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retroforth/vm/nga-c/retro-unix.c
crc 3d276b7be4 nga-c: remove a variable in invalid_opcode() 
FossilOrigin-Name: 5566b4671f5af90202b8493e14142acd7e902732410a3d071040310721e7d8d6
2021-01-24 05:16:18 +00:00

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/*---------------------------------------------------------------------
RETRO is a personal, minimalistic forth with a pragmatic focus
This implements Nga, the virtual machine at the heart of RETRO. It
includes a number of I/O interfaces, extensive commentary, and has
been refined by over a decade of use and development.
Copyright (c) 2008 - 2020, Charles Childers
Portions are based on Ngaro, which was additionally copyrighted by
the following:
Copyright (c) 2009 - 2010, Luke Parrish
Copyright (c) 2010, Marc Simpson
Copyright (c) 2010, Jay Skeer
Copyright (c) 2011, Kenneth Keating
---------------------------------------------------------------------*/
/*---------------------------------------------------------------------
C Headers
---------------------------------------------------------------------*/
#include <ctype.h>
#include <errno.h>
#include <math.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <limits.h>
#include <fcntl.h>
/*---------------------------------------------------------------------
Configuration
---------------------------------------------------------------------*/
#include "config.h"
#include "prototypes.h"
/*---------------------------------------------------------------------
Image, Stack, and VM variables
---------------------------------------------------------------------*/
CELL sp, rp, ip; /* Stack & instruction pointers */
CELL data[STACK_DEPTH]; /* The data stack */
CELL address[ADDRESSES]; /* The address stack */
CELL memory[IMAGE_SIZE + 1]; /* The memory for the image */
#define TOS data[sp] /* Shortcut for top item on stack */
#define NOS data[sp-1] /* Shortcut for second item on stack */
#define TORS address[rp] /* Shortcut for top item on address stack */
/*---------------------------------------------------------------------
Markers for code & test blocks
---------------------------------------------------------------------*/
char code_start[33], code_end[33], test_start[33], test_end[33];
/*---------------------------------------------------------------------
Populate The I/O Device Tables
---------------------------------------------------------------------*/
typedef void (*Handler)(void);
Handler IO_deviceHandlers[] = {
io_output_handler,
io_keyboard_handler,
io_floatingpoint_handler,
io_filesystem_handler,
io_clock_handler,
io_unix_handler,
io_scripting_handler,
io_random,
io_image,
};
Handler IO_queryHandlers[] = {
io_output_query,
io_keyboard_query,
io_floatingpoint_query,
io_filesystem_query,
io_clock_query,
io_unix_query,
io_scripting_query,
io_random_query,
io_image_query,
};
/*---------------------------------------------------------------------
Variables Related To Image Introspection
---------------------------------------------------------------------*/
CELL Compiler;
CELL Dictionary;
CELL NotFound;
CELL interpret;
/*---------------------------------------------------------------------
Global Variables
---------------------------------------------------------------------*/
char string_data[8192];
char **sys_argv;
int sys_argc;
int silence_input;
char scripting_sources[64][8192];
int current_source;
int perform_abort;
/*---------------------------------------------------------------------
Embed The Image and Devices
---------------------------------------------------------------------*/
#include "retro-image.c"
#include "bsd-strl.c"
#include "dev-floatingpoint.c"
#include "dev-image.c"
#include "dev-files.c"
#include "dev-unix.c"
#include "dev-clock.c"
#include "dev-rng.c"
/*---------------------------------------------------------------------
Now on to I/O and extensions!
RRE provides a lot of additional functionality over the base RETRO
system. First up is support for files.
The RRE file model is intended to be similar to that of the standard
C libraries and wraps fopen(), fclose(), etc.
---------------------------------------------------------------------*/
void io_output_handler() {
putc(stack_pop(), stdout);
fflush(stdout);
}
void io_output_query() {
stack_push(0);
stack_push(0);
}
/*=====================================================================*/
void io_keyboard_handler() {
stack_push(getc(stdin));
if (TOS == 127) TOS = 8;
}
void io_keyboard_query() {
stack_push(0);
stack_push(1);
}
/*=====================================================================*/
/*---------------------------------------------------------------------
Scripting Support
---------------------------------------------------------------------*/
CELL currentLine;
CELL ignoreToEOL;
CELL ignoreToEOF;
void scripting_arg() {
CELL a, b;
a = stack_pop();
b = stack_pop();
stack_push(string_inject(sys_argv[a + 2], b));
}
void scripting_arg_count() {
stack_push(sys_argc - 2);
}
void scripting_include() {
include_file(string_extract(stack_pop()), 0);
}
void scripting_name() {
stack_push(string_inject(sys_argv[1], stack_pop()));
}
/* addeded in scripting i/o device, revision 1 */
void scripting_source() {
stack_push(string_inject(scripting_sources[current_source], stack_pop()));
}
void scripting_line() {
stack_push(currentLine + 1);
}
void scripting_ignore_to_eol() {
ignoreToEOL = -1;
}
void scripting_ignore_to_eof() {
ignoreToEOF = -1;
}
void scripting_abort() {
scripting_ignore_to_eol();
scripting_ignore_to_eof();
perform_abort = -1;
}
void carry_out_abort() {
ip = IMAGE_SIZE + 1;
rp = 0;
sp = 0;
fsp = 0;
afsp = 0;
if (current_source > 0) {
scripting_abort();
return;
}
perform_abort = 0;
current_source = 0;
}
Handler ScriptingActions[] = {
scripting_arg_count,
scripting_arg,
scripting_include,
scripting_name,
scripting_source,
scripting_line,
scripting_ignore_to_eol,
scripting_ignore_to_eof,
scripting_abort
};
void io_scripting_query() {
stack_push(2);
stack_push(9);
}
void io_scripting_handler() {
ScriptingActions[stack_pop()]();
}
/*=====================================================================*/
/*---------------------------------------------------------------------
With these out of the way, I implement `execute`, which takes an
address and runs the code at it. This has a couple of interesting
bits.
This will also exit if the address stack depth is zero (meaning that
the word being run, and it's dependencies) are finished.
---------------------------------------------------------------------*/
void invalid_opcode(CELL opcode) {
CELL a, i;
printf("\nERROR (nga/execute): Invalid instruction!\n");
printf("At %lld, opcode %lld\n", (long long)ip, (long long)opcode);
printf("Instructions: ");
a = opcode;
for (i = 0; i < 4; i++) {
printf("%lldd ", (long long)a & 0xFF);
a = a >> 8;
}
printf("\n");
exit(1);
}
void execute(CELL cell, int silent) {
CELL token;
CELL opcode;
silence_input = silent;
if (rp == 0)
rp = 1;
else {
rp++;
TORS = -1;
rp++;
}
ip = cell;
token = TIB;
while (ip < IMAGE_SIZE) {
if (perform_abort == 0) {
if (TORS == -1) {
rp--;
ip = TORS;
return;
}
if (ip == NotFound) {
printf("\nERROR: Word Not Found: ");
printf("`%s`\n\n", string_extract(token));
}
if (ip == interpret) {
token = TOS;
}
opcode = memory[ip];
if (validate_opcode_bundle(opcode) != 0) {
process_opcode_bundle(opcode);
} else {
invalid_opcode(opcode);
}
#ifndef NOCHECKS
if (sp < 0 || sp > STACK_DEPTH) {
printf("\nERROR (nga/execute): Stack Limits Exceeded!\n");
printf("At %lld, opcode %lld. sp = %lld\n", (long long)ip, (long long)opcode, (long long)sp);
exit(1);
}
if (rp < 0 || rp > ADDRESSES) {
printf("\nERROR (nga/execute): Address Stack Limits Exceeded!\n");
printf("At %lld, opcode %lld. rp = %lld\n", (long long)ip, (long long)opcode, (long long)rp);
exit(1);
}
#endif
ip++;
if (rp == 0)
ip = IMAGE_SIZE;
} else {
carry_out_abort();
}
}
}
/*---------------------------------------------------------------------
RETRO's `interpret` word expects a token on the stack. This next
function copies a token to the `TIB` (text input buffer) and then
calls `interpret` to process it.
---------------------------------------------------------------------*/
void evaluate(char *s, int silent) {
if (strlen(s) == 0) return;
string_inject(s, TIB);
stack_push(TIB);
execute(interpret, silent);
}
/*---------------------------------------------------------------------
`read_token` reads a token from the specified file. It will stop on
a whitespace or newline. It also tries to handle backspaces, though
the success of this depends on how your terminal is configured.
---------------------------------------------------------------------*/
int not_eol(int c) {
return (c != 10) && (c != 13) && (c != 32) && (c != EOF) && (c != 0);
}
void read_token(FILE *file, char *token_buffer, int echo) {
int ch = getc(file);
int count = 0;
if (echo != 0)
putchar(ch);
while (not_eol(ch)) {
if ((ch == 8 || ch == 127) && count > 0) {
count--;
if (echo != 0) {
putchar(8);
putchar(32);
putchar(8);
}
} else {
token_buffer[count++] = ch;
}
ch = getc(file);
if (echo != 0)
putchar(ch);
}
token_buffer[count] = '\0';
}
/*---------------------------------------------------------------------
Display the Stack Contents
---------------------------------------------------------------------*/
void dump_stack() {
CELL i;
if (sp == 0) return;
printf("\nStack: ");
for (i = 1; i <= sp; i++) {
if (i == sp)
printf("[ TOS: %lld ]", (long long)data[i]);
else
printf("%lld ", (long long)data[i]);
}
printf("\n");
}
/*---------------------------------------------------------------------
RRE is primarily intended to be used in a batch or scripting model.
The `include_file()` function will be used to read the code in the
file, evaluating it as encountered.
I enforce a literate model, with code in fenced blocks. E.g.,
# This is a test
Display "Hello, World!"
~~~
'Hello,_World! puts nl
~~~
RRE will ignore anything outside the `~~~` blocks. To identify if the
current token is the start or end of a block, I provide a `fenced()`
function.
---------------------------------------------------------------------*/
/* Check to see if a line is a fence boundary.
This will check code blocks in all cases, and test blocks
if tests_enabled is set to a non-zero value. */
int fence_boundary(char *buffer, int tests_enabled) {
int flag = 1;
if (strcmp(buffer, code_start) == 0) { flag = -1; }
if (strcmp(buffer, code_end) == 0) { flag = -1; }
if (tests_enabled == 0) { return flag; }
if (strcmp(buffer, test_start) == 0) { flag = -1; }
if (strcmp(buffer, test_end) == 0) { flag = -1; }
return flag;
}
/*---------------------------------------------------------------------
And now for the actual `include_file()` function.
---------------------------------------------------------------------*/
void read_line(FILE *file, char *token_buffer) {
int ch = getc(file);
int count = 0;
while ((ch != 10) && (ch != 13) && (ch != EOF) && (ch != 0)) {
token_buffer[count++] = ch;
ch = getc(file);
}
token_buffer[count] = '\0';
}
int count_tokens(char *line) {
char ch = line[0];
int count = 1;
while (*line++) {
ch = line[0];
if (isspace(ch))
count++;
}
return count;
}
void include_file(char *fname, int run_tests) {
int inBlock = 0; /* Tracks status of in/out of block */
char source[64 * 1024]; /* Token buffer [about 64K] */
char line[64 * 1024]; /* Line buffer [about 64K] */
char fence[33]; /* Used with `fence_boundary()` */
long offset = 0;
CELL at = 0;
int tokens = 0;
FILE *fp; /* Open the file. If not found, */
fp = fopen(fname, "r"); /* exit. */
if (fp == NULL)
return;
current_source++;
bsd_strlcpy(scripting_sources[current_source], fname, 8192);
ignoreToEOF = 0;
while (!feof(fp) && (ignoreToEOF == 0)) { /* Loop through the file */
ignoreToEOL = 0;
offset = ftell(fp);
read_line(fp, line);
fseek(fp, offset, SEEK_SET);
tokens = count_tokens(line);
while (tokens > 0 && ignoreToEOL == 0) {
tokens--;
read_token(fp, source, 0);
bsd_strlcpy(fence, source, 32); /* Copy the first three characters */
if (fence_boundary(fence, run_tests) == -1) {
if (inBlock == 0)
inBlock = 1;
else
inBlock = 0;
} else {
if (inBlock == 1) {
currentLine = at;
evaluate(source, -1);
currentLine = at;
}
}
}
if (ignoreToEOL == -1)
read_line(fp, line);
at++;
}
current_source--;
ignoreToEOF = 0;
fclose(fp);
if (perform_abort == -1) {
carry_out_abort();
}
}
/*---------------------------------------------------------------------
`help()` displays a summary of the command line arguments RRE allows.
This is invoked using `rre -h`
---------------------------------------------------------------------*/
void help(char *exename) {
printf("Scripting Usage: %s filename\n\n", exename);
printf("Interactive Usage: %s [-h] [-i] [-f filename] [-t]\n\n", exename);
printf("Valid Arguments:\n\n");
printf(" -h\n");
printf(" Display this help text\n");
printf(" -i\n");
printf(" Launches in interactive mode\n");
printf(" -s\n");
printf(" Suppress the startup banner in interactive mode. Implies -i.\n");
printf(" -f filename\n");
printf(" Run the contents of the specified file\n");
printf(" -u filename\n");
printf(" Use the image in the specified file instead of the internal one\n");
printf(" -r filename\n");
printf(" Use the image in the specified file instead of the internal one and run the code in it\n");
printf(" -t\n");
printf(" Run tests (in ``` blocks) in any loaded files\n\n");
}
/*---------------------------------------------------------------------
`initialize()` sets up Nga and loads the image (from the array in
`image.c`) to memory.
---------------------------------------------------------------------*/
void initialize() {
CELL i;
prepare_vm();
for (i = 0; i < ngaImageCells; i++)
memory[i] = ngaImage[i];
}
/*---------------------------------------------------------------------
`arg_is()` exists to aid in readability. It compares the first actual
command line argument to a string and returns a boolean flag.
---------------------------------------------------------------------*/
int arg_is(char *argv, char *t) {
return strcmp(argv, t) == 0;
}
/*---------------------------------------------------------------------
Main Entry Point
---------------------------------------------------------------------*/
enum flags {
FLAG_HELP, FLAG_RUN_TESTS, FLAG_INCLUDE, FLAG_INTERACTIVE, FLAG_SILENT,
FLAG_RUN,
};
int main(int argc, char **argv) {
int i;
int modes[16];
char *files[16];
int fsp;
int run_tests;
initialize(); /* Initialize Nga & image */
strcpy(code_start, "~~~");
strcpy(code_end, "~~~");
strcpy(test_start, "```");
strcpy(test_end, "```");
/* Setup variables related to the scripting device */
currentLine = 0; /* Current Line # for script */
current_source = 0; /* Current file being run */
perform_abort = 0; /* Carry out abort procedure */
sys_argc = argc; /* Point the global argc and */
sys_argv = argv; /* argv to the actual ones */
bsd_strlcpy(scripting_sources[0], "/dev/stdin", 8192);
ignoreToEOL = 0;
ignoreToEOF = 0;
if (argc >= 2 && argv[1][0] != '-') {
update_rx();
include_file(argv[1], 0); /* If no flags were passed, */
if (sp >= 1) dump_stack(); /* load the file specified, */
exit(0); /* and exit */
}
/* Clear startup modes */
for (i = 0; i < 16; i++)
modes[i] = 0;
/* Clear startup files */
for (i = 0; i < 16; i++)
files[i] = "\0";
fsp = 0;
run_tests = 0;
if (argc <= 1) modes[FLAG_INTERACTIVE] = 1;
/* Process Arguments */
for (i = 1; i < argc; i++) {
if (strcmp(argv[i], "-h") == 0) {
help(argv[0]);
exit(0);
} else if (strcmp(argv[i], "-i") == 0) {
modes[FLAG_INTERACTIVE] = 1;
} else if (strcmp(argv[i], "-s") == 0) {
modes[FLAG_INTERACTIVE] = 1;
modes[FLAG_SILENT] = 1;
} else if (strcmp(argv[i], "-f") == 0) {
files[fsp] = argv[i + 1];
fsp++;
i++;
} else if (strcmp(argv[i], "-u") == 0) {
i++;
load_image(argv[i]);
} else if (strcmp(argv[i], "-r") == 0) {
i++;
load_image(argv[i]);
modes[FLAG_RUN] = 1;
} else if (strcmp(argv[i], "-t") == 0) {
modes[FLAG_RUN_TESTS] = 1;
run_tests = 1;
} else if (arg_is(argv[i], "--code-start") || arg_is(argv[i], "-cs")) {
i++;
strcpy(code_start, argv[i]);
} else if (arg_is(argv[i], "--code-end") || arg_is(argv[i], "-ce")) {
i++;
strcpy(code_end, argv[i]);
} else if (arg_is(argv[i], "--test-start") || arg_is(argv[i], "-ts")) {
i++;
strcpy(test_start, argv[i]);
} else if (arg_is(argv[i], "--test-end") || arg_is(argv[i], "-te")) {
i++;
strcpy(test_end, argv[i]);
}
}
update_rx();
/* Include Startup Files */
for (i = 0; i < fsp; i++) {
if (strcmp(files[i], "\0") != 0)
include_file(files[i], run_tests);
}
/* Set Image Flags for NoEcho if started with `-s` */
if (modes[FLAG_SILENT] == 1)
memory[d_xt_for("NoEcho", Dictionary)] = -1;
/* Run the Listener (if interactive mode was set) */
if (modes[FLAG_INTERACTIVE] == 1) {
execute(0, -1);
}
if (modes[FLAG_RUN] == 1) {
execute(0, -1);
}
}
/*=====================================================================*/
/*=====================================================================*/
/*---------------------------------------------------------------------
Interfacing With The Image
---------------------------------------------------------------------*/
/*---------------------------------------------------------------------
Stack push/pop is easy. I could avoid these, but it aids in keeping
the code readable, so it's worth the slight overhead.
---------------------------------------------------------------------*/
CELL stack_pop() {
sp--;
#ifndef NOCHECKS
if (sp < 0) {
printf("\nERROR (nga/stack_pop): Data stack underflow.\n");
exit(1);
}
#endif
return data[sp + 1];
}
void stack_push(CELL value) {
sp++;
#ifndef NOCHECKS
if (sp >= STACK_DEPTH) {
printf("\nERROR (nga/stack_push): Data stack overflow.\n");
exit(1);
}
#endif
data[sp] = value;
}
/*---------------------------------------------------------------------
Strings are next. RETRO uses C-style NULL terminated strings. So I
can easily inject or extract a string. Injection iterates over the
string, copying it into the image. This also takes care to ensure
that the NULL terminator is added.
---------------------------------------------------------------------*/
CELL string_inject(char *str, CELL buffer) {
CELL m, i;
if (!str) {
memory[buffer] = 0;
return 0;
}
m = strlen(str);
i = 0;
while (m > 0) {
memory[buffer + i] = (CELL)str[i];
memory[buffer + i + 1] = 0;
m--; i++;
}
return buffer;
}
/*---------------------------------------------------------------------
Extracting a string is similar, but I have to iterate over the VM
memory instead of a C string and copy the charaters into a buffer.
This uses a static buffer (`string_data`) as I prefer to avoid using
`malloc()`.
---------------------------------------------------------------------*/
char *string_extract(CELL at) {
CELL starting = at;
CELL i = 0;
while(memory[starting] && i < 8192)
string_data[i++] = (char)memory[starting++];
string_data[i] = 0;
return (char *)string_data;
}
/*---------------------------------------------------------------------
Continuing along, I now define functions to access the dictionary.
RETRO's dictionary is a linked list. Each entry is setup like:
0000 Link to previous entry (NULL if this is the root entry)
0001 Pointer to definition start
0002 Pointer to class handler
0003 Start of a NULL terminated string with the word name
First, functions to access each field. The offsets were defineed at
the start of the file.
---------------------------------------------------------------------*/
CELL d_link(CELL dt) {
return dt + D_OFFSET_LINK;
}
CELL d_xt(CELL dt) {
return dt + D_OFFSET_XT;
}
CELL d_class(CELL dt) {
return dt + D_OFFSET_CLASS;
}
CELL d_name(CELL dt) {
return dt + D_OFFSET_NAME;
}
/*---------------------------------------------------------------------
Next, a more complext word. This will walk through the entries to
find one with a name that matches the specified name. This is *slow*,
but works ok unless you have a really large dictionary. (I've not
run into issues with this in practice).
---------------------------------------------------------------------*/
CELL d_lookup(CELL Dictionary, char *name) {
CELL dt = 0;
CELL i = Dictionary;
char *dname;
while (memory[i] != 0 && i != 0) {
dname = string_extract(d_name(i));
if (strcmp(dname, name) == 0) {
dt = i;
i = 0;
} else {
i = memory[i];
}
}
return dt;
}
/*---------------------------------------------------------------------
My last dictionary related word returns the `xt` pointer for a word.
This is used to help keep various important bits up to date.
---------------------------------------------------------------------*/
CELL d_xt_for(char *Name, CELL Dictionary) {
return memory[d_xt(d_lookup(Dictionary, Name))];
}
/*---------------------------------------------------------------------
This interface tracks a few words and variables in the image. These
are:
Dictionary - the latest dictionary header
NotFound - called when a word is not found
interpret - the heart of the interpreter/compiler
I have to call this periodically, as the Dictionary will change as
new words are defined, and the user might write a new error handler
or interpreter.
---------------------------------------------------------------------*/
void update_rx() {
Dictionary = memory[2];
interpret = d_xt_for("interpret", Dictionary);
NotFound = d_xt_for("err:notfound", Dictionary);
Compiler = d_xt_for("Compiler", Compiler);
}
/*=====================================================================*/
#include "nga.c"
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