The TI-58 calculator is the smaller cousin of Texas Instrument's legendary TI-59. The TI-58 had half the memory and no card reader, which meant that programs were lost when the calculator was powered down, thereby substantially reducing its utility. The TI-58C was a TI-58 with continuous memory (i.e., memory that retains its contents even when the calculator turned off.) Continuous memory greatly alleviated one of the design shortcomings of this model: in order to hook up the machine to the optional PC-100 printer/security cradle, it was necessary to turn it off, which meant losing the contents of program memory/data registers. This was no longer the case with the TI-58C as memory contents were preserved.

I now own several working TI-58Cs, one of them a result of some transplant surgery, as I combined a keyboard from one calculator (with dysfunctional memory, possibly a result of attempts to operate the calculator from a charger, but with no battery inside) with the rest of the innards from another. As I was doing this, I couldn't help but notice the relatively shoddy construction of these calculators compared to a 1977 TI-59.

While it is possible to use on this calculator the complex Gamma function program I wrote for the TI-59 (use 2 Op 17to set a suitable memory configuration), a smaller, real-only implementation is more appropriate for this calculator's more limited memory. Another advantage of this version is speed  and the fact that this program doesn't require a solid state library module. (Of course, you can also use this program on the TI-59, where it fits onto one side of a magnetic card, making it not only faster but more convenient to use.)

To calculate the Gamma function of a real argument after this program has been keyed in, enter the argument and hit the Abutton.

000 76	LBL
001 11	A
002 32	x-t
003 01	1
004 42	STO
005 00	00
006 76	LBL
007 32	x-t
008 00	0
009 32	x-t
010 77	x>=t
011 61	GTO
012 49	PRD
013 00	00
014 85	+
015 01	1
016 95	=
017 32	x-t
018 61	GTO
019 32	x-t
020 76	LBL
021 61	GTO
022 42	STO
023 01	01
024 93	.
025 01	1
026 08	8
027 00	0
028 00	0
029 09	9
030 01	1
031 07	7
032 02	2
033 09	9
034 04	4
035 85	+
036 07	7
037 06	6
038 95	=
039 55	÷
040 53	(
041 43	RCL
042 01	01
043 85	+
044 01	1
045 54	)
046 75	-
047 53	(
048 93	.
049 05	5
050 00	0
051 05	5
052 03	3
053 02	2
054 00	0
055 03	3
056 02	2
057 09	9
058 04	4
059 85	+
060 08	8
061 06	6
062 54	)
063 55	÷
064 53	(
065 43	RCL
066 01	01
067 85	+
068 02	2
069 54	)
070 85	+
071 53	(
072 93	.
073 00	0
074 01	1
075 04	4
076 00	0
077 09	9
078 08	8
079 02	2
080 04	4
081 08	8
082 03	3
083 85	+
084 02	2
085 04	4
086 54	)
087 55	÷
088 53	(
089 43	RCL
090 01	01
091 85	+
092 03	3
093 54	)
094 75	-
095 53	(
096 93	.
097 02	2
098 03	3
099 01	1
100 07	7
101 03	3
102 09	9
103 05	5
104 07	7
105 02	2
106 05	5
107 85	+
108 01	1
109 54	)
110 55	÷
111 53	(
112 43	RCL
113 01	01
114 85	+
115 04	4
116 54	)
117 85	+
118 53	(
119 93	.
120 02	2
121 00	0
122 08	8
123 06	6
124 05	5
125 00	0
126 09	9
127 07	7
128 03	3
129 09	9
130 85	+
131 01	1
132 54	)
133 55	÷
134 01	1
135 00	0
136 00	0
137 00	0
138 55	÷
139 53	(
140 43	RCL
141 01	01
142 85	+
143 05	5
144 54	)
145 75	-
146 53	(
147 93	.
148 03	3
149 09	9
150 05	5
151 02	2
152 03	3
153 09	9
154 03	3
155 08	8
156 05	5
157 85	+
158 05	5
159 54	)
160 55	÷
161 01	1
162 00	0
163 00	0
164 00	0
165 00	0
166 00	0
167 00	0
168 55	÷
169 53	(
170 43	RCL
171 01	01
172 85	+
173 06	6
174 54	)
175 85	+
176 05	1
177 85	+
178 01	1
179 93	.
180 09	9
181 55	÷
182 01	1
183 00	0
184 00	0
185 00	0
186 00	0
187 00	0
188 33	x2
189 95	=
190 65	×
191 53	(
192 02	2
193 65	×
194 89	π
195 54	)
196 34	√
197 55	÷
198 43	RCL
199 01	01
200 95	=
201 23	lnx
202 85	+
203 53	(
204 43	RCL
205 01	01
206 85	+
207 05	5
208 93	.
209 05	5
210 54	)
211 23	lnx
212 65	×
213 53	(
214 43	RCL
215 01	01
216 85	+
217 93	.
218 05	5
219 54	)
220 75	-
221 43	RCL
222 01	01
223 75	-
224 05	5
225 93	.
226 05	5
227 95	=
228 22	INV
229 23	lnx
230 55	÷
231 43	RCL
232 00	00
233 95	=
234 92	RTN