Radio Shack TRS-80 Owner's Manual page 104

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Exit
Conditions
None
Sample Use
CALL
4SYSRTN
5
ANY SYSTEM ROUTINE
JR
Z.OKGO
5
CHECK FOR ERROR
5
THE
FOLLOWING INSTRUCTION
SETS BIT
G
(DETAILED
!
ERROR MESSAGE) AND BIT
7
(RETURN
TO
CALLER AFTER
!
DISPLAYING MESSAGE
OR C0H
5
BINARY 11000000
CALL $ERRDSP
!
NOW CALL ERROR DISPLAY
5
CONTINUE HERE UPON RETURN FROM ERROR DISPLAY
i
YOUR ERROR HANDLER MAY
GO HERE
5
:
5
:
j
;
OKGO ICONTINUATION AFTER $SYSRTN WITH
NO
ERROR
$DSPDIR^
17433/X'4419'
This
command
displays the directory
listing
of
all
non-protected user
files
in a
specified drive.
Entry Conditions
(X'427i')
=
ASCII-coded drive
number
"0," "1," "2,"
or
"3"
CALL
SDSPDIR
Exit Conditions
All registers are
changed.
$COMDOS
—
17049/X'4299'
This
routine
executes
a
trsdos
command
and
returns
to
trsdos
ready.
Entry Conditions
(HL)
=
Text of
trsdos command,
terminated
by
x'od:
JP
SCOMDOS
Exit
Conditions
None
88