File:  [DragonFly] / src / sys / boot / common / interp_forth.c
Revision 1.3: download - view: text, annotated - select for diffs
Mon Nov 10 06:08:31 2003 UTC (10 years, 8 months ago) by dillon
Branches: MAIN
CVS tags: HEAD
Fully synchronize sys/boot from FreeBSD-5.x, but add / to the module path
so /kernel will be found and loaded instead of /boot/kernel.  This will
give us all the capabilities of the FreeBSD-5 boot code including AMD64 and
ELF64 support.

As part of this work, rather then try to adjust ufs/fs.h and friends to get
UFS2 info I instead copied the fs.h and friends from FreeBSD-5 into the
sys/boot subtree

Additionally, import Peter Wemm's linker set improvements from FreeBSD-5.x.
They happen to be compatible with GCC 2.95.x and it allows very few changes
to be made to the boot code.

NOTE!  UFS2 support is not enabled by default as of this commit because it
causes boot2 to run over its limit by 88 bytes.

/*-
 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: src/sys/boot/common/interp_forth.c,v 1.23 2003/08/25 23:30:41 obrien Exp $
 * $DragonFly: src/sys/boot/common/interp_forth.c,v 1.3 2003/11/10 06:08:31 dillon Exp $
 */

#include <sys/param.h>		/* to pick up __FreeBSD_version */
#include <string.h>
#include <stand.h>
#include "bootstrap.h"
#include "ficl.h"

extern char bootprog_rev[];

/* #define BFORTH_DEBUG */

#ifdef BFORTH_DEBUG
# define DEBUG(fmt, args...)	printf("%s: " fmt "\n" , __func__ , ## args)
#else
# define DEBUG(fmt, args...)
#endif

/*
 * Eventually, all builtin commands throw codes must be defined
 * elsewhere, possibly bootstrap.h. For now, just this code, used
 * just in this file, it is getting defined.
 */
#define BF_PARSE 100

/*
 * BootForth   Interface to Ficl Forth interpreter.
 */

FICL_SYSTEM *bf_sys;
FICL_VM	*bf_vm;
FICL_WORD *pInterp;

/*
 * Shim for taking commands from BF and passing them out to 'standard'
 * argv/argc command functions.
 */
static void
bf_command(FICL_VM *vm)
{
    char			*name, *line, *tail, *cp;
    size_t			len;
    struct bootblk_command	**cmdp;
    bootblk_cmd_t		*cmd;
    int				nstrings, i;
    int				argc, result;
    char			**argv;

    /* Get the name of the current word */
    name = vm->runningWord->name;
    
    /* Find our command structure */
    cmd = NULL;
    SET_FOREACH(cmdp, Xcommand_set) {
	if (((*cmdp)->c_name != NULL) && !strcmp(name, (*cmdp)->c_name))
	    cmd = (*cmdp)->c_fn;
    }
    if (cmd == NULL)
	panic("callout for unknown command '%s'", name);
   
    /* Check whether we have been compiled or are being interpreted */
    if (stackPopINT(vm->pStack)) {
	/*
	 * Get parameters from stack, in the format:
	 * an un ... a2 u2 a1 u1 n --
	 * Where n is the number of strings, a/u are pairs of
	 * address/size for strings, and they will be concatenated
	 * in LIFO order.
	 */
	nstrings = stackPopINT(vm->pStack);
	for (i = 0, len = 0; i < nstrings; i++)
	    len += stackFetch(vm->pStack, i * 2).i + 1;
	line = malloc(strlen(name) + len + 1);
	strcpy(line, name);

	if (nstrings)
	    for (i = 0; i < nstrings; i++) {
		len = stackPopINT(vm->pStack);
		cp = stackPopPtr(vm->pStack);
		strcat(line, " ");
		strncat(line, cp, len);
	    }
    } else {
	/* Get remainder of invocation */
	tail = vmGetInBuf(vm);
	for (cp = tail, len = 0; cp != vm->tib.end && *cp != 0 && *cp != '\n'; cp++, len++)
	    ;
    
	line = malloc(strlen(name) + len + 2);
	strcpy(line, name);
	if (len > 0) {
	    strcat(line, " ");
	    strncat(line, tail, len);
	    vmUpdateTib(vm, tail + len);
	}
    }
    DEBUG("cmd '%s'", line);
    
    command_errmsg = command_errbuf;
    command_errbuf[0] = 0;
    if (!parse(&argc, &argv, line)) {
	result = (cmd)(argc, argv);
	free(argv);
    } else {
	result=BF_PARSE;
    }
    free(line);
    /* This is going to be thrown!!! */
    stackPushINT(vm->pStack,result);
}

/*
 * Replace a word definition (a builtin command) with another
 * one that:
 *
 *        - Throw error results instead of returning them on the stack
 *        - Pass a flag indicating whether the word was compiled or is
 *          being interpreted.
 *
 * There is one major problem with builtins that cannot be overcome
 * in anyway, except by outlawing it. We want builtins to behave
 * differently depending on whether they have been compiled or they
 * are being interpreted. Notice that this is *not* the interpreter's
 * current state. For example:
 *
 * : example ls ; immediate
 * : problem example ;		\ "ls" gets executed while compiling
 * example			\ "ls" gets executed while interpreting
 *
 * Notice that, though the current state is different in the two
 * invocations of "example", in both cases "ls" has been
 * *compiled in*, which is what we really want.
 *
 * The problem arises when you tick the builtin. For example:
 *
 * : example-1 ['] ls postpone literal ; immediate
 * : example-2 example-1 execute ; immediate
 * : problem example-2 ;
 * example-2
 *
 * We have no way, when we get EXECUTEd, of knowing what our behavior
 * should be. Thus, our only alternative is to "outlaw" this. See RFI
 * 0007, and ANS Forth Standard's appendix D, item 6.7 for a related
 * problem, concerning compile semantics.
 *
 * The problem is compounded by the fact that "' builtin CATCH" is valid
 * and desirable. The only solution is to create an intermediary word.
 * For example:
 *
 * : my-ls ls ;
 * : example ['] my-ls catch ;
 *
 * So, with the below implementation, here is a summary of the behavior
 * of builtins:
 *
 * ls -l				\ "interpret" behavior, ie,
 *					\ takes parameters from TIB
 * : ex-1 s" -l" 1 ls ;			\ "compile" behavior, ie,
 *					\ takes parameters from the stack
 * : ex-2 ['] ls catch ; immediate	\ undefined behavior
 * : ex-3 ['] ls catch ;		\ undefined behavior
 * ex-2 ex-3				\ "interpret" behavior,
 *					\ catch works
 * : ex-4 ex-2 ;			\ "compile" behavior,
 *					\ catch does not work
 * : ex-5 ex-3 ; immediate		\ same as ex-2
 * : ex-6 ex-3 ;			\ same as ex-3
 * : ex-7 ['] ex-1 catch ;		\ "compile" behavior,
 *					\ catch works
 * : ex-8 postpone ls ;	immediate	\ same as ex-2
 * : ex-9 postpone ls ;			\ same as ex-3
 *
 * As the definition below is particularly tricky, and it's side effects
 * must be well understood by those playing with it, I'll be heavy on
 * the comments.
 *
 * (if you edit this definition, pay attention to trailing spaces after
 *  each word -- I warned you! :-) )
 */
#define BUILTIN_CONSTRUCTOR \
": builtin: "		\
  ">in @ "		/* save the tib index pointer */ \
  "' "			/* get next word's xt */ \
  "swap >in ! "		/* point again to next word */ \
  "create "		/* create a new definition of the next word */ \
  ", "			/* save previous definition's xt */ \
  "immediate "		/* make the new definition an immediate word */ \
			\
  "does> "		/* Now, the *new* definition will: */ \
  "state @ if "		/* if in compiling state: */ \
    "1 postpone literal "	/* pass 1 flag to indicate compile */ \
    "@ compile, "		/* compile in previous definition */ \
    "postpone throw "		/* throw stack-returned result */ \
  "else "		/* if in interpreting state: */ \
    "0 swap "			/* pass 0 flag to indicate interpret */ \
    "@ execute "		/* call previous definition */ \
    "throw "			/* throw stack-returned result */ \
  "then ; "

/*
 * Initialise the Forth interpreter, create all our commands as words.
 */
void
bf_init(void)
{
    struct bootblk_command	**cmdp;
    char create_buf[41];	/* 31 characters-long builtins */
    int fd;
   
    bf_sys = ficlInitSystem(10000);	/* Default dictionary ~4000 cells */
    bf_vm = ficlNewVM(bf_sys);

    /* Put all private definitions in a "builtins" vocabulary */
    ficlExec(bf_vm, "vocabulary builtins also builtins definitions");

    /* Builtin constructor word  */
    ficlExec(bf_vm, BUILTIN_CONSTRUCTOR);

    /* make all commands appear as Forth words */
    SET_FOREACH(cmdp, Xcommand_set) {
	ficlBuild(bf_sys, (char *)(*cmdp)->c_name, bf_command, FW_DEFAULT);
	ficlExec(bf_vm, "forth definitions builtins");
	sprintf(create_buf, "builtin: %s", (*cmdp)->c_name);
	ficlExec(bf_vm, create_buf);
	ficlExec(bf_vm, "builtins definitions");
    }
    ficlExec(bf_vm, "only forth definitions");

    /* Export some version numbers so that code can detect the loader/host version */
    ficlSetEnv(bf_sys, "FreeBSD_version", __FreeBSD_version);
    ficlSetEnv(bf_sys, "loader_version", 
	       (bootprog_rev[0] - '0') * 10 + (bootprog_rev[2] - '0'));

    /* try to load and run init file if present */
    if ((fd = open("/boot/boot.4th", O_RDONLY)) != -1) {
	(void)ficlExecFD(bf_vm, fd);
	close(fd);
    }

    /* Do this last, so /boot/boot.4th can change it */
    pInterp = ficlLookup(bf_sys, "interpret");
}

/*
 * Feed a line of user input to the Forth interpreter
 */
int
bf_run(char *line)
{
    int		result;

    result = ficlExec(bf_vm, line);

    DEBUG("ficlExec '%s' = %d", line, result);
    switch (result) {
    case VM_OUTOFTEXT:
    case VM_ABORTQ:
    case VM_QUIT:
    case VM_ERREXIT:
	break;
    case VM_USEREXIT:
	printf("No where to leave to!\n");
	break;
    case VM_ABORT:
	printf("Aborted!\n");
	break;
    case BF_PARSE:
	printf("Parse error!\n");
	break;
    default:
        /* Hopefully, all other codes filled this buffer */
	printf("%s\n", command_errmsg);
    }
    
    if (result == VM_USEREXIT)
	panic("interpreter exit");
    setenv("interpret", bf_vm->state ? "" : "OK", 1);

    return result;
}