Execution tracing for call graph generation

No need to hunt with this secret link.

As for MSX1s with disk drive, I think you can try the National CF-3300. As for PAL systems, I don’t know, you could browse the MSX1 category of the wiki further and check the specs of the MSX1 machines, or plug in a disk drive extension cartridge, or pick an MSX2 machine like the Philips NMS 8245.

THe VY-0010 is a single sided drive. Try the Sony HBD-F1 instead. There wasn't any European MSX1 with a double sided disk drive. Why not try an MSX2 like the Philips NMS 8245?

AFAIK that demo (Bold) also exists in ROM format. So that's also an alternative.

By the way, by following your link and clicking download, I got to the dvik/joyrex website, but I can't download anything there (anymore). Does that work for you?

Sounds neat, I’d be interested in seeing some examples of those graphs and tools .

You already tried the openMSX debugger as well? It doesn't contain the functionality you are talking about, but it may still be useful. You can also step back one instruction, which may be useful as well.

Here is a very basic starting point:

namespace eval call_graph {

set_help_text call_graph \
{Builds a call graph of functions used in the running code.}

variable log_file

proc check_call {} {
	set address [reg PC]
    set instr [peek $address]
    expr {$instr == 0xCD || $instr & 0xC7 == 0xC4}
}

proc log_call {} {
	variable log_file
	if {![info exists log_file]} return
    set from [reg PC]
    set to [peek16 [expr {$from + 1}]]
	puts $log_file [format "%x %x" $from $to]
}

proc call_graph {filename} {
	variable log_file
	set log_file [open $filename {WRONLY TRUNC CREAT}]
	debug set_condition {[call_graph::check_call]} {call_graph::log_call}
	return ""
}

namespace export call_graph

} ;# namespace call_log

namespace import call_graph::*

Right now it just logs every call instruction with the source and destination of the call. Even this very basic code is enough to do some interesting analysis though. For example:

jblang@cloud9:~/winhome/Retro/MSX/openmsx$ awk '{print $2}' calls | sort | uniq -c | sort -n | tail -10
   1033 167e
   1033 168a
   1033 1941
   1034 153
   1034 1eec
   2207 1813
   3099 155a
   3102 4b7
   5300 2f43
  53009 1137

This gives a list of the 10 most frequently called subroutines while a certain section of the demo is running. When inspecting disassembled code, I find it is best to start with frequently used utility subroutines and understand what they do, which provides context for better understanding the functions that are calling them. So now I know I should probably investigate what functions at address 1137 and 2f43 do first in order to understand this part of the demo better.