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OTHER SYSTEM FUNCTIONS
27.2 -- Double-byte Arithmetic Functions
left as the shift takes place.
27.2.4
Shift memory left --
.MMA
The
.MMA
function shifts the contents of a double byte
in memory
to
the
left
by
the
number
o~
bit
positions
re~resented
by
the contents of
th~
A
register.
The e¥fect is
to. multiply the double byte by a power of 2.
The exponent is
given
by
the value of the
A
register.
ENTRY PARAMETERS:
EXIT CONDITIONS:
x
=
The
address
of the most significant
byte of a double byte in
memor~.
A
is
unchanged.
B
is unchanged.
X
is
unchanged.
CC
is
indeterminate.
The
double
byte
in
memory
has
been
shifted
to the left
by
the number
Or
bits represented by the
contents
of
A.
Zero bits are brought in from the
l'
i
g
h
t
a s
t
h.
e
s
h i f
t t
a
k
e s
pia c e.
27.3 Character
St~ing
Functions
The character string functions are used by some
of
the
more
complex system functions and the MDOS commands as macro
instructions or subroutines.
27.3. 1
String move -- .
MOVE
The .
MOVE function
transfers
a
series
of
contiguous
bytes in memory from one location into another location.
The
move is made starting with the lowest addressed byte
of
the
source string.
ENTRY
PARAMETERS:
B = The
number of bytes to be moved.
Ir
B is
intially
zero.
256
(decimal)
bytes will be moved."
X
=
The
address
Or
the first byte
o~
a
four-byte
parameter
packet.
The
parameter
packet
has
the following
format:
/
Page
27-08
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