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.th "80.out" 5 "March 1,1977"
.sh NAME
80.out \*- assembler and link editor output
.sh DESCRIPTION
.it "80.out"
is the output file of the assembler
.it "as80"
and the link editor
.it "ld80".
Both programs make
.it "80.out"
executable if there were no
errors and no unresolved external references.
.s3
.it 80.out
has five sections:
header, text, data, relocation information and a symbol table (in that order).
The last two sections may be empty if the program was loaded with
the ``\*-b'', ``\*-d'' or ``\*-t'' option of
.it ld80.
.s1
(Constants beginning with `0' are octal values.)
.s3
.it HEADER
.s3
The header always contains 040 bytes:
.lp +10 8
Address Contents
.lp +10 8
(octal)
.s1
.lp +10 8
0-1 Magic number (0413)
.lp +10 8
2-3 Size of text segment
.lp +10 8
4-5 Size of data segment
.lp +10 8
6-7 Size of bss segment
.lp +10 8
10-11 Size of symbol table
.lp +10 8
12-13 Load origin of text segment
.lp +10 8
14-15 Load origin of data segment
.lp +10 8
16-20 Load origin of bss segment
.lp +10 8
20-21 Size of relocation table
.lp +10 8
22-23 A word of flags
.lp +10 8
24-37 Padding
.s3
.i0
The size of each segment is in bytes.
The size of the header is not included in any of the other sizes.
.s3
The flag values are:
.lp +20 7
Bit Meaning
.lp +20 7
0 If set, no relocation information is present.
.i0
.s3
The start of the text segment in the file is 040,
the start of the data is (040 + text size),
the start of the relocation is (040 + text + data size),
and the start of the symbol table is (040 + text size + data size + relocation size).
.s3
.it "RELOCATION INFORMATION"
.s3
The relocation information (if present)
occupies one or two bytes for each byte or word of text or data.
The bits of the relocation word (or byte) are:
.s3
.lp +10 8
Bit Meaning
.s3
.lp +10 8
6-15 Symbol number in symbol table for external references.
The firat symbol is numbered 0.
.lp +10 8
5 High-byte flag: If set, the next byte of text or data is to be treated as the high
order byte of a 16-bit quantity for relocation purposes.
.lp +10 8
4 Two-byte flag: If set, the next two bytes of text or data are to be
treated as a 16-bit quantity for relocation purposes.
.lp +10 8
3 External flag: If set, bits 15-6 contain a symbol number, otherwise, only one byte
of relocation information is present.
.lp +10 8
0-2 Segment information:
.lp +20 5
0 absolute
.lp +20 5
1 text
.lp +20 5
2 data
.lp +20 5
3 bss
.i0
.s3
.sh "SEE ALSO"
"as80" (I), "ld80" (I), "nm80" (I)
.s3
.it "SYMBOL TABLE"
.s1
The symbol table entries consist of six words:
.s3
.lp +10 8
Word Meaning
.s1
.lp 1-4 The first four words contain the left justified, null-padded ASCII symbol name.
.lp +10 8
The fifth word is a flag indicating the type of the symbol.
The following values are possible:
.lp +20 5
00 undefined
.lp +20 5
01 absolute
.lp +20 5
02 text
.lp +20 5
03 data
.lp +20 5
04 bss
.lp +20 5
05 file name symbol (produced by ld80)
.lp +20 5
010 undefined external
.lp +20 5
011 absolute external
.lp +20 5
012 text segment external
.lp +20 5
013 data segment external
.lp +20 5
014 bss segment external
.lp +10 8
6 The sixth word is the value of the symbol.
.i0
.s3
The sixth word of a symbol table entry contains the value of the symbol.
.s3
.s3
The value of a word in the text or data portions which is not
a reference to an undefined external symbol
is exactly that value which will appear in core
when the file is executed.
If a word in the text or data portion
involves a reference to an undefined external symbol,
as indicated by the relocation bits
for that word,
then the value of the word as stored in the file
is an offset from the associated external symbol.
When the file is processed by the
link editor and the external symbol becomes
defined, the value of the symbol will
be added into the word in the file.
.s3
|
