCII colon (“:”)
character.
Record Length
The field contains 0x3032, the hexadecimal encoding of the ASCII characters '02',
which is the length, in bytes, of the USBA data information within this record.
Load Offset
This field contains 0x30303030, the hexadecimal encoding of the ASCII characters
'0000', since this field is not used for this record.
Record Type
This field contains 0x3032, the hexadecimal encoding of the ASCII character “02”,
which specifies the record type to be an Extended Segment Address Record.
USBA This field contains four ASCII hexadecimal digits that specify the 16‐bit Upper
Segment Base Address value. The field is encoded big‐endian (most significant
digit first).
Checksum
This field contains the check sum on the Record length, Load Offset, Record Type,
and USBA fields.
Data Record
(8‐, 16‐ or 32‐bit formats)
┌───────┬────────┬────────┬────────┬────────┬────────┐
│Record │ Record │ Load │ Record │ Data │ Check │
│Mark │ Length │ Offset │ Type │ │ sum │
│(“:”) │ │ │ │ │ │
└───────┴────────┴────────┴────────┴────────┴────────┘
The Data Record provides a set of hexadecimal digits that represent the ASCII code for
data bytes that make up a portion of a memory image. The method for calculating the
absolute address (linear in the 8‐bit and 32‐bit case and segmented in the 16‐bit case)
for each byte of data is described in the discussions of the Extended Linear Address
Record and the Extended Segment Address Record.
The contents of the individual fields within the record are:
Record Mark
This field contains 0x3A, the hexadecimal encoding of the ASCII colon (“:”)
character.
Record Length
The field contains two ASCII hexadecimal digits that specify the number of data
bytes in the record. The maximum value is 255 decimal.
Load Offset
This field contains four ASCII hexadecimal digits representing the offset from the
LBA (see Extended Linear Address Record see Extended Segment Address Record)
defining the address which the first byte of the data is to be placed.
Record Type
This field contains 0x3030, the hexadecimal encoding of the ASCII character “00”,
which specifies the record type to be a Data Record.
Data This field contains pairs of ASCII hexadecimal digits, one pair for each data
byte.
Checksum
This field contains the check sum on the Record Length, Load Offset, Record Type,
and Data fields.
Note: Care must be taken when the addresses with an record span the end of addressing.
The behaviour is different for linear and segmented addressing modes.
linear If a record starts just short of 2**32, and would finish after 2**32, the later
part of the record wraps around to address 0. TP 8n segment If a record starts
just for of a 2**16 boundary, and would finish after that 2**16 boundary, the
later part of the record wraps around to address 0 within the same segment (not
the next segment).
The srec_cat(1) program will never output records such as these, it will always produce
separate records on output.
Start Linear Address Record
(32‐bit format only)
┌───────┬────────┬────────┬────────┬────────┬────────┐
│Record │ Record │ Load. │ Record │ EIP (4 │ Check │
│Mark │ Length │ Offset │ Type │ bytes) │ sum │
│(“:”) │ (4) │ (0) │ (5) │ │ │
└───────┴────────┴────────┴────────┴────────┴────────┘
The Start Linear Address Record is used to specify the execution start address for the
object file. The value given is the 32‐bit linear address for the EIP register. Note
that this record only specifies the code address within the 32‐bit linear address space of
the 80386. If the code is to start execution in the real mode of the 80386, then the
Start Segment Address Record should be used instead, since that record specifies both the
CS and IP register contents necessary for real mode.
The Start Linear Address Record can appear anywhere in a 32‐bit hexadecimal object file.
If such a record is not present in a hexadecimal object file, a loader is free to assign a
default execution start address.
The contents of the individual fields within the record are:
Record mark
This field contains 0x3A, the hexadecimal encoding of the ASCII colon (“:”)
character.
Record length
The field contains 0x3034, the hexadecimal encoding of the ASCII characters “04”,
which is the length, in bytes, of the EIP register content within this record.
Load Offset
This field contains 0x30303030, the hexadecimal encoding of the ASCII characters
“0000”, since this field is not used for this record.
Record Type
This field contains 0x3035, the hexadecimal encoding of the ASCII character “05”,
which specifies the record type to be a Start Linear Address Record.
EIP This field contains eight ASCII hexadecimal digits that specify the 32‐bit EIP
register contents. The field is encoded big‐endian (most significant digit
first).
Checksum
This field contains the check sum on the Record length, Load Offset, Record Type,
and EIP fields.
Start Segment Address Record
(16‐ or 32‐bit formats)
┌───────┬────────┬────────┬────────┬────────┬────────┬────────┐
│Record │ Record │ Load. │ Record │ CS (2 │ IP (2 │ Check │
│Mark │ Length │ Offset │ Type │ bytes) │ bytes) │ sum │
│(“:”) │ (4) │ (0) │ (3) │ │ │ │
└───────┴────────┴────────┴────────┴────────┴────────┴────────┘
The Start Segment Address Record is used to specify the execution start address for the
object file. The value given is the 20‐bit segment address for the CS and IP registers.
Note that this record only specifies the code address within the 20‐bit segmented address
space of the 8086/80186. The Start Segment Address Record can appear anywhere in a 16‐bit
hexadecimal object file. If such a record is not present in a hexadecimal object file, a
loader is free to assign a default start address.
The contents of the individual fields within the record are:
Record Mark
This field contains 0x3A, the hexadecimal encoding of the ASCII colon (“:”)
character.
Record Length
The field contains 0x3034, the hexadecimal encoding of the ASCII characters “04”,
which is the length, in bytes, of the CS and IP register contents within this
record.
Load Offset
This field contains 0x30303030, the hexadecimal encoding of the ASCII characters
“0000”, since this field is not used for this record.
Record Type
This field contains 0x3033, the hexadecimal encoding of the ASCII character '03',
which specifies the record type to be a Start Segment Address Record.
CS This field contains four ASCII hexadecimal digits that specify the 16‐bit CS
register contents. The field is encoded big‐endian (most significant digit
first).
IP This field contains four ASCII hexadecimal digits that specify the 16‐bit IP
register contents. The field is encoded big‐endian (most significant digit
first).
Checksum
This field contains the check sum on the Record length, Load Offset, Record Type,
CS, and IP fields.
End of File Record
(8‐, 16‐, or 32‐bit formats)
┌───────┬────────┬────────┬────────┬────────┐
│Record │ Record │ Load │ Record │ Check │
│Mark │ Length │ Offset │ Type │ sum │
│(“:”) │ (0) │ (0) │ (1) │ (0xFF) │
└───────┴────────┴────────┴────────┴────────┘
The End of File Record specifies the end of the hexadecimal object file.
The contents of the individual fields within the record are:
Record mark
This field contains 0x3A, the hexadecimal encoding of the ASCII colon (“:”)
character.
Record Length
The field contains 0x3030, the hexadecimal encoding of the ASCII characters “00”.
Since this record does not contain any Data bytes, the length is zero.
Load Offset
This field contains 0x30303030, the hexadecimal encoding of the ASCII characters
“0000”, since this field is not used for this record. In ancient times, i8hex
used this for the start address record.
Record Type
This field contains 0x3031, the hexadecimal encoding of the ASCII character “01”,
which specifies the record type to be an End of File Record.
Checksum
This field contains the check sum an the Record Length, Load Offset, and Record
Type fields. Since all the fields are static, the check sum can also be
calculated statically, and the value is 0x4646, the hexadecimal encoding of the
ASCII characters “FF”.
Size Multiplier
In general, binary data will expand in sized by approximately 2.3 times when represented
with this format.
EXAMPLE
Here is an example Intel hex file. It contains the data “Hello, World” to be loaded at
address 0.
:0D00000048656C6C6F2C20576F726C640AA1
:00000001FF
REFERENCE
This information comes (very indirectly) from Microprocessors and Programmed Logic, Second
Edition, Kenneth L. Short, 1987, Prentice‐Hall, ISBN 0‐13‐580606‐2.
http://en.wikipedia.org/wiki/Intel_HEX
COPYRIGHT
srec_cat version 1.58
Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
2010, 2011 Peter Miller
The srec_cat program comes with ABSOLUTELY NO WARRANTY; for details use the 'srec_cat
-VERSion License' command. This is free software and you are welcome to redistribute it
under certain conditions; for details use the 'srec_cat -VERSion License' command.
AUTHOR
Peter Miller E‐Mail: pmiller@opensource.org.au
/\/\* WWW: http://miller.emu.id.au/pmiller/
Derivation
This manual page is derived from a file marked as follows:
Intel Hexadecimal Object File Format Specification; Revision A, 1/6/88
Disclaimer: Intel makes no representation or warranties with respect to the contents
hereof and specifically disclaims any implied warranties of merchantability or fitness for
any particular purpose. Further, Intel reserves the right to revise this publication from
time to time in the content hereof without obligation of Intel to notify any person of
such revision or changes. The publication of this specification should not be construed
as a commitment on Intel's part to implement any product.