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Diffstat (limited to 'apps/plugins/frotz/variable.c')
-rw-r--r-- | apps/plugins/frotz/variable.c | 304 |
1 files changed, 304 insertions, 0 deletions
diff --git a/apps/plugins/frotz/variable.c b/apps/plugins/frotz/variable.c new file mode 100644 index 0000000000..3e5c6e0c09 --- /dev/null +++ b/apps/plugins/frotz/variable.c | |||
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1 | /* variable.c - Variable and stack related opcodes | ||
2 | * Copyright (c) 1995-1997 Stefan Jokisch | ||
3 | * | ||
4 | * This file is part of Frotz. | ||
5 | * | ||
6 | * Frotz is free software; you can redistribute it and/or modify | ||
7 | * it under the terms of the GNU General Public License as published by | ||
8 | * the Free Software Foundation; either version 2 of the License, or | ||
9 | * (at your option) any later version. | ||
10 | * | ||
11 | * Frotz is distributed in the hope that it will be useful, | ||
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
14 | * GNU General Public License for more details. | ||
15 | * | ||
16 | * You should have received a copy of the GNU General Public License | ||
17 | * along with this program; if not, write to the Free Software | ||
18 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA | ||
19 | */ | ||
20 | |||
21 | #include "frotz.h" | ||
22 | |||
23 | /* | ||
24 | * z_dec, decrement a variable. | ||
25 | * | ||
26 | * zargs[0] = variable to decrement | ||
27 | * | ||
28 | */ | ||
29 | |||
30 | void z_dec (void) | ||
31 | { | ||
32 | zword value; | ||
33 | |||
34 | if (zargs[0] == 0) | ||
35 | (*sp)--; | ||
36 | else if (zargs[0] < 16) | ||
37 | (*(fp - zargs[0]))--; | ||
38 | else { | ||
39 | zword addr = h_globals + 2 * (zargs[0] - 16); | ||
40 | LOW_WORD (addr, value) | ||
41 | value--; | ||
42 | SET_WORD (addr, value) | ||
43 | } | ||
44 | |||
45 | }/* z_dec */ | ||
46 | |||
47 | /* | ||
48 | * z_dec_chk, decrement a variable and branch if now less than value. | ||
49 | * | ||
50 | * zargs[0] = variable to decrement | ||
51 | * zargs[1] = value to check variable against | ||
52 | * | ||
53 | */ | ||
54 | |||
55 | void z_dec_chk (void) | ||
56 | { | ||
57 | zword value; | ||
58 | |||
59 | if (zargs[0] == 0) | ||
60 | value = --(*sp); | ||
61 | else if (zargs[0] < 16) | ||
62 | value = --(*(fp - zargs[0])); | ||
63 | else { | ||
64 | zword addr = h_globals + 2 * (zargs[0] - 16); | ||
65 | LOW_WORD (addr, value) | ||
66 | value--; | ||
67 | SET_WORD (addr, value) | ||
68 | } | ||
69 | |||
70 | branch ((short) value < (short) zargs[1]); | ||
71 | |||
72 | }/* z_dec_chk */ | ||
73 | |||
74 | /* | ||
75 | * z_inc, increment a variable. | ||
76 | * | ||
77 | * zargs[0] = variable to increment | ||
78 | * | ||
79 | */ | ||
80 | |||
81 | void z_inc (void) | ||
82 | { | ||
83 | zword value; | ||
84 | |||
85 | if (zargs[0] == 0) | ||
86 | (*sp)++; | ||
87 | else if (zargs[0] < 16) | ||
88 | (*(fp - zargs[0]))++; | ||
89 | else { | ||
90 | zword addr = h_globals + 2 * (zargs[0] - 16); | ||
91 | LOW_WORD (addr, value) | ||
92 | value++; | ||
93 | SET_WORD (addr, value) | ||
94 | } | ||
95 | |||
96 | }/* z_inc */ | ||
97 | |||
98 | /* | ||
99 | * z_inc_chk, increment a variable and branch if now greater than value. | ||
100 | * | ||
101 | * zargs[0] = variable to increment | ||
102 | * zargs[1] = value to check variable against | ||
103 | * | ||
104 | */ | ||
105 | |||
106 | void z_inc_chk (void) | ||
107 | { | ||
108 | zword value; | ||
109 | |||
110 | if (zargs[0] == 0) | ||
111 | value = ++(*sp); | ||
112 | else if (zargs[0] < 16) | ||
113 | value = ++(*(fp - zargs[0])); | ||
114 | else { | ||
115 | zword addr = h_globals + 2 * (zargs[0] - 16); | ||
116 | LOW_WORD (addr, value) | ||
117 | value++; | ||
118 | SET_WORD (addr, value) | ||
119 | } | ||
120 | |||
121 | branch ((short) value > (short) zargs[1]); | ||
122 | |||
123 | }/* z_inc_chk */ | ||
124 | |||
125 | /* | ||
126 | * z_load, store the value of a variable. | ||
127 | * | ||
128 | * zargs[0] = variable to store | ||
129 | * | ||
130 | */ | ||
131 | |||
132 | void z_load (void) | ||
133 | { | ||
134 | zword value; | ||
135 | |||
136 | if (zargs[0] == 0) | ||
137 | value = *sp; | ||
138 | else if (zargs[0] < 16) | ||
139 | value = *(fp - zargs[0]); | ||
140 | else { | ||
141 | zword addr = h_globals + 2 * (zargs[0] - 16); | ||
142 | LOW_WORD (addr, value) | ||
143 | } | ||
144 | |||
145 | store (value); | ||
146 | |||
147 | }/* z_load */ | ||
148 | |||
149 | /* | ||
150 | * z_pop, pop a value off the game stack and discard it. | ||
151 | * | ||
152 | * no zargs used | ||
153 | * | ||
154 | */ | ||
155 | |||
156 | void z_pop (void) | ||
157 | { | ||
158 | |||
159 | sp++; | ||
160 | |||
161 | }/* z_pop */ | ||
162 | |||
163 | /* | ||
164 | * z_pop_stack, pop n values off the game or user stack and discard them. | ||
165 | * | ||
166 | * zargs[0] = number of values to discard | ||
167 | * zargs[1] = address of user stack (optional) | ||
168 | * | ||
169 | */ | ||
170 | |||
171 | void z_pop_stack (void) | ||
172 | { | ||
173 | |||
174 | if (zargc == 2) { /* it's a user stack */ | ||
175 | |||
176 | zword size; | ||
177 | zword addr = zargs[1]; | ||
178 | |||
179 | LOW_WORD (addr, size) | ||
180 | |||
181 | size += zargs[0]; | ||
182 | storew (addr, size); | ||
183 | |||
184 | } else sp += zargs[0]; /* it's the game stack */ | ||
185 | |||
186 | }/* z_pop_stack */ | ||
187 | |||
188 | /* | ||
189 | * z_pull, pop a value off... | ||
190 | * | ||
191 | * a) ...the game or a user stack and store it (V6) | ||
192 | * | ||
193 | * zargs[0] = address of user stack (optional) | ||
194 | * | ||
195 | * b) ...the game stack and write it to a variable (other than V6) | ||
196 | * | ||
197 | * zargs[0] = variable to write value to | ||
198 | * | ||
199 | */ | ||
200 | |||
201 | void z_pull (void) | ||
202 | { | ||
203 | zword value; | ||
204 | |||
205 | if (h_version != V6) { /* not a V6 game, pop stack and write */ | ||
206 | |||
207 | value = *sp++; | ||
208 | |||
209 | if (zargs[0] == 0) | ||
210 | *sp = value; | ||
211 | else if (zargs[0] < 16) | ||
212 | *(fp - zargs[0]) = value; | ||
213 | else { | ||
214 | zword addr = h_globals + 2 * (zargs[0] - 16); | ||
215 | SET_WORD (addr, value) | ||
216 | } | ||
217 | |||
218 | } else { /* it's V6, but is there a user stack? */ | ||
219 | |||
220 | if (zargc == 1) { /* it's a user stack */ | ||
221 | |||
222 | zword size; | ||
223 | zword addr = zargs[0]; | ||
224 | |||
225 | LOW_WORD (addr, size) | ||
226 | |||
227 | size++; | ||
228 | storew (addr, size); | ||
229 | |||
230 | addr += 2 * size; | ||
231 | LOW_WORD (addr, value) | ||
232 | |||
233 | } else value = *sp++; /* it's the game stack */ | ||
234 | |||
235 | store (value); | ||
236 | |||
237 | } | ||
238 | |||
239 | }/* z_pull */ | ||
240 | |||
241 | /* | ||
242 | * z_push, push a value onto the game stack. | ||
243 | * | ||
244 | * zargs[0] = value to push onto the stack | ||
245 | * | ||
246 | */ | ||
247 | |||
248 | void z_push (void) | ||
249 | { | ||
250 | |||
251 | *--sp = zargs[0]; | ||
252 | |||
253 | }/* z_push */ | ||
254 | |||
255 | /* | ||
256 | * z_push_stack, push a value onto a user stack then branch if successful. | ||
257 | * | ||
258 | * zargs[0] = value to push onto the stack | ||
259 | * zargs[1] = address of user stack | ||
260 | * | ||
261 | */ | ||
262 | |||
263 | void z_push_stack (void) | ||
264 | { | ||
265 | zword size; | ||
266 | zword addr = zargs[1]; | ||
267 | |||
268 | LOW_WORD (addr, size) | ||
269 | |||
270 | if (size != 0) { | ||
271 | |||
272 | storew ((zword) (addr + 2 * size), zargs[0]); | ||
273 | |||
274 | size--; | ||
275 | storew (addr, size); | ||
276 | |||
277 | } | ||
278 | |||
279 | branch (size); | ||
280 | |||
281 | }/* z_push_stack */ | ||
282 | |||
283 | /* | ||
284 | * z_store, write a value to a variable. | ||
285 | * | ||
286 | * zargs[0] = variable to be written to | ||
287 | * zargs[1] = value to write | ||
288 | * | ||
289 | */ | ||
290 | |||
291 | void z_store (void) | ||
292 | { | ||
293 | zword value = zargs[1]; | ||
294 | |||
295 | if (zargs[0] == 0) | ||
296 | *sp = value; | ||
297 | else if (zargs[0] < 16) | ||
298 | *(fp - zargs[0]) = value; | ||
299 | else { | ||
300 | zword addr = h_globals + 2 * (zargs[0] - 16); | ||
301 | SET_WORD (addr, value) | ||
302 | } | ||
303 | |||
304 | }/* z_store */ | ||