Texas Instruments TI-89 Developer's Guide

Appendix A: System Routines — Logic
735
TI
-
89 / TI
-
92 Plus Developer Guide
Not for Distribution
Beta Version January 26, 2001
is_undefined
Declaration:
Boolean
is_undefined
(EStackIndex
k
)
Category(ies):
Logic
Description:
Determines whether the real and/or imaginary part of the expression
indexed by
k
is an UNDEFINED_TAG.
Inputs:
i
— Indexes the top tag of an internally-simplified Algebraic expression.
Outputs:
Returns TRUE if the real and/or imaginary part of the expression indexed
by
k
is UNDEFINED_TAG. Otherwise returns FALSE.
Assumptions:
None
Side Effects:
None
Availability:
On AMS 2.04 and higher.
TI
-
89 / TI
-
92 Plus
Differences:
None
See Also: is_float_signed_infinity, is_float_infinity,
is_float_unsigned_inf_or_nan, is_float_transfinite, is_nan
Example:
push1();
real_part = top_estack;
push_quantum (UNDEFINED_TAG);
replace_top2_with_imre (real_part);
is_undefined (top_estack); /* Returns TRUE */

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