Interdata_v6/usr/doc/man/man5/a.out.5

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.th A.OUT V 8/12/77
.sh NAME
a.out - link editor format
.sh DESCRIPTION
The a.out file produced by
.it as
and accepted by
.it ld
has the format of a PDP-11 UNIX a.out file,
with the following differences:

.lp +16 16
Magic number	The magic number is a 32-bit fullword.

.lp +16 16
Header	The header is 8 words (32 bytes) long.

.lp +16 16
Symbol table	 Each entry is 4 words
(16 bytes) long, containing an 8-character name,
one-word type and one-word value.

.lp +16 16
Relocation bits	\c
There is one 16-bit halfword of relocation bits per
halfword of text and data.
Bit 0 of the relocation halfword indicates,
if
.it on,
that the corresponding text or data halfword is the high-order 16 bits
of a fullword relocatable address;
and the next relocation halfword is
.it zero
for a 24-bit address or
.it nonzero
for a 32-bit address.
.i0
.sh "SEE ALSO"
The Book