/* * Copyright (c) 1998 Michael Smith * 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. * * $FreeBSD$ */ #include /* to pick up __FreeBSD_version */ #include #include #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_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; ficlInitSystem(10000); /* Default dictionary ~4000 cells */ bf_vm = ficlNewVM(); /* 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((*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("FreeBSD_version", __FreeBSD_version); ficlSetEnv("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("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; }