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100
101 <div class="header">
102 <div class="summary">
103 <a href="#define-members">Macros</a> |
104 <a href="#func-members">Functions</a> |
105 <a href="#var-members">Variables</a> </div>
106 <div class="headertitle"><div class="title">rand.h File Reference</div></div>
107 </div><!--header-->
108 <div class="contents">
109 <div class="textblock"><code>#include <<a class="el" href="types_8h_source.html">types.h</a>></code><br />
110 <code>#include <<a class="el" href="stdint_8h_source.html">stdint.h</a>></code><br />
111 </div>
112 <p><a href="rand_8h_source.html">Go to the source code of this file.</a></p>
113 <table class="memberdecls">
114 <tr class="heading"><td colspan="2"><h2 class="groupheader"><a id="define-members" name="define-members"></a>
115 Macros</h2></td></tr>
116 <tr class="memitem:RAND_MAX"><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="rand_8h.html#RAND_MAX">RAND_MAX</a>   255</td></tr>
117 <tr class="separator:RAND_MAX"><td class="memSeparator" colspan="2"> </td></tr>
118 <tr class="memitem:RANDW_MAX"><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="rand_8h.html#RANDW_MAX">RANDW_MAX</a>   65535</td></tr>
119 <tr class="separator:RANDW_MAX"><td class="memSeparator" colspan="2"> </td></tr>
120 </table><table class="memberdecls">
121 <tr class="heading"><td colspan="2"><h2 class="groupheader"><a id="func-members" name="func-members"></a>
122 Functions</h2></td></tr>
123 <tr class="memitem:initrand"><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="rand_8h.html#initrand">initrand</a> (<a class="el" href="stdint_8h.html#uint16_t">uint16_t</a> seed) <a class="el" href="asm_2types_8h.html#OLDCALL">OLDCALL</a></td></tr>
124 <tr class="separator:initrand"><td class="memSeparator" colspan="2"> </td></tr>
125 <tr class="memitem:rand"><td class="memItemLeft" align="right" valign="top"><a class="el" href="stdint_8h.html#uint8_t">uint8_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="rand_8h.html#rand">rand</a> (void) <a class="el" href="asm_2types_8h.html#OLDCALL">OLDCALL</a> <a class="el" href="asm_2types_8h.html#PRESERVES_REGS">PRESERVES_REGS</a>(<a class="el" href="sms_8h.html#b">b</a></td></tr>
126 <tr class="separator:rand"><td class="memSeparator" colspan="2"> </td></tr>
127 <tr class="memitem:randw"><td class="memItemLeft" align="right" valign="top"><a class="el" href="stdint_8h.html#uint16_t">uint16_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="rand_8h.html#randw">randw</a> (void) <a class="el" href="asm_2types_8h.html#OLDCALL">OLDCALL</a> <a class="el" href="asm_2types_8h.html#PRESERVES_REGS">PRESERVES_REGS</a>(<a class="el" href="sms_8h.html#b">b</a></td></tr>
128 <tr class="separator:randw"><td class="memSeparator" colspan="2"> </td></tr>
129 <tr class="memitem:initarand"><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="rand_8h.html#initarand">initarand</a> (<a class="el" href="stdint_8h.html#uint16_t">uint16_t</a> seed) <a class="el" href="asm_2types_8h.html#OLDCALL">OLDCALL</a></td></tr>
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132 <tr class="separator:arand"><td class="memSeparator" colspan="2"> </td></tr>
133 </table><table class="memberdecls">
134 <tr class="heading"><td colspan="2"><h2 class="groupheader"><a id="var-members" name="var-members"></a>
135 Variables</h2></td></tr>
136 <tr class="memitem:__rand_seed"><td class="memItemLeft" align="right" valign="top"><a class="el" href="stdint_8h.html#uint16_t">uint16_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="rand_8h.html#__rand_seed">__rand_seed</a></td></tr>
137 <tr class="separator:__rand_seed"><td class="memSeparator" colspan="2"> </td></tr>
138 <tr class="memitem:c"><td class="memItemLeft" align="right" valign="top"><a class="el" href="stdint_8h.html#uint8_t">uint8_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="rand_8h.html#c">c</a></td></tr>
139 <tr class="separator:c"><td class="memSeparator" colspan="2"> </td></tr>
140 </table>
141 <a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
142 <div class="textblock"><p >Random generator using the linear congruential method</p>
143 <dl class="section author"><dt>Author</dt><dd>Luc Van den Borre </dd></dl>
144 </div><h2 class="groupheader">Macro Definition Documentation</h2>
145 <a id="RAND_MAX" name="RAND_MAX"></a>
146 <h2 class="memtitle"><span class="permalink"><a href="#RAND_MAX">◆ </a></span>RAND_MAX</h2>
147
148 <div class="memitem">
149 <div class="memproto">
150 <table class="memname">
151 <tr>
152 <td class="memname">#define RAND_MAX   255</td>
153 </tr>
154 </table>
155 </div><div class="memdoc">
156
157 </div>
158 </div>
159 <a id="RANDW_MAX" name="RANDW_MAX"></a>
160 <h2 class="memtitle"><span class="permalink"><a href="#RANDW_MAX">◆ </a></span>RANDW_MAX</h2>
161
162 <div class="memitem">
163 <div class="memproto">
164 <table class="memname">
165 <tr>
166 <td class="memname">#define RANDW_MAX   65535</td>
167 </tr>
168 </table>
169 </div><div class="memdoc">
170
171 </div>
172 </div>
173 <h2 class="groupheader">Function Documentation</h2>
174 <a id="initrand" name="initrand"></a>
175 <h2 class="memtitle"><span class="permalink"><a href="#initrand">◆ </a></span>initrand()</h2>
176
177 <div class="memitem">
178 <div class="memproto">
179 <table class="memname">
180 <tr>
181 <td class="memname">void initrand </td>
182 <td>(</td>
183 <td class="paramtype"><a class="el" href="stdint_8h.html#uint16_t">uint16_t</a> </td>
184 <td class="paramname"><em>seed</em></td><td>)</td>
185 <td></td>
186 </tr>
187 </table>
188 </div><div class="memdoc">
189 <p >Initalise the pseudo-random number generator.</p>
190 <dl class="params"><dt>Parameters</dt><dd>
191 <table class="params">
192 <tr><td class="paramname">seed</td><td>The value for initializing the random number generator.</td></tr>
193 </table>
194 </dd>
195 </dl>
196 <p>The seed should be different each time, otherwise the same pseudo-random sequence will be generated.</p>
197 <p >One way to do this is sampling (<a class="el" href="gb_2hardware_8h.html#DIV_REG">DIV_REG</a>) up to 2 times (high byte of seed value then the low byte) at variable, non-deterministic points in time (such as when the player presses buttons on the title screen or in a menu).</p>
198 <p >It only needs to be called once to be initialized.</p>
199 <dl class="section see"><dt>See also</dt><dd><a class="el" href="rand_8h.html#rand">rand()</a>, <a class="el" href="rand_8h.html#randw">randw()</a> </dd></dl>
200
201 </div>
202 </div>
203 <a id="rand" name="rand"></a>
204 <h2 class="memtitle"><span class="permalink"><a href="#rand">◆ </a></span>rand()</h2>
205
206 <div class="memitem">
207 <div class="memproto">
208 <table class="memname">
209 <tr>
210 <td class="memname"><a class="el" href="stdint_8h.html#uint8_t">uint8_t</a> rand </td>
211 <td>(</td>
212 <td class="paramtype">void </td>
213 <td class="paramname"></td><td>)</td>
214 <td></td>
215 </tr>
216 </table>
217 </div><div class="memdoc">
218 <p >Returns a random byte (8 bit) value.</p>
219 <p ><a class="el" href="rand_8h.html#initrand">initrand()</a> should be used to initialize the random number generator before using <a class="el" href="rand_8h.html#rand">rand()</a> </p>
220
221 </div>
222 </div>
223 <a id="randw" name="randw"></a>
224 <h2 class="memtitle"><span class="permalink"><a href="#randw">◆ </a></span>randw()</h2>
225
226 <div class="memitem">
227 <div class="memproto">
228 <table class="memname">
229 <tr>
230 <td class="memname"><a class="el" href="stdint_8h.html#uint16_t">uint16_t</a> randw </td>
231 <td>(</td>
232 <td class="paramtype">void </td>
233 <td class="paramname"></td><td>)</td>
234 <td></td>
235 </tr>
236 </table>
237 </div><div class="memdoc">
238 <p >Returns a random word (16 bit) value.</p>
239 <p ><a class="el" href="rand_8h.html#initrand">initrand()</a> should be used to initialize the random number generator before using <a class="el" href="rand_8h.html#rand">rand()</a> </p>
240
241 </div>
242 </div>
243 <a id="initarand" name="initarand"></a>
244 <h2 class="memtitle"><span class="permalink"><a href="#initarand">◆ </a></span>initarand()</h2>
245
246 <div class="memitem">
247 <div class="memproto">
248 <table class="memname">
249 <tr>
250 <td class="memname">void initarand </td>
251 <td>(</td>
252 <td class="paramtype"><a class="el" href="stdint_8h.html#uint16_t">uint16_t</a> </td>
253 <td class="paramname"><em>seed</em></td><td>)</td>
254 <td></td>
255 </tr>
256 </table>
257 </div><div class="memdoc">
258 <p >Random generator using the linear lagged additive method</p>
259 <dl class="params"><dt>Parameters</dt><dd>
260 <table class="params">
261 <tr><td class="paramname">seed</td><td>The value for initializing the random number generator.</td></tr>
262 </table>
263 </dd>
264 </dl>
265 <p>Note: <a class="el" href="rand_8h.html#initarand">initarand()</a> calls <a class="el" href="rand_8h.html#initrand">initrand()</a> with the same seed value, and uses <a class="el" href="rand_8h.html#rand">rand()</a> to initialize the random generator.</p>
266 <dl class="section see"><dt>See also</dt><dd><a class="el" href="rand_8h.html#initrand">initrand()</a> for suggestions about seed values, <a class="el" href="rand_8h.html#arand">arand()</a> </dd></dl>
267
268 </div>
269 </div>
270 <a id="arand" name="arand"></a>
271 <h2 class="memtitle"><span class="permalink"><a href="#arand">◆ </a></span>arand()</h2>
272
273 <div class="memitem">
274 <div class="memproto">
275 <table class="memname">
276 <tr>
277 <td class="memname"><a class="el" href="stdint_8h.html#uint8_t">uint8_t</a> arand </td>
278 <td>(</td>
279 <td class="paramtype">void </td>
280 <td class="paramname"></td><td>)</td>
281 <td></td>
282 </tr>
283 </table>
284 </div><div class="memdoc">
285 <p >Returns a random number generated with the linear lagged additive method.</p>
286 <p ><a class="el" href="rand_8h.html#initarand">initarand()</a> should be used to initialize the random number generator before using <a class="el" href="rand_8h.html#arand">arand()</a> </p>
287
288 </div>
289 </div>
290 <h2 class="groupheader">Variable Documentation</h2>
291 <a id="__rand_seed" name="__rand_seed"></a>
292 <h2 class="memtitle"><span class="permalink"><a href="#__rand_seed">◆ </a></span>__rand_seed</h2>
293
294 <div class="memitem">
295 <div class="memproto">
296 <table class="mlabels">
297 <tr>
298 <td class="mlabels-left">
299 <table class="memname">
300 <tr>
301 <td class="memname"><a class="el" href="stdint_8h.html#uint16_t">uint16_t</a> __rand_seed</td>
302 </tr>
303 </table>
304 </td>
305 <td class="mlabels-right">
306 <span class="mlabels"><span class="mlabel">extern</span></span> </td>
307 </tr>
308 </table>
309 </div><div class="memdoc">
310 <p >The random number seed is stored in __rand_seed and can be saved and restored if needed.</p>
311 <div class="fragment"><div class="line"><span class="comment">// Save</span></div>
312 <div class="line">some_uint16 = <a class="code hl_variable" href="rand_8h.html#__rand_seed">__rand_seed</a>;</div>
313 <div class="line">...</div>
314 <div class="line"><span class="comment">// Restore</span></div>
315 <div class="line">__rand_seed = some_uint16;</div>
316 <div class="ttc" id="arand_8h_html___rand_seed"><div class="ttname"><a href="rand_8h.html#__rand_seed">__rand_seed</a></div><div class="ttdeci">uint16_t __rand_seed</div></div>
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