of Microprocessors

SOME REAL ApPLICATIONS 747
used by the synthesis routines and is usually 1,024 entries. Options can also
be specified on the command line, in which case they override those in the
score.
At this point, it is probably better to describe the norelist, which is the
actual score, first. The most fundamental notelist statement is the NOTE
statement. It consists simply of the keyword NOTE followed by several
parameter or "P-fields," each separated from the others by blanks. PI is the
keyword "NOTE" itself, while P2 is the "acrion time" and P3 is rhe name of
the instrument that will play the note. The action time specifies when the
note should start and is normally given in seconds. P4 is the duration of the
note, also given in seconds, and is the last required parameter. Additional P­
fields may be used if the instrument that will play the note requires them. By
convention, P5 usually gives the amplitude and P6 the frequency of pitched
notes. As many P-fields as desired may be used according to the complexity
of the' corresponding instrument definitions. Below are a few valid note
statements in their simplest form:
NOTE 0.00 BLATT
NOTE 0.15 BLEEP
NOTE 0.20 BUPP
NOTE 0.50 BLOPP
NOTE 1.25 BLURP
.10
. 15
.05
.35
.25
1.0 16
.707 220HZ
- 3DB 4*261HZ
- SOB 1.5KHZ
ODB 55HZ V5
Two octaves above1
{ middle C J
5.7HZ 0.2SEC
3*V7 + 2
The first note is played on an instrument c'alled BLATT starting
immediately at time zero and lasting for one-tenth of a second. Its amplitude
is unity (the maximum amplitude allowable in C-MUSIC) and the frequency
is 256 Hz. Actually, the frequency field gives the waveform table pointer
increment value; thus, the wave frequency is actually P6*SR/FL, where P6 is
the given P6 field value of 16, SR is the sample rate (default is 16,384 Hz),
and FL is the wavetable or function length (default is 1024). The second note
is similar but the "postop" hertz is used so that frequency can be specified in
hertz rather than wavetable increments. Needless to say, this is usually done.
The third note illustrates the decibel postop, which is useful in amplitude
specification and the fact that arithmetic expressions can be used in
specifying P-field values. In fact, nearly any kind of expression normally
permitted in a programming language including functions such as SIN,
COS, LN, EXP, SQRT, and even RAND can be used. In the fourth note, the
"K" postop, which is a 1024 multiplier, is also included in the frequency
specification to yield 1,536 Hz. Two additional parametets needed by the
BLOPP instrument are also included. The SEC postop converts the given
number, which is a waveform period here, into an increment. The last note
makes use of variables in expressions for its P7 and P8 fields. V5 and V7 have