Texas Instruments TI-89 Developer's Guide

500
Appendix A: System Routines — EStack Arithmetic
TI
-
89 / TI
-
92 Plus Developer Guide
Not for Distribution
Beta Version January 26, 2001
push_ratio
Declaration:
void
push_ratio
(EStackIndex
i
, EStackIndex
j
)
Category(ies):
EStack Arithmetic
Description:
Pushes onto the estack the internally-simplified ratio of expression
i
divided
by expression
j
.
Inputs:
i, j
— Indexes to top tags of internally-simplified algebraic expressions,
algebraic comparisons, or aggregates thereof.
Outputs:
None
Assumptions:
None
Side Effects:
None
Availability:
On AMS 2.02 and higher.
TI
-
89 / TI
-
92 Plus
Differences:
None
See Also: divide_top, replace_top2_with_ratio, push_reciprocal,
replace_top_with_reciprocal
Example:
EStackIndex index_push_monic_or_prim_pair (EStackIndex i, EStackIndex j)
/* If i indexes a Float, pushes 1.0 then the ratio of expressions j and i.
Otherwise pushes i/gcd(i,j) then j/gcd(i,j).
In either case, returns the index of the deeper pushed value.
*/
{ Access_AMS_Global_Variables;
EStackIndex k;
if (FLOAT_TAG == ESTACK (i))
{ push_expression (Float1Index);
k = top_estack;
push_ratio (j, i);
}
else
{ EStackIndex old_top = top_estack;
EStackDisplacement del =
deleted_between (old_top, push_gcd_then_cofactors (j, i, &k));
k -= del;
}
return k;
}

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