Commodore Plus 4 - Page 379

The Datassette Tape Recorder 367
4. Check for errors by checking the carry status and the status variable. The status
variable can be loaded into .A with READSS ($FFB7).
Example: This example does a relocated load of the file created in the previous example.
Device number of the Datassette.
Signal a relocated load.
SETLFS.
Length of the file name.
Low byte of address of the file name.
High byte of address of the file name.
SETNAM.
Signal load.
Low byte of the load address.
High byte of the load address.
LOADSP.
Carry set indicates error.
Read the status byte.
If an error is detected, send out
message.
Stop processing.
This routine sends the word ERROR to the screen:
2080 A2 06 LDX #$06 Length of the word.
S082 BD F8 20 LDA $20F8,X Get a character of the message.
2085 20 D2 FP JSR $FFD2 Send to the screen.
2088 CA DEX Decrement the count.
2089 10 F7 BPL $2082 If not done, continue.
. 2000
. soos
. 2004
. 2007
. S009
. 200B
. 200D
. 2010
. 2012
. 2014
. 2016
. 2019
. 201B
. 201E
. 2020
A2
AO
20
A9
A2
AO
20
A9
A2
AO
20
BO
20
DO
00
01
00
BA
06
00
21
BD
00
00
30
D5
65
B7
60
FF
PF
FF
FF
LDX
LDY
JSR
LDA
LDX
LDY
JSR
LDA
LDX
LDY
JSR
BCS
JSR
BITE
BRK
#$01
#$oo
$FFBA
#$06
#$oo
#$21
$FFBD
#$oo
#$oo
#$30
$FFD5
$2080
$FFB7
$2080
208B 00
BRK
Stop processing.
>20F8 52 4F 52 52 45 OD 20 20
>2100 53 41 56 50 52 47 00 00
Verify
When a file is to be verified against memory, the file name by which it is known on
the tape may be stored in CHR$ codes in ascending order somewhere in memory.
If it is omitted, the first file found on the tape is used. The following outlines the
operations required:
1. Load .X with $01 (the device number of the Datassette). Load .Y with $00 for a
relocated verify, or a nonzero value for a nonrelocated verify. This flag is