Self-Modifying code for user settings optimization

Jason Jeffory via Digitalmars-d digitalmars-d at
Sat Jan 9 02:31:03 PST 2016

Instead of something like


Which requires an access to UserSettings, which may be slow in 
time critical code(but you want to provide some way to configure 
various behaviors), why not use self-modifying code?

DoSomething(3); // 3 maybe the default, but a hack is somehow 
introduced, such as modifying the "push 3" instruction to "push 
width" (but width is constant for all runs, the instruction 
itself changes values only when the default value is 
changed(could be done at setup). (push could be mov or whatever)

This would avoid pipelining issue and provide the absolute fasted 
way to have settings?

(Of course, we'd have to know where all the "push" instructions 
are located and all that since the modification could not occur 
serially(would be somewhat pointless then))

Not even sure if CPU's allow SMC anymore?

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