Two-byte program instructions, Memory requirements for the advanced functions – HP 15c User Manual
Page 219
Appendix C: Memory Allocation 219
For _ and f, allocation and deallocation of the required register
space takes place automatically.
*
Memory is thereby allocated only for the
duration of these operations.
Space for the imaginary stack is allocated whenever ´ V, ´
}, or | F 8 is pressed. The imaginary stack is deallocated when
" 8 is executed.
Space for matrix registers is not allocated until you dimension it (using
m). Reallocation takes place when you redimension a matrix. >
0 dimensions all matrices to 0
0.
*
If you should interrupt a _ or f routine in progress by pressing a key, you could deallocate its
registers by pressing |n or ´ CLEAR M in Run mode.