2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
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26 * $FreeBSD: src/sys/boot/common/interp_forth.c,v 1.15.2.2 2000/12/28 13:12:34 ps Exp $
29 #include <sys/param.h> /* to pick up __FreeBSD_version */
32 #include "bootstrap.h"
35 extern char bootprog_rev[];
37 /* #define BFORTH_DEBUG */
40 # define DEBUG(fmt, args...) printf("%s: " fmt "\n" , __FUNCTION__ , ## args)
42 # define DEBUG(fmt, args...)
46 * Eventually, all builtin commands throw codes must be defined
47 * elsewhere, possibly bootstrap.h. For now, just this code, used
48 * just in this file, it is getting defined.
53 * BootForth Interface to Ficl Forth interpreter.
60 * Shim for taking commands from BF and passing them out to 'standard'
61 * argv/argc command functions.
64 bf_command(FICL_VM *vm)
66 char *name, *line, *tail, *cp;
68 struct bootblk_command **cmdp;
74 /* Get the name of the current word */
75 name = vm->runningWord->name;
77 /* Find our command structure */
79 SET_FOREACH(cmdp, Xcommand_set) {
80 if (((*cmdp)->c_name != NULL) && !strcmp(name, (*cmdp)->c_name))
84 panic("callout for unknown command '%s'", name);
86 /* Check whether we have been compiled or are being interpreted */
87 if (stackPopINT(vm->pStack)) {
89 * Get parameters from stack, in the format:
90 * an un ... a2 u2 a1 u1 n --
91 * Where n is the number of strings, a/u are pairs of
92 * address/size for strings, and they will be concatenated
95 nstrings = stackPopINT(vm->pStack);
96 for (i = 0, len = 0; i < nstrings; i++)
97 len += stackFetch(vm->pStack, i * 2).i + 1;
98 line = malloc(strlen(name) + len + 1);
102 for (i = 0; i < nstrings; i++) {
103 len = stackPopINT(vm->pStack);
104 cp = stackPopPtr(vm->pStack);
106 strncat(line, cp, len);
109 /* Get remainder of invocation */
110 tail = vmGetInBuf(vm);
111 for (cp = tail, len = 0; cp != vm->tib.end && *cp != 0 && *cp != '\n'; cp++, len++)
114 line = malloc(strlen(name) + len + 2);
118 strncat(line, tail, len);
119 vmUpdateTib(vm, tail + len);
122 DEBUG("cmd '%s'", line);
124 command_errmsg = command_errbuf;
125 command_errbuf[0] = 0;
126 if (!parse(&argc, &argv, line)) {
127 result = (cmd)(argc, argv);
133 /* This is going to be thrown!!! */
134 stackPushINT(vm->pStack,result);
138 * Replace a word definition (a builtin command) with another
141 * - Throw error results instead of returning them on the stack
142 * - Pass a flag indicating whether the word was compiled or is
145 * There is one major problem with builtins that cannot be overcome
146 * in anyway, except by outlawing it. We want builtins to behave
147 * differently depending on whether they have been compiled or they
148 * are being interpreted. Notice that this is *not* the interpreter's
149 * current state. For example:
151 * : example ls ; immediate
152 * : problem example ; \ "ls" gets executed while compiling
153 * example \ "ls" gets executed while interpreting
155 * Notice that, though the current state is different in the two
156 * invocations of "example", in both cases "ls" has been
157 * *compiled in*, which is what we really want.
159 * The problem arises when you tick the builtin. For example:
161 * : example-1 ['] ls postpone literal ; immediate
162 * : example-2 example-1 execute ; immediate
163 * : problem example-2 ;
166 * We have no way, when we get EXECUTEd, of knowing what our behavior
167 * should be. Thus, our only alternative is to "outlaw" this. See RFI
168 * 0007, and ANS Forth Standard's appendix D, item 6.7 for a related
169 * problem, concerning compile semantics.
171 * The problem is compounded by the fact that "' builtin CATCH" is valid
172 * and desirable. The only solution is to create an intermediary word.
176 * : example ['] my-ls catch ;
178 * So, with the below implementation, here is a summary of the behavior
181 * ls -l \ "interpret" behavior, ie,
182 * \ takes parameters from TIB
183 * : ex-1 s" -l" 1 ls ; \ "compile" behavior, ie,
184 * \ takes parameters from the stack
185 * : ex-2 ['] ls catch ; immediate \ undefined behavior
186 * : ex-3 ['] ls catch ; \ undefined behavior
187 * ex-2 ex-3 \ "interpret" behavior,
189 * : ex-4 ex-2 ; \ "compile" behavior,
190 * \ catch does not work
191 * : ex-5 ex-3 ; immediate \ same as ex-2
192 * : ex-6 ex-3 ; \ same as ex-3
193 * : ex-7 ['] ex-1 catch ; \ "compile" behavior,
195 * : ex-8 postpone ls ; immediate \ same as ex-2
196 * : ex-9 postpone ls ; \ same as ex-3
198 * As the definition below is particularly tricky, and it's side effects
199 * must be well understood by those playing with it, I'll be heavy on
202 * (if you edit this definition, pay attention to trailing spaces after
203 * each word -- I warned you! :-) )
205 #define BUILTIN_CONSTRUCTOR \
207 ">in @ " /* save the tib index pointer */ \
208 "' " /* get next word's xt */ \
209 "swap >in ! " /* point again to next word */ \
210 "create " /* create a new definition of the next word */ \
211 ", " /* save previous definition's xt */ \
212 "immediate " /* make the new definition an immediate word */ \
214 "does> " /* Now, the *new* definition will: */ \
215 "state @ if " /* if in compiling state: */ \
216 "1 postpone literal " /* pass 1 flag to indicate compile */ \
217 "@ compile, " /* compile in previous definition */ \
218 "postpone throw " /* throw stack-returned result */ \
219 "else " /* if in interpreting state: */ \
220 "0 swap " /* pass 0 flag to indicate interpret */ \
221 "@ execute " /* call previous definition */ \
222 "throw " /* throw stack-returned result */ \
226 * Initialise the Forth interpreter, create all our commands as words.
231 struct bootblk_command **cmdp;
232 char create_buf[41]; /* 31 characters-long builtins */
235 ficlInitSystem(10000); /* Default dictionary ~4000 cells */
238 /* Put all private definitions in a "builtins" vocabulary */
239 ficlExec(bf_vm, "vocabulary builtins also builtins definitions");
241 /* Builtin constructor word */
242 ficlExec(bf_vm, BUILTIN_CONSTRUCTOR);
244 /* make all commands appear as Forth words */
245 SET_FOREACH(cmdp, Xcommand_set) {
246 ficlBuild((*cmdp)->c_name, bf_command, FW_DEFAULT);
247 ficlExec(bf_vm, "forth definitions builtins");
248 sprintf(create_buf, "builtin: %s", (*cmdp)->c_name);
249 ficlExec(bf_vm, create_buf);
250 ficlExec(bf_vm, "builtins definitions");
252 ficlExec(bf_vm, "only forth definitions");
254 /* Export some version numbers so that code can detect the loader/host version */
255 ficlSetEnv("FreeBSD_version", __FreeBSD_version);
256 ficlSetEnv("loader_version",
257 (bootprog_rev[0] - '0') * 10 + (bootprog_rev[2] - '0'));
259 /* try to load and run init file if present */
260 if ((fd = open("/boot/boot.4th", O_RDONLY)) != -1) {
261 (void)ficlExecFD(bf_vm, fd);
265 /* Do this last, so /boot/boot.4th can change it */
266 pInterp = ficlLookup("interpret");
270 * Feed a line of user input to the Forth interpreter
277 result = ficlExec(bf_vm, line);
279 DEBUG("ficlExec '%s' = %d", line, result);
287 printf("No where to leave to!\n");
290 printf("Aborted!\n");
293 printf("Parse error!\n");
296 /* Hopefully, all other codes filled this buffer */
297 printf("%s\n", command_errmsg);
300 if (result == VM_USEREXIT)
301 panic("interpreter exit");
302 setenv("interpret", bf_vm->state ? "" : "ok", 1);