Like its predecessor the HP-65, the HP-67 is another classic Hewlett-Packard calculator. (After all, they call these the classic series for a reason!) The HP-67 is functionally equivalent to the HP-97desktop printing calculator; programs are interchangeable between the two.

With 224 fully merged program steps and 26 memories, this pocket calculator is a true powerhouse. Few are the problems and far between, that cannot be easily solved by this machine. Using the HP-97 and its printer for software development made the programmer's job even easier.

The HP-67 is yet another example of the quality of Hewlett-Packard engineering. Back when it was introduced, it may have been functionally somewhat inferior to its rival from Texas Instruments, the TI-59(the latter having more memory and removeable solid state software library modules) but HP's superior workmanship clearly makes a difference when I am repairing 20-some year old calculators today.

I have recently received my first HP-67. As expected, its magnetic card reader was non-functional; the rubber transport wheel has deteriorated. (Interestingly, it did not disintegrate, it hardened instead.) However, replacing the wheel proved to be a breeze and the calculator is fully functional again. Even the old batteries still hold a charge!

The listing below is my implementation of the Gamma function for the HP-67. The program is identical to the HP-97 version; it is relisted here using HP-67 keyboard codes. To use, load the program, enter the argument, and hit the Abutton.

001  31 25 11	LBL A
002  01		1
003  35 52	x-y
004  31 25 02	LBL 2
005  31 81	x>0?
006  22 01	GTO 1
007  41		ENTER
008  35 53	Rv
009  71		×
010  35 54	R^
011  01		1
012  61		+
013  22 02	GTO 2
014  31 25 01	LBL 1
015  33 15	STO E
016  35 52	x-y
017  33 14	STO D
018  07		7
019  06		6
020  83		.
021  01		1
022  08		8
023  00		0
024  00		0
025  09		9
026  01		1
027  07		7
028  03		3
029  34 15	RCL E
030  01		1
031  61		+
032  81		÷
033  08		8
034  06		6
035  83		.
036  05		5
037  00		0
038  05		5
039  03		3
040  02		2
041  00		0
042  03		3
043  03		3
044  34 15	RCL E
045  02		2
046  61		+
047  81		÷
048  51		-
049  02		2
050  04		4
051  83		.
052  00		0
053  01		1
054  04		4
055  00		0
056  09		9
057  08		8
058  02		2
059  04		4
060  34 15	RCL E
061  03		3
062  61		+
063  81		÷
064  61		+
065  01		1
066  83		.
067  02		2
068  03		3
069  01		1
070  07		7
071  03		3
072  09		9
073  05		5
074  07		7
075  02		2
076  34 15	RCL E
077  04		4
078  61		+
079  81		÷
080  51		-
081  01		1
082  83		.
083  02		2
084  00		0
085  08		8
086  06		6
087  05		5
088  00		0
089  09		9
090  07		7
091  04		4
092  43		EEX
093  03		3
094  42		CHS
095  34 15	RCL E
096  05		5
097  61		+
098  81		÷
099  61		+
100  05		5
101  83		.
102  03		3
103  09		9
104  05		5
105  02		2
106  03		3
107  09		9
108  03		3
109  08		8
110  05		5
111  43		EEX
112  06		6
113  42		CHS
114  34 15	RCL E
115  06		6
116  61		+
117  81		÷
118  51		-
119  01		1
120  61		+
121  35 73	π
122  02		2
123  71		×
124  31 54	√
125  71		×
126  34 15	RCL E
127  81		÷
128  31 52	LN
129  34 15	RCL E
130  05		5
131  83		.
132  05		5
133  61		+
134  31 52	LN
135  34 15	RCL E
136  83		.
137  05		5
138  61		+
139  71		×
140  61		+
141  34 15	RCL E
142  51		-
143  05		5
144  83		.
145  05		5
146  51		-
147  32 52	ex
148  34 14	RCL D
149  81		÷
150  35 22	RTN