Internal emulation of simple commands (Options|Run trace|Allow fast command emulation) has made run and hit trace 15 (fifteen!) times faster. On my Athlon 4000+, standard run trace executes 35000 commands per second. With the emulation on, OllyDbg traces 500000 commands! For simple programs, this may be close to the real-time execution - in the step-by-step mode, with the full protocolling. Emulation covers only the small subset of 80x86 commands - moves, PUSH/POP, arithmetical and boolean operations, comparisons, shifts, jumps, calls, returns and LEAs. No multiplications, prefixes, loops or string operations, no FPU or MMX; still, OllyDbg passes to the application less than two percents of commands. Frequently one uses run trace together with the run trace condition, like: "stop trace when EAX==0x123456". Up to now, the inetrpreter parsed conditional expression on each step. However, this was too slow for the accelerated trace. Now I compile expressions to the simple pseudocode and use a very quick interpreter to estimate the condition. As a result, the above comparison is processed in only 130 nanoseconds. Not bad! Oh yes, and command help now includes the string commands, too.
