Texas Instruments TI-89 Developer's Manual page 870

828
Appendix A: System Routines — Math
push_shift
(continued)
Example:
If m indexes the bolded tag in the integer 256 (0b100000000) as follows
0 1 2 NONNEGATIVE_INTEGER_TAG
and n indexes the bolded tag in the integer one as follows
1 1 NONNEGATIVE_INTEGER_TAG
then
push_shift (m, n);
pushes 512 (0b1000000000) onto the estack such that top_estack points to the bolded tag as
follows.
0 2 2 NONNEGATIVE_INTEGER_TAG
If m indexes the bolded tag in the list {a, b, c} as follows
END_TAG C_VAR_TAG B_VAR_TAG A_VAR_TAG LIST_TAG
and n indexes the bolded tag in the integer –1 as follows
1 1 NEGATIVE_INTEGER_TAG
then
push_shift (m, n);
pushes the right shifted list {undef, a, b} onto the estack such that top_estack points to the
bolded tag as follows.
END_TAG B_VAR_TAG A_VAR_TAG UNDEFINED_TAG LIST_TAG
If m indexes the bolded tag in the string "hello" as follows
0 h e l l o 0 STR_DATA_TAG
and n indexes the bolded tag in the floating-point number 3. as follows
0x40 0x00 0x30 0x00 0x00 0x00 0x00 0x00 0x00 FLOAT_TAG
then
push_shift (m, n);
pushes the left shifted string "lo " onto the estack such that top_estack points to the bolded
tag as follows.
0 l o ï ï ï 0 STR_DATA_TAG
TI-89 / TI-92 Plus Developer Guide Not for Distribution Beta Version January 26, 2001