306 lines
9.3 KiB
C
306 lines
9.3 KiB
C
/*
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* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/param.h> /* to pick up __FreeBSD_version */
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#include <string.h>
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#include <stand.h>
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#include "bootstrap.h"
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#include "ficl.h"
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extern char bootprog_rev[];
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/* #define BFORTH_DEBUG */
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#ifdef BFORTH_DEBUG
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# define DEBUG(fmt, args...) printf("%s: " fmt "\n" , __func__ , ## args)
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#else
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# define DEBUG(fmt, args...)
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#endif
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/*
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* Eventually, all builtin commands throw codes must be defined
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* elsewhere, possibly bootstrap.h. For now, just this code, used
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* just in this file, it is getting defined.
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*/
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#define BF_PARSE 100
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/*
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* BootForth Interface to Ficl Forth interpreter.
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*/
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FICL_VM *bf_vm;
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FICL_WORD *pInterp;
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/*
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* Shim for taking commands from BF and passing them out to 'standard'
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* argv/argc command functions.
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*/
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static void
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bf_command(FICL_VM *vm)
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{
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char *name, *line, *tail, *cp;
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size_t len;
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struct bootblk_command **cmdp;
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bootblk_cmd_t *cmd;
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int nstrings, i;
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int argc, result;
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char **argv;
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/* Get the name of the current word */
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name = vm->runningWord->name;
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/* Find our command structure */
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cmd = NULL;
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SET_FOREACH(cmdp, Xcommand_set) {
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if (((*cmdp)->c_name != NULL) && !strcmp(name, (*cmdp)->c_name))
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cmd = (*cmdp)->c_fn;
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}
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if (cmd == NULL)
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panic("callout for unknown command '%s'", name);
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/* Check whether we have been compiled or are being interpreted */
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if (stackPopINT(vm->pStack)) {
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/*
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* Get parameters from stack, in the format:
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* an un ... a2 u2 a1 u1 n --
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* Where n is the number of strings, a/u are pairs of
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* address/size for strings, and they will be concatenated
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* in LIFO order.
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*/
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nstrings = stackPopINT(vm->pStack);
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for (i = 0, len = 0; i < nstrings; i++)
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len += stackFetch(vm->pStack, i * 2).i + 1;
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line = malloc(strlen(name) + len + 1);
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strcpy(line, name);
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if (nstrings)
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for (i = 0; i < nstrings; i++) {
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len = stackPopINT(vm->pStack);
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cp = stackPopPtr(vm->pStack);
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strcat(line, " ");
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strncat(line, cp, len);
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}
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} else {
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/* Get remainder of invocation */
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tail = vmGetInBuf(vm);
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for (cp = tail, len = 0; cp != vm->tib.end && *cp != 0 && *cp != '\n'; cp++, len++)
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;
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line = malloc(strlen(name) + len + 2);
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strcpy(line, name);
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if (len > 0) {
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strcat(line, " ");
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strncat(line, tail, len);
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vmUpdateTib(vm, tail + len);
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}
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}
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DEBUG("cmd '%s'", line);
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command_errmsg = command_errbuf;
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command_errbuf[0] = 0;
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if (!parse(&argc, &argv, line)) {
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result = (cmd)(argc, argv);
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free(argv);
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} else {
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result=BF_PARSE;
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}
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free(line);
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/* This is going to be thrown!!! */
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stackPushINT(vm->pStack,result);
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}
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/*
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* Replace a word definition (a builtin command) with another
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* one that:
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*
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* - Throw error results instead of returning them on the stack
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* - Pass a flag indicating whether the word was compiled or is
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* being interpreted.
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*
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* There is one major problem with builtins that cannot be overcome
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* in anyway, except by outlawing it. We want builtins to behave
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* differently depending on whether they have been compiled or they
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* are being interpreted. Notice that this is *not* the interpreter's
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* current state. For example:
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*
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* : example ls ; immediate
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* : problem example ; \ "ls" gets executed while compiling
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* example \ "ls" gets executed while interpreting
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*
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* Notice that, though the current state is different in the two
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* invocations of "example", in both cases "ls" has been
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* *compiled in*, which is what we really want.
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*
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* The problem arises when you tick the builtin. For example:
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*
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* : example-1 ['] ls postpone literal ; immediate
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* : example-2 example-1 execute ; immediate
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* : problem example-2 ;
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* example-2
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*
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* We have no way, when we get EXECUTEd, of knowing what our behavior
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* should be. Thus, our only alternative is to "outlaw" this. See RFI
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* 0007, and ANS Forth Standard's appendix D, item 6.7 for a related
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* problem, concerning compile semantics.
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*
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* The problem is compounded by the fact that "' builtin CATCH" is valid
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* and desirable. The only solution is to create an intermediary word.
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* For example:
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*
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* : my-ls ls ;
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* : example ['] my-ls catch ;
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*
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* So, with the below implementation, here is a summary of the behavior
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* of builtins:
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*
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* ls -l \ "interpret" behavior, ie,
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* \ takes parameters from TIB
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* : ex-1 s" -l" 1 ls ; \ "compile" behavior, ie,
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* \ takes parameters from the stack
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* : ex-2 ['] ls catch ; immediate \ undefined behavior
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* : ex-3 ['] ls catch ; \ undefined behavior
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* ex-2 ex-3 \ "interpret" behavior,
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* \ catch works
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* : ex-4 ex-2 ; \ "compile" behavior,
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* \ catch does not work
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* : ex-5 ex-3 ; immediate \ same as ex-2
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* : ex-6 ex-3 ; \ same as ex-3
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* : ex-7 ['] ex-1 catch ; \ "compile" behavior,
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* \ catch works
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* : ex-8 postpone ls ; immediate \ same as ex-2
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* : ex-9 postpone ls ; \ same as ex-3
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*
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* As the definition below is particularly tricky, and it's side effects
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* must be well understood by those playing with it, I'll be heavy on
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* the comments.
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*
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* (if you edit this definition, pay attention to trailing spaces after
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* each word -- I warned you! :-) )
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*/
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#define BUILTIN_CONSTRUCTOR \
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": builtin: " \
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">in @ " /* save the tib index pointer */ \
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"' " /* get next word's xt */ \
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"swap >in ! " /* point again to next word */ \
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"create " /* create a new definition of the next word */ \
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", " /* save previous definition's xt */ \
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"immediate " /* make the new definition an immediate word */ \
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\
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"does> " /* Now, the *new* definition will: */ \
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"state @ if " /* if in compiling state: */ \
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"1 postpone literal " /* pass 1 flag to indicate compile */ \
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"@ compile, " /* compile in previous definition */ \
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"postpone throw " /* throw stack-returned result */ \
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"else " /* if in interpreting state: */ \
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"0 swap " /* pass 0 flag to indicate interpret */ \
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"@ execute " /* call previous definition */ \
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"throw " /* throw stack-returned result */ \
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"then ; "
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/*
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* Initialise the Forth interpreter, create all our commands as words.
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*/
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void
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bf_init(void)
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{
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struct bootblk_command **cmdp;
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char create_buf[41]; /* 31 characters-long builtins */
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int fd;
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ficlInitSystem(10000); /* Default dictionary ~4000 cells */
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bf_vm = ficlNewVM();
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/* Put all private definitions in a "builtins" vocabulary */
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ficlExec(bf_vm, "vocabulary builtins also builtins definitions");
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/* Builtin constructor word */
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ficlExec(bf_vm, BUILTIN_CONSTRUCTOR);
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/* make all commands appear as Forth words */
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SET_FOREACH(cmdp, Xcommand_set) {
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ficlBuild((*cmdp)->c_name, bf_command, FW_DEFAULT);
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ficlExec(bf_vm, "forth definitions builtins");
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sprintf(create_buf, "builtin: %s", (*cmdp)->c_name);
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ficlExec(bf_vm, create_buf);
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ficlExec(bf_vm, "builtins definitions");
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}
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ficlExec(bf_vm, "only forth definitions");
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/* Export some version numbers so that code can detect the loader/host version */
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ficlSetEnv("FreeBSD_version", __FreeBSD_version);
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ficlSetEnv("loader_version",
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(bootprog_rev[0] - '0') * 10 + (bootprog_rev[2] - '0'));
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/* try to load and run init file if present */
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if ((fd = open("/boot/boot.4th", O_RDONLY)) != -1) {
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(void)ficlExecFD(bf_vm, fd);
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close(fd);
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}
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/* Do this last, so /boot/boot.4th can change it */
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pInterp = ficlLookup("interpret");
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}
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/*
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* Feed a line of user input to the Forth interpreter
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*/
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int
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bf_run(char *line)
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{
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int result;
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result = ficlExec(bf_vm, line);
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DEBUG("ficlExec '%s' = %d", line, result);
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switch (result) {
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case VM_OUTOFTEXT:
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case VM_ABORTQ:
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case VM_QUIT:
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case VM_ERREXIT:
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break;
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case VM_USEREXIT:
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printf("No where to leave to!\n");
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break;
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case VM_ABORT:
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printf("Aborted!\n");
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break;
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case BF_PARSE:
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printf("Parse error!\n");
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break;
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default:
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/* Hopefully, all other codes filled this buffer */
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printf("%s\n", command_errmsg);
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}
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if (result == VM_USEREXIT)
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panic("interpreter exit");
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setenv("interpret", bf_vm->state ? "" : "OK", 1);
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return result;
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}
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