Apple II manual ATN Implementation, Entered by Alter Memory M, OF9C, 0FAC, 0FBD A5 LDA 0FBF 48 PHA

observed:

When BASIC stores a program on cassette, it inserts a CTRL/Z after the last line. The AIM 65 Editor will strip off the CTRL/Z when it retrieves the program. Therefore, before storing a BASIC program from the Editor, the user must insert a CTRL/Z following the last line of the program.

H ATN IMPLEMENTATION

The ATN function (see Subject 307) can be programmed in RAM using the AIM 65 Mnemonic Entry (I) and Alter Memory Locations (/) commands, as shown below. The program is written

for the AIM		65	with	4K	bytes of RAM. The ATN function can be relocated elsewhere in memory
by changing		the	starting addresses of the instructions and constants, the conditional branch
addresses, the			vector to the constants start address and the vector to the ATN function starT
address.
ATN FUNCTION CONSTANTS					ENTERED BY ALTER MEMORY <M>
<M> = 0F80		XX	XX	XX	XX	Constants Starting Address = 0F80
</> = 0F80		0B	76	83	83	8
</>	0F84	BD	D3	79	1E
</>	0F88	F4	A6	F5	7B
</>	0F8C	83	FC	B0	10
</>	0F90	7C	0C	1F	67
</>	0F94	CA	7C	DE	53
</>	0F98	CB	C1	7D	14
</>	OF9C	64	70	4C	7D
</>	0FA0	B7	EA	51.	7A
</>	0FA4	7D	63	30	88
</>	0FA8	7E	7E	92	44
</>	0FAC	99	3A	7E	4C
</>	0FR0	CC	91	C7	7F
</>	0FB4	AA	AA	AA	13
</>	0FR8	81	00	00	00
</>	0FBC	00
ATN FUNCTION INSTRUCTIONS STORED BY MNEMONIC ENTRY (I)
<I>
XXXX *=0FBD						Instructions Starting Address = 0F8D
0FBD A5 LDA		AE
0FBF 48 PHA
0FC0 10 BPL		0FC5
0FC2 20 JSR		CCB8
0FC5 AS LDA		A9
0FC7 48 PHA
0FC8 C9 CMP		#81
0FCA 90 BCC		0FD3
0FCC A9 LDA		#FB
0FCE A0 LDY		#C6
0FD0 20 JSR		C84E
0FD3 A9 LDA		#80	\			Starting Address of Constants = 0F80
0FD5 A0 LDY		#0F	/
0FD7 20 JSR		CD44
0FDA 68 PLA
0FDB C9 CMP		#81
0FDD 90 BCC		0FE6
0FDF A9 LDA		#4E
0FE1 A0 LDY		#CE
0FE3 20 JSR		C58F
0FE6 68 PLA
0FE7 10 BPL		0FEC
0FE9 4C JMP		CCB8
0FEC 60 RTS
0FEC

BASIC INITIALIZATION FOR ATN FUNCTION

BASIC memory must be initialized below the memory allocated to the ATN function. The ATN vector in RAM must also be changed from the address of the FC error message to the starting