Texas Instruments TI-89 Developer's Guide

Appendix A: System Routines — EStack Arithmetic
493
TI
-
89 / TI
-
92 Plus Developer Guide
Not for Distribution
Beta Version January 26, 2001
push_negate
Declaration:
void
push_negate
(EStackIndex
i
)
Category(ies):
EStack Arithmetic
Description:
Pushes onto the estack the internally-simplified negative of the expression
indexed by
i
.
Inputs:
i
— Index of the top tag of an internally-simplified algebraic expression,
algebraic comparison, or aggregate thereof.
Outputs:
None
Assumptions:
None
Side Effects:
None
Availability:
On AMS 2.02 and higher.
TI
-
89 / TI
-
92 Plus
Differences:
None
See Also: negate_top
Example:
Boolean is_symmetric (EStackIndex i, EStackIndex var)
/* Returns TRUE if it can determine that the expression indexed by i is symmetric
with respect to the variable indexed by var. Otherwise returns FALSE.
*/
{ Access_AMS_Global_Variables;
EStackIndex old_top = top_estack;
push_negate (var);
push_substitute_simplify (i, var, top_estack);
subtract_from_top (i);
if (is0 (top_estack))
{ top_estack = old_top;
return TRUE;
}
top_estack = old_top;
return FALSE;
}

Texas Instruments TI-89 Specifications

General

Display size (HxV)	100 x 160 mm
Memory type	639K FLASH ROM, 188K bytes RAM
Compatible operating systems	Operating System 2.09
Battery type	AAA