Texas Instruments TI-89 Developer's Guide

480
Appendix A: System Routines — EStack Arithmetic
TI
-
89 / TI
-
92 Plus Developer Guide
Not for Distribution
Beta Version January 26, 2001
is_minus1
Declaration:
Boolean
is_minus1
(IndexConstQuantum
i
)
Category(ies):
EStack Arithmetic
Description:
Determines whether
i
indexes a tagged big integer
L
1 or tagged float
L
1.
Inputs:
i
— Index of an expression.
Outputs:
Returns TRUE if
i
indexes a tagged big integer
L
1 or tagged float
L
1.
Otherwise returns FALSE.
Assumptions:
i
indexes the top tag of an expression.
Side Effects:
None
Availability:
On AMS 2.02 and higher.
TI
-
89 / TI
-
92 Plus
Differences:
None
See Also: is0, is1
Example:
Boolean is_plus_or_minus_one (IndexConstQuantum i)
/* i indexes an expression. Returns TRUE if the expression is an integer
or Float 1 or -1. Otherwise returns FALSE.
*/
{ return is1 (i) || is_minus1 (i);
}

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