# Fibonacci using terminfo's native integer addition, traced on stdout.
#
# export TERMINFO="$PWD"; tic fib.txt; yes 'cup 0 0' | head -n 10 | TERM=fib tput -S
#
# Registers:
#   A = F(N-1)
#   B = F(N)
#   N = current Fibonacci index, step counter and initialized flag
#
#   if (N == 0) {
#       A = 0; B = 1; N = 1;                       // init
#   } else {
#       stack: B' = A + B, A' = old B; N = N + 1;  // compute next value
#   }
#   print trace line

fib,cup=
    %?%gN%{0}%=%t%{0}%PA%{1}%PB%{1}%PN
    %e%gA%gB%+%gB%PA%PB%gN%{1}%+%PN%;
    A=%gA%d B=%gB%d N=%gN%d F(%gN%d)=%gB%d\r\n,