DESCRIPTION
An S-record file consists of a sequence of specially formatted ASCII character strings. An S-record will be less than or equal to 78 bytes in length.The original Unix man page on S-records is the only place that a 78-byte limit on total record length or 64-byte limit on data length is documented. These values should not be trusted for the general case. Always assume that a record can be as long as 514 (decimal) characters in length (255 * 2 = 510, plus 4 characters for the type and count fields), plus any terminating character(s). Input buffers should be long enough to hold 515 chars, thus leaving room for the terminating null character. The order of S-records within a file is of no significance and no particular order may be assumed with the exception of the termination record at the end.
The general format of an S-record follows:
+-------------------//------------------//-----------------------+ | type | count | address | data | checksum | +-------------------//------------------//-----------------------+type -- A char[2] field. These characters describe the type of record (S0, S1, S2, S3, S5, S7, S8, or S9).count -- A char[2] field. These characters when paired and interpreted as a hexadecimal value, display the count of remaining character pairs in the record.
address -- A char[4,6, or 8] field. These characters grouped and interpreted as a hexadecimal value, display the address at which the data field is to be loaded into memory. The length of the field depends on the number of bytes necessary to hold the address. A 2-byte address uses 4 characters, a 3-byte address uses 6 characters, and a 4-byte address uses 8 characters.
data -- A char [0-64] field. These characters when paired and interpreted as hexadecimal values represent the memory loadable data or descriptive information.
checksum -- A char[2] field. These characters when paired and interpreted as a hexadecimal value display the least significant byte of the ones complement of the sum of the byte values represented by the pairs of characters making up the count, the address, and the data fields.
Each record is terminated with a line feed. If any additional or different record terminator(s) or delay characters are needed during transmission to the target system it is the responsibility of the transmitting program to provide them.
S0 Record. The address field is unused and will be filled with zeros (0x0000). The code/data field contains descriptive information identifying the following block of S-records as having been created by EASy68K.
S1 Record. The address field is interpreted as a 2-byte address. The data field is composed of memory loadable data.
S2 Record. The address field is interpreted as a 3-byte address. The data field is composed of memory loadable data.
S3 Record. The address field is interpreted as a 4-byte address. The data field is composed of memory loadable data.
S5 Record. The address field is interpreted as a 2-byte value and contains the count of S1, S2, and S3 records previously transmitted. There is no data field. (EASy68K does not generate this record.)
S7 Record. Termination record. The address field contains the starting execution address and is interpreted as 4-byte address. There is no data field. This is the last record in the file. (EASyBIN always uses this termination record when creating S-Record files.)
S8 Record. Termination record. The address field contains the starting execution address and is interpreted as 3-byte address. There is no data field. This is the last record in the file. (EASy68K always uses this termination record when creating S-Record files.)
S9 Record. Termination record. The address field contains the starting execution address and is interpreted as 2-byte address. There is no data field. This is the last record in the file.
EXAMPLE
The following program was assembled with EASy68K. The .L68 file is shown. The .L68 file contains the address, machine code, line number and source code.
00001000 Starting Address
Assembler used: EASy68K Editor v1.9.2
Created On: 1/28/2004 4:51:58 PM
Address Machine Code Line Source Code
00000000 1 *-----------------------------------------------------------
00000000 2 * Program Number: S-Record demo for EASy68k
00000000 3 * Written by : Chuck Kelly
00000000 4 * Date Created : Jan-28-2004
00000000 5 * Description : demonstrate the S-Record file format used by EASy68K.
00000000 6 *
00000000 7 * This program is public domain.
00000000 8 *-----------------------------------------------------------
00000000 9
00001000 10 START ORG $1000 the program will load into address $1000
00001000 123C 0003 11 move.b #3,d1 put 3 in low byte of data register D1
00001004 5A01 12 add.b #5,d1 add 5 to low byte of data register D1
00001006 13 * Display string textD1
00001006 303C 000E 14 move #14,d0 load task number into D0
0000100A 43F9 00044446 15 lea textD1,a1 load address of string to display into A1
00001010 4E4F 16 trap #15 trap #15 activates input/output task
00001012 17 * Display D1 as a number
00001012 303C 0003 18 move #3,d0 task number 3 into D0
00001016 19 * task number 3 is used to display the contents of D1.L as a number
00001016 4E4F 20 trap #15 display number in D1.l
00001018 4EB9 00022222 21 jsr newLine
0000101E 22 * Stop execution
0000101E 4E72 2000 23 STOP #$2000
00001022 24
00022222 25 org $22222 this subroutine is located at address $22222
00022222 26 * Subroutine to display Carriage Return and Line Feed
00022222 27 newLine:
00022222 48E7 8040 28 movem.l d0/a1,-(a7) push d0 & a1
00022226 303C 000E 29 move #14,d0 task number into D0
0002222A 43F9 00044462 30 lea crlf,a1 address of string
00022230 4E4F 31 trap #15 display return, linefeed
00022232 4CDF 0201 32 movem.l (a7)+,d0/a1 restore d0 & a1
00022236 4E75 33 rts return
00022238 34
00044444 35 org $44444 this data is located at address $44444
00044444 36 sum2 ds.w 1 reserve word of memory for sum2
00044446 44 31 20 63 6F 6E ... 37 textD1 dc.b 'D1 contains: ',0 null terminated string
00044454 44 32 20 63 6F 6E ... 38 textD2 dc.b 'D2 contains: ',0 null terminated string
00044462 0D 0A 00 39 crlf dc.b $d,$a,0 carriage return & line feed, null
00044465 40
00044465 41 */\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
00044465 42 * E R R O R E R R O R E R R O R E R R O R E R R O R
00044465 43 */\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
00044465 44 * EASy68K does not support addresses beyond $FFFFFF or 16MBytes
00044465 45 * Comment out the following org directive if you want to run this program.
12345678 46 org $12345678
12345678 69 6E 76 61 6C 69 ... 47 junk dc.b 'invalid address'
12345687 48
12345687 49 END START end of program with start address specified
The S-record file created from the above program follows:.
S021000036384B50524F47202020313143524541544544204259204541535936384B6D
S1251000123C00035A01303C000E43F9000444464E4F303C00034E4F4EB9000222224E72200004
S21A02222248E78040303C000E43F9000444624E4F4CDF02014E75C2
S223044446443120636F6E7461696E733A2000443220636F6E7461696E733A20000D0A009A
S31412345678696E76616C69642061646472657373EA
S804001000EB
The S0 Record contains the following information:
/-version number
module name / /-revision number checksum
S0 0000 6 8 K P R O G 1 1 C R E A T E D B Y E A S Y 6 8 K /
S021000036384B50524F47202020313143524541544544204259204541535936384B6DThe version and revision number refer to the EASy68K S-Record file type, not the product version.
The file consists of one S0 record, one S1 record, two S2 records, one S3 record and an S8 record.
The first S1 record is comprised as follows:
S1 25 1000 123C00035A01303C000E43F9000444464E4F303C00034E4F4EB9000222224E722000 04
- S1 S-record type, indicating it is a data record to be loaded at a 2-byte address.
- 25 Hexadecimal (decimal 37), indicating that thirty-seven character pairs, representing a 2 byte address, 34 bytes of binary data, and a 1 byte checksum, follow.
- 1000 Four character 2-byte address field; hexadecimal address $1000, where the data which follows is to be loaded.
- 123C00035A01... 34 character pairs representing the actual binary data.
- 04 The checksum.
The first S2 record is comprised as follows:
S2 1A 022222 48E78040303C000E43F9000444624E4F4CDF02014E75 C2
- S2 S-record type, indicating it is a data record to be loaded at a 3-byte address.
- 1A Hexadecimal (decimal 26), indicating that twenty-six character pairs, representing a 3 byte address, 22 bytes of binary data, and a 1 byte checksum, follow.
- 022222 Six character 3-byte address field; hexadecimal address $022222, where the data which follows is to be loaded.
- 48E78040303C... 22 character pairs representing the actual binary data.
- C2 The checksum.
The second S2 record contains additional data which is to be loaded at address $044446
The first S3 record is comprised as follows:
S3 14 12345678 696E76616C69642061646472657373 EA
- S3 S-record type, indicating it is a data record to be loaded at a 4-byte address.
- 14 Hexadecimal (decimal 20), indicating that twenty character pairs, representing a 4 byte address, 15 bytes of binary data, and a 1 byte checksum, follow.
- 12345678 Eight character 4-byte address field; hexadecimal address $12345678, where the data which follows is to be loaded.
- 696E76616C69... 15 character pairs representing the actual binary data.
- EA The checksum.
The S8 record is comprised as follows:
S8 04 001000 EB
- S8 S-record type, indicating it is a termination record with a 3-byte address.
- 04 Hexadecimal (decimal 4), indicating that four character pairs follow.
- 001000 The address field, hexadecimal address $001000 indicating the starting execution address.
- EB The checksum.
EASy68K always uses the S8 record.