Time Stretching

Time Stretching – initial

TIMESTRETCH

If this option is checked, DxWnd tries to emulate an accelerated (xn) or decelerated (:n) time flow. The value set in the listbox is the initial value, that can be altered by means of the time control slider in the time panel. When checked, DxWnd stretches time in timing API such as GetSystemTime(), the query performance APIs and the Sleep APIs, that are the most used ways to control a program timing.

Show time stretch

SHOWTIMESTRETCH

When checked, the time stretch ratio is drawn as an overlay of the program client area, in a corner of the screen and periodically and randomly moved to other cornes whenever it is updated.

Fine time adjust

FINETIMING

When checked, the time stretch ratio coarse becomes finer, from a 1.5 (50%)ratio to a 1.1 (10%) ratio for each tick. This allows a better and finer control of timing, despite the more limited range (about 0.5x up to 2.0x).

Intercept RDTSC opcode

INTERCEPTRDTSC

Program timing is usually determined by system calls that can be easily and safely hooked to stretch the flow of time. There is one possible exception, however: when the program embeds in its assembly the RDTSC assembly instruction opcodes that directly access the hardware clock. This timing value can still be intercepted and manipulated, but using a more delicate technique that is searching for the assembly code and replacing it with specific calls. This is why I preferred to leave this possibility with a dedicated flag to be activated when necessary. The flag should be set whenever adjusting the time stretching option does not alter the time flow.

Stretch timers

STRETCHTIMERS

When checked, the window timers are stretched, namely the user32.dll timers set by SetTimer and the multimiedia timers in winmm.dll set by timeSetEvent().