15 is an emulator for the Atari 2600.
16 It exectues the romfile given as an argument,
17 and controls as if using a regular 4-direction 1-button joystick,
18 using \fBspace\fR button and directional keys.
19 The \fBq\fR, \fBw\fR, \fBe\fR and \fBr\fR keys correspond respectively to the reset, select, player 1 difficulty and color mode switches.
23 Pause the emulator. If already paused it will step one video frame.
26 Toggle the emulator's speedometer. It shows in the upper left,
27 off-viewport corner, the ratio between the expected and observed time it
28 took to draw 60 frames.
31 Toggle tracing of the emulator.
34 It uncaps the 60fps frame rate and lets emulation go as fast as possible.
48 Scale the screen to a given factor regardless of the window's size.
50 .B /sys/src/games/2600
55 first appeared in 9front (November, 2014).