Basic Disk Operating System (BDOS) Functions
4-38
PROGRAM
LOAD
ENTRY
RETURN
CL: 3BH
FUNCTION
59
DX: Offset
ofFCB
PROGRAM
LOAD
AX: Return
Code/
Base Page Addr
BX:
Base Page
Addr
The
Program
Load
function-loads a
CMD
file. Register
DX
contains the DS
relative offset
of
a successfully opened FCB which names the
input
CMD
file. AX
returns the value
OFFH if the
program
load was unsuccessful. Otherwise,
AX
and
BX
both
contain the
paragraph
address
of
the base page belonging
to
the loaded
program. The base address
and
segment length
of
each segment are stored in the
base page.
NOTE
Upon
program
load
at
the
CCP
level, the
DMA
base address
is
initialized
to
the base
page
of
the loaded program
and
the
DMA
offset adddress
is
initialized
to
0080H. This
is
a
function
of
the CCP. Function
59
does not
establish a default
DMA
address.
It
is
the
responsibiiity
of
the program which executes
function 59
to
also execute function
51
to
set
the
DMA
base,
and
function 26 to set the
DMA
offset before passing control
to
the
loaded program.
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