The EL-512H is a recent programmable calculator from Sharp. Unlike some other models like the EL-5020, this calculator has true program capability, including the ability to execute instructions conditionally or implement simple loops.

In the absence of a visible step number or user-defined labels, an interesting, innovative solution was used for loops. The \(\hookrightarrow\) key is used to mark the beginning of a loop; later in the program, the \(\Lsh\) key is used to cause execution to continue at the spot marked by the \(\hookrightarrow\) key. It appears these loops can actually be nested. (Lacking a manual, I don't know how if there are any limitations concerning this behavior.)

The calculator has storage for 256 program steps, divided among four program areas. However, it seems that a single program cannot contain more than 160 steps. Since steps are unmerged (each keystroke counts as a separate step) this amount of memory is somewhat limited. However, it is still possible to implement non-trivial algorithms, as the following, fairly accurate implementation of the Gamma function demonstrates:

f(X)=
1⇒G
\(\hookrightarrow\)X>0•N→[
    G÷X⇒G
    X+1⇒X
\(\Lsh\)]
G√2π÷X×
  (1+76.18009173÷(X+1)–86.50532033÷(X+2)+
   24.01409824÷(X+3)–1.23173957÷(X+4)+
   1.20865E-3÷(X+5)–5.4E-6÷(X+6))
  (X+5.5)Yx(X+.5)×ex-(X+5.5)