.TH MINTERM 10.6
.SH NAME
minterm \- minterm file format
.SH DESCRIPTION
The
.I minterm
file format consists of at least one binary valued function
definition.
A function definition begins
.B .o
.IR name [@ flag *]
.RI [ name ] ...
followed by line(s) that have the form
.IR term : mask
\&...
.I Name
is either a string or a number.
The first
.I name
following
.B .o
is a symbol of the function
(usually an output pin name or number of a ROM/PAL/FPGA integrated circuit).
Any other
.RI name 's
are symbols of input binary variables.
.I Term
and
.I mask
are decimal numbers.
.PP
There is a correspondence between the bits of the numbers in binary
representation and the input symbols, the first input symbol
is associated with the least significant bit.
The meaning of a bit with value 1 in
.I mask
is `do care',
and the meaning of a bit with value 1 in
.I term
is `input must be 1'.
Thus the
.IR term : mask
is an implicant, and a set of them when
.IR or 'ed
together
describes the input conditions for which the output symbol will have
a value of 1.
.PP
For example:
.EX
 .o 3 1 2
 3:3
 .o 4 1 2
 1:3 2:3 3:3
 .o 5 2 3
 1:3 2:3
 .o 11
 .o 9
 0:0
.EE
Output 3 is the
.I and
function of inputs 1 and 2;
output 4 is the
.I or
function of inputs 1 and 2
.RI ( quine (10.1)
would change this to 1:1 2:2);
output 5 is the
.I exclusive-or
function of inputs 2 and 3;
output 11 is a constant 0 and output 9 is
a constant 1.
.PP
.I Flag
information is essentially communication between
.I lde
and the technology mapper for a particular architecture, and is
passed through unchanged by
.IR quine ,
.IR cover ,
and
.I hazard
(see
.IR quine (10.1)).
Among the 
.I flags
are
.TP
.PD 0
.B b
buried
.TP
.B d
D flip-flop clock
.TP
.B e
output enable
.TP
.B g
clock enable
.TP
.B i
inverted sense
.TP
.B t
T flip-flop clock
.PD
.PP
Another example:
.EX
 .o x0@b
 0:0
 .o x1@b x0
 1:1
 .o x2@b x0 x1
 3:3
 .o x0@t ck
 1:1
 .o x1@t ck
 1:1
 .o x2@t ck
 1:1
 .o c2 x2
 1:1
 .o c2@e en
 1:1
.EE
.B x[012]
are bits of a buried three bit counter, each bit
is toggled by
.B ck
only if all lower bits are 1.
.B c2
outputs
.B x2,
the output enable is
controlled by
.B ck.
.SH SEE ALSO
.IR lde (10.1),
.IR quine (10.1),
.IR cover (10.1),
.IR hazard (10.1),
.IR xpal (10.1),
.IR part (10.1),
.IR act (10.1)