Back in the 1990s, I bought a copy of Devpac for my Amiga A500, but for some strange reason I never got very far with it. I remember reading a book about 68000 Assembly Language with a light blue and yellow cover, as well as the Amiga Hardware Manual and various magazine articles.
I'm currently using an A1200 with 10Mb RAM with Kickstart 3.0 (V39) and Workbench 3.0. A few days ago, I asked Chat GPT to create an Assembly Language program for the Amiga using Devpac syntax which prints out a message 20 times. This program is listed below. As expected, it generated several errors. I managed to debug all but two of these errors, which were using the syntax 0x to indicate Hexadecimal numbers. I just deleted the 0x, but now I think I should probably type $ to replace these before I can get the program to compile.
There are another two errors which I can't debug, in spite of reading the relevant section of the manual, though. This is the SECTION directive, used three times in this program. It seems to be essential for certain types of data, otherwise different errors are generated, such as "not defined". I solved the problem with the first use of SECTION, by changing it to SECTION TEXT, TEXT but the usage of TEXT before the comma can't be repeated for the other two occurrences of SECTION, otherwise it causes errors. TEXT1, TEXT2, and TEXT3 can't be used without causing errors either. All other names I've tried cause errors as well. Can someone debug this for me? I've pasted the original version below without my corrections of deleting all occurrences of 0x, and inserting a $ in front of a clearly Hexadecimal number. Of course, this program could be easily written in C, but I'm trying to learn more about 68000 Assembly Language.
Amiga Assembler Print Message 20 Times in Devpac with key press required after each time
SECTION Text, CODE
start:
; Initialize system
move.l #0,-(sp) ; Clear stack pointer
move.w #$4e75,sr ; Clear interrupts
move.l #$2,A6 ; Set up supervisor stack
jsr -198(A6) ; Open graphics library
move.l d0,GraphicsBase ; Save graphics library base
; Open graphics screen
move.l #640,d0 ; Screen width
move.l #200,d1 ; Screen height
move.l #0,d2 ; Display mode (0 for default)
move.l #3,d3 ; Bitplanes (3 for 8-bit color)
jsr -90(A6) ; Open screen
move.l d0,Screen ; Save screen pointer
; Get screen bitmap
move.l Screen.w,d0 ; Get screen pointer
move.l d0,d1 ; Save screen pointer
; Clear screen
move.l Screen,d0 ; Get screen pointer
moveq #0,d1
moveq #128,d2
move.l d0,d3
jsr -126(A6) ; Clear display
; Set up font
move.l d1,d0 ; Get screen pointer
jsr -132(A6) ; Open font library
move.l d0,FontBase ; Save font library base
; Set up text color
move.l #2,d1 ; Text color (2 for yellow)
; Loop to print message 20 times
moveq #0,d0
print_loop:
move.l #TextPos,d0 ; Text position
jsr -0x80(A6) ; Set up text position
; Print message
lea Message(pc),a0 ; Load address of message
jsr -0xc6(A6) ; Print text
; Wait for a key press
jsr -0x132(A6) ; Wait for a key press
; Increment loop counter
addq.l #1,d0
cmp.l #20,d0 ; Check if printed 20 times
bne print_loop ; If not, loop back to print more
; Close font library
move.l FontBase,A6
jsr -138(A6) ; Close font library
; Close graphics screen
move.l Screen.w,d0 ; Get screen pointer
move.l d0,d1 ; Save screen pointer
move.l d1,d0 ; Get screen pointer
jsr -96(A6) ; Close screen
; Close graphics library
move.l GraphicsBase,A6
jsr -0x102(A6) ; Close graphics library
; Terminate program
moveq #0,d0
moveq #0,d1
move.w #0x4e75,sr ; Return to Workbench
SECTION Data, DATA
Message:
DC.B "Hello, Amiga World!",0
SECTION BSS, DATA
Screen:
DS.L 1
FontBase:
DS.L 1
GraphicsBase:
DS.L 1
TextPos:
DS.L 2
