The HP-38C/E was the high-end financial calculator of the HP 30-series. The C model had Continuous Memory; contents of the calculator's memory were not erased when the calculator was switched o-ff.

High-end, as it was usual with Hewlett-Packard calculators at the time, meant programming: the HP-38C/E provided room for a maximum of 99 program steps. A testament to its versatility, and to the power of merged keystroke programming, is the fact that this amount of program memory was sufficient to create a Gamma function implementation that calculated the function's value for any real argument. The program, shown below, consists of 82 merged steps; in addition, it is necessary to fill registers 0-6 with a set of predefined values. The program also makes use of registers 7 and 8.

M0:    √2π = 2.506628275
M1:    76.18009173
M2:    86.50532033
M3:    24.01409824
M4:    1.231739572
M5:    1.208650974e-3
M6:    5.395239385e-6

01 -    1        1
02 -    33       x-y
03 -    0        0
04 -    25 5     x<=y
05 -    25 7 16  GTO 16
06 -    25 33    Rv
07 -    31       ENTER
08 -    25 33    Rv
09 -    61       ×
10 -    25 33    Rv
11 -    25 33    Rv
12 -    25 33    Rv
13 -    1        1
14 -    51       +
15 -    25 7 03  GTO 03
16 -    25 33    Rv
17 -    21 7     STO 7
18 -    33       x-y
19 -    21 8     STO 8
20 -    22 1     RCL 1
21 -    22 7     RCL 7
22 -    1        1
23 -    51       +
24 -    71       ÷
25 -    22 2     RCL 2
26 -    22 7     RCL 7
27 -    2        2
28 -    51       +
29 -    71       ÷
30 -    41       -
31 -    22 3     RCL 3
32 -    22 7     RCL 7
33 -    3        3
34 -    51       +
35 -    71       ÷
36 -    51       +
37 -    22 4     RCL 4
38 -    22 7     RCL 7
39 -    4        4
40 -    51       +
41 -    71       ÷
42 -    41       -
43 -    22 5     RCL 5
44 -    22 7     RCL 7
45 -    5        5
46 -    51       +
47 -    71       ÷
48 -    51       +
49 -    22 6     RCL 6
50 -    22 7     RCL 7
51 -    6        6
52 -    51       +
53 -    71       ÷
54 -    41       -
55 -    1        1
56 -    51       +
57 -    22 0     RCL 0
58 -    61       ×
59 -    22 7     RCL 7
60 -    71       ÷
61 -    25 23    LN
62 -    22 7     RCL 7
63 -    5        5
64 -    73       .
65 -    5        5
66 -    51       +
67 -    25 23    LN
68 -    22 7     RCL 7
69 -    73       .
70 -    5        5
71 -    51       +
72 -    61       ×
73 -    51       +
74 -    22 7     RCL 7
75 -    41       -
76 -    5        5
77 -    73       .
78 -    5        5
79 -    41       -
80 -    25 22    ex
81 -    22 8     RCL 8
82 -    71       ÷