AppleWin Debugger Cheat Sheet

The debugger built into AppleWin is extremely handy when figuring out how bits of code work. This is a quick guide to the essentials for people who have some familiarity with debuggers.

Pause emulation and enter the debugger with F7. You can close the debugger the same way, or use "g [enter]".
There's lots of ways to configure the display. The three most important are:
1. Code display. Type "code [enter]". This gets you a code listing on the left and a bunch of register and softswitch info on the right. (This is the default on entry.)
2. Data display. Type "data [enter]". Switches to a hex dump of memory. The single-step commands still work in this mode.
3. Console display. Type "[enter]" by itself. Useful if you want to read some help text more than 5 lines at a time. Hitting "[enter]" again goes back to the previous mode.
In Code mode, use [space] to single-step, Shift+[space] to continue to the next RTS (or "rts [enter]"), and Ctrl+Space to trace over an instruction (useful if you don't want to trace into a JSR; can also use "p [enter]"). To advance to a specific address (e.g. to skip to the bottom of a loop), use up/down arrows to move the cursor, then Ctrl+Down to trace until that line is reached.
In Data mode, type "m1 <address>" to jump to that address. This also creates a mini-window for data that you can see while in Code mode. Use "m2 <address>" to set a second data mini-window.
Use arrows and PgUp/PgDn to move around. Add Shift and Ctrl to the Page keys to move farther. You can do a monitor-style "<address> L" to position the Code view. If you want to get back to the current instruction, hit [tab].
To peek at the Apple II display, use '\ [enter]' to see the current display, and hit a key to go back. There are commands for specific screens, e.g. "hgr" shows hi-res page 1. Use "help view" to list the full set of possibilities.
Set values like you would in the monitor: "800: 52" sets $800 to $52. Does not work for I/O locations like $C050 -- use "out <address> <value>" instead.
Breakpoints:
1. Set an execution breakpoint with "bpx <address>".
2. Set a memory breakpoint with "bpm <address>".
3. Disable and re-enable breakpoints with "bpd <num>" and "bpe <num>".
4. Clear breakpoints with "bpc <num>", where "num" may be "*" to clear everything.
The F1 help talks about conditional breakpoints, but the in-debugger help doesn't seem to.
When in doubt, go into Console mode and type "help". There's a bunch of stuff in the console help text that isn't in the F1 help file. Some useful things to look at:
- "help mem" will tell you how to load/save chunks of memory, move data around, and search for values.
- "help r" explains how to modify register contents.
To see how many cycles a piece of code takes to execute, set breakpoints at the start and end with "bpx". When you break at the entry point, type "profile" to reset the profile counters, then continue. At the exit point, hit Enter to go into full-screen command output mode, then type "profile list" to see the cycle count summary.

Other notes:

Sometimes when switching display modes, the left area will be blank (e.g. if you're in Console display mode and type "code"). Just type the desired mode again.
Some more stuff from Michael "AppleWin Debugger" Dev: comp.sys.apple2.

Things I haven't figured out yet:

How to single-step while watching the Apple II screen.

(Emulator v1.29.3.0, debugger v2.9.0.15)