app.gel

来自「DSP体系结构实现与应用源代码」· GEL 代码 · 共 30 行

/*
 *  This GEL script simulates user input/output; there is one switch
 *  (selection of which channel will be output), and two sliders 
 *  (volume gain for each channel). A "switch" is implemented as a
 *  slider that goes from 0 to 1 in steps of 1. On the target, a procedure
 *  periodically runs that checks these values, which simulate a part
 *  of the I/O space.
 *
 *  Each control writes a value in the simulated device controls' IO area,
 *  i.e. in the target's array called deviceControlsIOArea[1 + 1 + NUMCHANNELS].
 *  Element[0] indicates whether there has been any user input 
 *  Element[1] is the number of the channel that should be used for the
 *  output, and [2 + i] is the volume for channel i.
 *  When the script changes any of the values, it also sets element [0]
 *  to non-zero, and indication for the thread on the target that there
 *  has been new user input.
 */

menuitem "Application control";

/* 
 *  Slider "set channel 0 gain" goes from 0 to 200, where 100 is the default,
 *  in increments of 1 and "page increments" of 10. 
 */
slider Set_channel_0_gain(0, 200, 1, 10, c0gain)
{
    deviceControlsIOArea[2] = c0gain; /* set gain for channel 0 */
    deviceControlsIOArea[0] = 1;      /* indicate new user input */
}