Texas Instruments TI89 Developer Guide - Page 1284

1242 Appendix B: Global Variables - Graphing gr_flags (continued) Assumptions: Access_AMS_Global_Variables is defined. Side Effects: None Availability: On AMS 2.00 and higher. TI-89 / TI-92 Plus None Differences: See Also: None Example: The function below is an example of a TI-BASIC extension function. See section 7.3.2 TI-BASIC Extensions for more information on extensions. void graphsin( void ) /* Return on the estack a list of all the values of sin that would be graphed with the current Window variables in function mode, or if called during graphing, return only the value of sin for the input. */ { Access_AMS_Global_Variables; BCD16 val, num; USHORT ctr; EStackIndex k, old_top = top_estack; if( gr_flags.gr_in_progress == TRUE ) { /* graph in progress - return only one value to plot */ push_approx( top_estack ); /* simplify the input to the function */ if( ESTACK(top_estack) != FLOAT_TAG ) ER_throw( ER_DOMAIN ); val = sin( estack_to_float( top_estack ) ); top_estack = old_top; /* remove simplified input */ push_Float( val ); /* leave result on estack */ return; } /* Not graphing, ignore any input on estack, return list of sin values that would be graphed */ if( gr_active->graph_mode != GR_FUNC ) ER_throw( ER_GRAPH_MODE ); /* must be function mode to access xres */ push_quantum( END_TAG ); for( ctr=0; ctr xmaxpix; ctr += (USHORT)((gr_active->rngp)[GR_XRES] )) { num = (gr_active->rngp)[GR_XMIN] + ((gr_active->rngp)[GR_DELTAX] ) * ctr; /* next input */ val = sin( num ); /* next result */ push_Float( val ); /* build list on estack */ } k = top_estack; /* point to last sin value */ push_reversed_tail (k); /* reverse the order */ delete_between (old_top, k); /* delete the old copy */ push_quantum (LIST_TAG); /* make it a list */ } TI-89 / TI-92 Plus Developer Guide Not for Distribution Beta Version January 26, 2001