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         GSplus

Modern cross-platform Apple IIgs emulator and tools based on KEGS

Manual Versions:  Alpha Draft: 2016-10-27,  Initial Draft: 2016-05-01

Overview & Purpose
This project is an attempt to build a better Apple IIgs emulator by modernizing the KEGS/GSport emulator family and extending it into a platform.
The first steps were a release of a new SDL2 driver.  SDL or "Simple DirectMedia Layer" enables the writing of one cross-platform driver to handle input and output (video, mouse, keyboard, audio, joystick).  This helps the goal of providing first-class support for all of the major platforms supported by SDL, including Mac OSX, Windows and Linux.
Part of this effort has also led to the development of an automated build and packaging pipeline using Gitlab CI.  This helps our team of one continue to develop on primarily a single platform, while still ensuring that it works across many operating systems
Currently, the main supported platforms are Linux, OSX and *Windows.  *Unfortunately the SDL2 version of Windows is not done as of this draft, but the Win32 API version still works well and is regularly built, though missing some features like screenshots.

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Getting started
1. Download the emulator package and put it in a folder
2. Download the Apple IIgs Firmware ROMs, for either a ROM01 or ROM03 machine.  (If you have a real IIgs, there are ways to save it from your machine as well.)
3. Download some Apple IIgs software.
   1. I recommend the excellent Apple IIgs dedicated site, http://www.whatisthe2gs.apple2.org.za/
   2. If you have a real IIgs, you can transfer your disks using ADTPro http://adtpro.sourceforge.net/
1. Edit your config:
   1. You can manually edit the config.txt file  … OR ...
   2. While the emulator is running… hit F4 to enter config menu.
1. Boot the Apple IIgs by running the emulator
   1. Windows:      gsplus.exe
   2. Mac/Ubuntu:   ./gsplus

Emulator Hot-Keys
There are several keys used to interact with the emulator while it is running.  Here’s a quick list of the main hot-keys and what they do.
F4         - Configuration menu
F5         - Config menu
F6         - Toggle System Speed  (1, 2.8, 8, ∞ MHz )
F7         - Toggle Fast Disk Emulation
F9         - Invert Paddles
F10         - Toggle a2vid_palette (?)
F11         - Toggle Fullscreen Mode
F12         - RESET Key (so to hit “Ctrl-Reset” on an Apple II, you hit “Ctrl-F12”)
SHIFT+F5         - Screenshot

Other Input/Output
1. Mouse and keyboard should automatically work
2. Joystick with SDL2 driver is known to be working.  It simply uses the “first” joystick and the first analog pad on that stick plus the first two buttons.  The axes and buttons are not yet configurable.  Better info forthcoming.
3. There are drivers for serial controller, ImageWriter (II?) printer, and networking.  I may have broken some of this functionality to get builds working.  I’m not currently familiar with the state of these drivers or their usage.  More info will be added as I take time to research more of the modules.

Configuration Menu
Configuration options are loaded from, and saved to, a configuration text file.  The default configuration file is config.txt.  If you are just starting out, it’s recommended to use the configuration menu versus editing the file yourself.
Enter the configuration menu at any time while running GSplus by hitting <F4>.

Most importantly, you can use the Disk Configuration menu option to “mount” and “eject” disks.
Command-line Options
This is from source, some are experimental and not all may be built on your system.
-badrd                        Halt on bad reads
-noignbadacc        Don’t ignore bad memory accesses
-noignhalt                Don’t ignore code red halts
-test                        Allow testing
-hpdev                 Use /dev/audio (HP/UX?)
-alib                         Use Aserver audio server
-24                         Use 24-bit display depth
-16                         Use 16-bit display depth
-15                         Use 15-bit display depth
-bw                        Force B/W modes
-joystick                Ignore joystick option
-noshm                Don’t use X shared memory
-dhr140                Use simple double-hires color map
-mem value                Set memory size to value
-skip value                Set skip_amt to value
-audio value                  Set audio enable to value
-arate value                Set preferred audio rate to value
-v value                 Set verbose flags to value
-display value                Set X-Windows DISPLAY=value
-enet value                Set ethernet to value
-config value                Set config file to value
-debugport value        Set debugport to value
Note: The final argument, if not a flag, will be tried as a mountable device.






Debugger Commands
Enter from the debugger prompt (Shift-F6)
GSplus CLI Debugger help (courtesy Fredric Devernay)
General command syntax: [bank]/[address][command]
e.g. 'e1/0010B' to set a breakpoint at the interrupt jump pt
Enter all addresses using lower-case.  As with the IIgs monitor, you can omit the bank number after having set it: 'e1/0010B' followed by '14B' will set breakpoints at e1/0010 and e1/0014


g                                   Go
[bank]/[addr]g                      Go from [bank]/[address]
s                                   Step one instruction
[bank]/[addr]s                      Step one instr at [bank]/[address]
[bank]/[addr]B                      Set breakpoint at [bank]/[address]
B                                   Show all breakpoints
[bank]/[addr]D                      Delete breakpoint at [bank]/[address]
[bank]/[addr1].[addr2]              View memory
[bank]/[addr]L                      Disassemble memory
P                                   Dump the trace to 'pc_log_out'
Z                                   Dump SCC state
I                                   Dump IWM state
[drive].[track]I                    Dump IWM state
E                                   Dump Ensoniq state
[osc]E                              Dump oscillator [osc] state
R                                   Dump dtime array and events
T                                   Show toolbox log
[bank]/[addr]T                      Dump tools using ptr [bank]/[addr] as 'tool_set_info'
[mode]V                             XOR verbose with 1=DISK, 2=IRQ,4=CLK,8=SHADOW,10=IWM,20=DOC,
                                      40=ABD,80=SCC, 100=TEST, 200=VIDEO
[mode]H                             XOR halt_on with 1=SCAN_INT,2=IRQ, 4=SHADOW_REG, 8=C70D_WRITES
r                                   Reset
[0/1]=m                             Changes m bit for l listings
[0/1]=x                             Changes x bit for l listings
[t]=z                               Stops at absolute time t (obsolete)
S                                   show_bankptr_bank0 & smartport errs
P                                   show_pmhz
A                                   show_a2_line_stuff show_adb_log
Ctrl-e                              Dump registers
[bank]/[addr1].[addr2]us[file]      Save mem area to [file]
[bank]/[addr1].[addr2]ul[file]      Load mem area from [file]
v                                   Show video information
q                                   Exit Debugger (and GSplus)


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Project Info
Developers inquire within  :P
Main page and full source code repository: https://github.com/digarok/gsplus
This project has an ugly unmaintained homepage at http://apple2.gs/plus/
