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.
10 * 2. Redistributions in binary form must reproduce the above copyright
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21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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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 $
27 * $DragonFly: src/sys/boot/common/interp_forth.c,v 1.2 2003/06/17 04:28:16 dillon Exp $
30 #include <sys/param.h> /* to pick up __FreeBSD_version */
33 #include "bootstrap.h"
36 extern char bootprog_rev[];
38 /* #define BFORTH_DEBUG */
41 # define DEBUG(fmt, args...) printf("%s: " fmt "\n" , __FUNCTION__ , ## args)
43 # define DEBUG(fmt, args...)
47 * Eventually, all builtin commands throw codes must be defined
48 * elsewhere, possibly bootstrap.h. For now, just this code, used
49 * just in this file, it is getting defined.
54 * BootForth Interface to Ficl Forth interpreter.
61 * Shim for taking commands from BF and passing them out to 'standard'
62 * argv/argc command functions.
65 bf_command(FICL_VM *vm)
67 char *name, *line, *tail, *cp;
69 struct bootblk_command **cmdp;
75 /* Get the name of the current word */
76 name = vm->runningWord->name;
78 /* Find our command structure */
80 SET_FOREACH(cmdp, Xcommand_set) {
81 if (((*cmdp)->c_name != NULL) && !strcmp(name, (*cmdp)->c_name))
85 panic("callout for unknown command '%s'", name);
87 /* Check whether we have been compiled or are being interpreted */
88 if (stackPopINT(vm->pStack)) {
90 * Get parameters from stack, in the format:
91 * an un ... a2 u2 a1 u1 n --
92 * Where n is the number of strings, a/u are pairs of
93 * address/size for strings, and they will be concatenated
96 nstrings = stackPopINT(vm->pStack);
97 for (i = 0, len = 0; i < nstrings; i++)
98 len += stackFetch(vm->pStack, i * 2).i + 1;
99 line = malloc(strlen(name) + len + 1);
103 for (i = 0; i < nstrings; i++) {
104 len = stackPopINT(vm->pStack);
105 cp = stackPopPtr(vm->pStack);
107 strncat(line, cp, len);
110 /* Get remainder of invocation */
111 tail = vmGetInBuf(vm);
112 for (cp = tail, len = 0; cp != vm->tib.end && *cp != 0 && *cp != '\n'; cp++, len++)
115 line = malloc(strlen(name) + len + 2);
119 strncat(line, tail, len);
120 vmUpdateTib(vm, tail + len);
123 DEBUG("cmd '%s'", line);
125 command_errmsg = command_errbuf;
126 command_errbuf[0] = 0;
127 if (!parse(&argc, &argv, line)) {
128 result = (cmd)(argc, argv);
134 /* This is going to be thrown!!! */
135 stackPushINT(vm->pStack,result);
139 * Replace a word definition (a builtin command) with another
142 * - Throw error results instead of returning them on the stack
143 * - Pass a flag indicating whether the word was compiled or is
146 * There is one major problem with builtins that cannot be overcome
147 * in anyway, except by outlawing it. We want builtins to behave
148 * differently depending on whether they have been compiled or they
149 * are being interpreted. Notice that this is *not* the interpreter's
150 * current state. For example:
152 * : example ls ; immediate
153 * : problem example ; \ "ls" gets executed while compiling
154 * example \ "ls" gets executed while interpreting
156 * Notice that, though the current state is different in the two
157 * invocations of "example", in both cases "ls" has been
158 * *compiled in*, which is what we really want.
160 * The problem arises when you tick the builtin. For example:
162 * : example-1 ['] ls postpone literal ; immediate
163 * : example-2 example-1 execute ; immediate
164 * : problem example-2 ;
167 * We have no way, when we get EXECUTEd, of knowing what our behavior
168 * should be. Thus, our only alternative is to "outlaw" this. See RFI
169 * 0007, and ANS Forth Standard's appendix D, item 6.7 for a related
170 * problem, concerning compile semantics.
172 * The problem is compounded by the fact that "' builtin CATCH" is valid
173 * and desirable. The only solution is to create an intermediary word.
177 * : example ['] my-ls catch ;
179 * So, with the below implementation, here is a summary of the behavior
182 * ls -l \ "interpret" behavior, ie,
183 * \ takes parameters from TIB
184 * : ex-1 s" -l" 1 ls ; \ "compile" behavior, ie,
185 * \ takes parameters from the stack
186 * : ex-2 ['] ls catch ; immediate \ undefined behavior
187 * : ex-3 ['] ls catch ; \ undefined behavior
188 * ex-2 ex-3 \ "interpret" behavior,
190 * : ex-4 ex-2 ; \ "compile" behavior,
191 * \ catch does not work
192 * : ex-5 ex-3 ; immediate \ same as ex-2
193 * : ex-6 ex-3 ; \ same as ex-3
194 * : ex-7 ['] ex-1 catch ; \ "compile" behavior,
196 * : ex-8 postpone ls ; immediate \ same as ex-2
197 * : ex-9 postpone ls ; \ same as ex-3
199 * As the definition below is particularly tricky, and it's side effects
200 * must be well understood by those playing with it, I'll be heavy on
203 * (if you edit this definition, pay attention to trailing spaces after
204 * each word -- I warned you! :-) )
206 #define BUILTIN_CONSTRUCTOR \
208 ">in @ " /* save the tib index pointer */ \
209 "' " /* get next word's xt */ \
210 "swap >in ! " /* point again to next word */ \
211 "create " /* create a new definition of the next word */ \
212 ", " /* save previous definition's xt */ \
213 "immediate " /* make the new definition an immediate word */ \
215 "does> " /* Now, the *new* definition will: */ \
216 "state @ if " /* if in compiling state: */ \
217 "1 postpone literal " /* pass 1 flag to indicate compile */ \
218 "@ compile, " /* compile in previous definition */ \
219 "postpone throw " /* throw stack-returned result */ \
220 "else " /* if in interpreting state: */ \
221 "0 swap " /* pass 0 flag to indicate interpret */ \
222 "@ execute " /* call previous definition */ \
223 "throw " /* throw stack-returned result */ \
227 * Initialise the Forth interpreter, create all our commands as words.
232 struct bootblk_command **cmdp;
233 char create_buf[41]; /* 31 characters-long builtins */
236 ficlInitSystem(10000); /* Default dictionary ~4000 cells */
239 /* Put all private definitions in a "builtins" vocabulary */
240 ficlExec(bf_vm, "vocabulary builtins also builtins definitions");
242 /* Builtin constructor word */
243 ficlExec(bf_vm, BUILTIN_CONSTRUCTOR);
245 /* make all commands appear as Forth words */
246 SET_FOREACH(cmdp, Xcommand_set) {
247 ficlBuild((*cmdp)->c_name, bf_command, FW_DEFAULT);
248 ficlExec(bf_vm, "forth definitions builtins");
249 sprintf(create_buf, "builtin: %s", (*cmdp)->c_name);
250 ficlExec(bf_vm, create_buf);
251 ficlExec(bf_vm, "builtins definitions");
253 ficlExec(bf_vm, "only forth definitions");
255 /* Export some version numbers so that code can detect the loader/host version */
256 ficlSetEnv("FreeBSD_version", __FreeBSD_version);
257 ficlSetEnv("loader_version",
258 (bootprog_rev[0] - '0') * 10 + (bootprog_rev[2] - '0'));
260 /* try to load and run init file if present */
261 if ((fd = open("/boot/boot.4th", O_RDONLY)) != -1) {
262 (void)ficlExecFD(bf_vm, fd);
266 /* Do this last, so /boot/boot.4th can change it */
267 pInterp = ficlLookup("interpret");
271 * Feed a line of user input to the Forth interpreter
278 result = ficlExec(bf_vm, line);
280 DEBUG("ficlExec '%s' = %d", line, result);
288 printf("No where to leave to!\n");
291 printf("Aborted!\n");
294 printf("Parse error!\n");
297 /* Hopefully, all other codes filled this buffer */
298 printf("%s\n", command_errmsg);
301 if (result == VM_USEREXIT)
302 panic("interpreter exit");
303 setenv("interpret", bf_vm->state ? "" : "ok", 1);