576 lines
13 KiB
C
576 lines
13 KiB
C
/* RETRO -------------------------------------------------------------
|
|
A personal, minimalistic forth
|
|
Copyright (c) 2016 - 2019 Charles Childers
|
|
|
|
This is the `repl`, a basic interactive interface for RETRO. It is
|
|
intended to be simple and very minimalistic, providing the minimal
|
|
I/O and additions needed to support a basic RETRO system. For a much
|
|
larger system, see `rre`.
|
|
|
|
I'll include commentary throughout the source, so read on.
|
|
---------------------------------------------------------------------*/
|
|
|
|
#include <sys/types.h>
|
|
#include "image.c"
|
|
|
|
int getchar(void);
|
|
int putchar(int c);
|
|
|
|
long stack_pop();
|
|
void stack_push(long value);
|
|
|
|
int remap(int c) {
|
|
int a = c;
|
|
#ifdef USE_DVORAK
|
|
switch (c) {
|
|
case 'q': a = '\''; break; case 'Q': a = '"'; break;
|
|
case 'w': a = ','; break; case 'W': a = '<'; break;
|
|
case 'e': a = '.'; break; case 'E': a = '>'; break;
|
|
case 'r': a = 'p'; break; case 'R': a = 'P'; break;
|
|
case 't': a = 'y'; break; case 'T': a = 'Y'; break;
|
|
case 'y': a = 'f'; break; case 'Y': a = 'F'; break;
|
|
case 'u': a = 'g'; break; case 'U': a = 'G'; break;
|
|
case 'i': a = 'c'; break; case 'I': a = 'C'; break;
|
|
case 'o': a = 'r'; break; case 'O': a = 'R'; break;
|
|
case 'p': a = 'l'; break; case 'P': a = 'L'; break;
|
|
case '[': a = '/'; break; case '{': a = '?'; break;
|
|
case ']': a = '='; break; case '}': a = '+'; break;
|
|
case 'a': a = 'a'; break; case 'A': a = 'A'; break;
|
|
case 's': a = 'o'; break; case 'S': a = 'O'; break;
|
|
case 'd': a = 'e'; break; case 'D': a = 'E'; break;
|
|
case 'f': a = 'u'; break; case 'F': a = 'U'; break;
|
|
case 'g': a = 'i'; break; case 'G': a = 'I'; break;
|
|
case 'h': a = 'd'; break; case 'H': a = 'D'; break;
|
|
case 'j': a = 'h'; break; case 'J': a = 'H'; break;
|
|
case 'k': a = 't'; break; case 'K': a = 'T'; break;
|
|
case 'l': a = 'n'; break; case 'L': a = 'N'; break;
|
|
case ';': a = 's'; break; case ':': a = 'S'; break;
|
|
case '\'': a = '-'; break; case '"': a = '_'; break;
|
|
case 'z': a = ';'; break; case 'Z': a = ':'; break;
|
|
case 'x': a = 'q'; break; case 'X': a = 'Q'; break;
|
|
case 'c': a = 'j'; break; case 'C': a = 'J'; break;
|
|
case 'v': a = 'k'; break; case 'V': a = 'K'; break;
|
|
case 'b': a = 'x'; break; case 'B': a = 'X'; break;
|
|
case 'n': a = 'b'; break; case 'N': a = 'B'; break;
|
|
case 'm': a = 'm'; break; case 'M': a = 'M'; break;
|
|
case ',': a = 'w'; break; case '<': a = 'W'; break;
|
|
case '.': a = 'v'; break; case '>': a = 'V'; break;
|
|
case '/': a = 'z'; break; case '?': a = 'Z'; break;
|
|
case '-': a = '['; break; case '_': a = '{'; break;
|
|
case '=': a = ']'; break; case '+': a = '}'; break;
|
|
}
|
|
#endif
|
|
return a;
|
|
}
|
|
|
|
int r_strlen(char *str) {
|
|
const char *s;
|
|
for (s = str; *s; ++s);
|
|
return(s - str);
|
|
}
|
|
|
|
int r_strcmp(const char *s1, const char *s2) {
|
|
while (*s1 == *s2++)
|
|
if (*s1++ == '\0')
|
|
return (0);
|
|
return (*(const unsigned char *)s1 - *(const unsigned char *)(s2 - 1));
|
|
}
|
|
|
|
#ifdef TARGET_X86
|
|
unsigned char inportb(unsigned int port)
|
|
{
|
|
unsigned char ret;
|
|
asm volatile ("inb %%dx,%%al":"=a" (ret):"d" (port));
|
|
return ret;
|
|
}
|
|
|
|
void outportb(unsigned int port,unsigned char value)
|
|
{
|
|
asm volatile ("outb %%al,%%dx": :"d" (port), "a" (value));
|
|
}
|
|
|
|
void store() {
|
|
long address = stack_pop();
|
|
long value = stack_pop();
|
|
*((int*)address) = value;
|
|
}
|
|
|
|
void fetch() {
|
|
stack_push(*((int*)stack_pop()));
|
|
}
|
|
|
|
void storeb() {
|
|
long address = stack_pop();
|
|
long value = stack_pop();
|
|
*((char *)address) = (char)value;
|
|
}
|
|
|
|
void fetchb() {
|
|
stack_push((long)*((char*)stack_pop()) & 0xFF);
|
|
}
|
|
|
|
static inline uint16_t inw(uint16_t port)
|
|
{
|
|
uint16_t ret;
|
|
asm volatile ( "inw %1, %0"
|
|
: "=a"(ret)
|
|
: "Nd"(port) );
|
|
return ret;
|
|
}
|
|
|
|
static inline void outw(uint16_t port, uint16_t val)
|
|
{
|
|
asm volatile ( "outw %0, %1" : : "a"(val), "Nd"(port) );
|
|
}
|
|
#endif
|
|
|
|
|
|
/*---------------------------------------------------------------------
|
|
Next we get into some things that relate to the Nga virtual machine
|
|
that RETRO runs on.
|
|
---------------------------------------------------------------------*/
|
|
|
|
#define CELL long /* Cell size (32 bit, signed integer */
|
|
#define IMAGE_SIZE 524288 * 8 /* Amount of RAM. 4MiB by default. */
|
|
#define ADDRESSES 1024 /* Depth of address stack */
|
|
#define STACK_DEPTH 128 /* Depth of data stack */
|
|
|
|
CELL sp, rp, ip; /* Data, address, 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 */
|
|
|
|
#ifdef TARGET_X86
|
|
#define NUM_DEVICES 3
|
|
#else
|
|
#define NUM_DEVICES 2
|
|
#endif
|
|
|
|
typedef void (*Handler)(void);
|
|
|
|
Handler IO_deviceHandlers[NUM_DEVICES + 1];
|
|
Handler IO_queryHandlers[NUM_DEVICES + 1];
|
|
|
|
|
|
/*---------------------------------------------------------------------
|
|
Function prototypes.
|
|
---------------------------------------------------------------------*/
|
|
|
|
void execute(int cell);
|
|
CELL ngaLoadImage(char *imageFile);
|
|
void ngaPrepare();
|
|
void ngaProcessOpcode(CELL opcode);
|
|
void ngaProcessPackedOpcodes(CELL opcode);
|
|
int ngaValidatePackedOpcodes(CELL opcode);
|
|
|
|
|
|
|
|
/*---------------------------------------------------------------------
|
|
Now to the fun stuff: interfacing with the virtual machine. There are
|
|
a things I like to have here:
|
|
|
|
- push a value to the stack
|
|
- pop a value off the stack
|
|
- extract a string from the image
|
|
- inject a string into the image.
|
|
- lookup dictionary headers and access dictionary fields
|
|
---------------------------------------------------------------------*/
|
|
|
|
|
|
/*---------------------------------------------------------------------
|
|
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--;
|
|
return data[sp + 1];
|
|
}
|
|
|
|
void stack_push(CELL value) {
|
|
sp++;
|
|
data[sp] = value;
|
|
}
|
|
|
|
|
|
/*---------------------------------------------------------------------
|
|
This is an implementation of the generic output device. It's set to
|
|
write output to the standard display.
|
|
---------------------------------------------------------------------*/
|
|
|
|
void generic_output() {
|
|
stack_pop();
|
|
}
|
|
|
|
void generic_output_query() {
|
|
stack_push(0);
|
|
stack_push(0);
|
|
}
|
|
|
|
|
|
#ifdef TARGET_X86
|
|
void portio() {
|
|
CELL p, v;
|
|
switch (stack_pop()) {
|
|
case 0: stack_push((CELL)inportb((unsigned int)stack_pop()));
|
|
break;
|
|
case 1: p = stack_pop();
|
|
v = stack_pop();
|
|
outportb((unsigned int)p, (unsigned char)v);
|
|
break;
|
|
case 2: store();
|
|
break;
|
|
case 3: fetch();
|
|
break;
|
|
case 4: storeb();
|
|
break;
|
|
case 5: fetchb();
|
|
break;
|
|
case 6: stack_push((CELL)inw((uint16_t)stack_pop()));
|
|
break;
|
|
case 7: p = stack_pop();
|
|
v = stack_pop();
|
|
outw((uint16_t)p, (uint16_t)v);
|
|
break;
|
|
}
|
|
}
|
|
|
|
void portio_query() {
|
|
stack_push(0);
|
|
stack_push(2000);
|
|
}
|
|
#endif
|
|
|
|
void generic_input() {
|
|
stack_push(remap(getchar()));
|
|
if (TOS == 127) TOS = 8;
|
|
}
|
|
|
|
void generic_input_query() {
|
|
stack_push(0);
|
|
stack_push(1);
|
|
}
|
|
|
|
/*---------------------------------------------------------------------
|
|
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.
|
|
|
|
Nga uses packed instruction bundles, with up to four instructions per
|
|
bundle. Since RETRO requires an additional instruction to handle
|
|
displaying a character, I define the handler for that here.
|
|
|
|
This will also exit if the address stack depth is zero (meaning that
|
|
the word being run, and it's dependencies) are finished.
|
|
---------------------------------------------------------------------*/
|
|
|
|
void execute(int cell) {
|
|
CELL opcode;
|
|
rp = 1;
|
|
ip = cell;
|
|
while (ip < IMAGE_SIZE) {
|
|
opcode = memory[ip];
|
|
if (ngaValidatePackedOpcodes(opcode) != 0) {
|
|
ngaProcessPackedOpcodes(opcode);
|
|
} else {
|
|
while(1);
|
|
}
|
|
ip++;
|
|
if (rp == 0)
|
|
ip = IMAGE_SIZE;
|
|
}
|
|
}
|
|
|
|
|
|
/*---------------------------------------------------------------------
|
|
The `main()` routine. This sets up the Nga VM, loads the image, and
|
|
enters a loop.
|
|
|
|
The loop:
|
|
|
|
- reads input
|
|
- otherwise, pass to `evaluate()` to run
|
|
---------------------------------------------------------------------*/
|
|
|
|
int main(int argc, char **argv) {
|
|
IO_deviceHandlers[0] = generic_output;
|
|
IO_queryHandlers[0] = generic_output_query;
|
|
IO_deviceHandlers[1] = generic_input;
|
|
IO_queryHandlers[1] = generic_input_query;
|
|
#ifdef TARGET_X86
|
|
IO_deviceHandlers[2] = portio;
|
|
IO_queryHandlers[2] = portio_query;
|
|
#endif
|
|
while (1) {
|
|
ngaPrepare();
|
|
for (CELL i = 0; i < ngaImageCells; i++)
|
|
memory[i] = ngaImage[i];
|
|
execute(0);
|
|
}
|
|
}
|
|
|
|
|
|
/* Nga ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
Copyright (c) 2008 - 2019, Charles Childers
|
|
Copyright (c) 2009 - 2010, Luke Parrish
|
|
Copyright (c) 2010, Marc Simpson
|
|
Copyright (c) 2010, Jay Skeer
|
|
Copyright (c) 2011, Kenneth Keating
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
|
|
|
|
enum vm_opcode {
|
|
VM_NOP, VM_LIT, VM_DUP, VM_DROP, VM_SWAP, VM_PUSH, VM_POP,
|
|
VM_JUMP, VM_CALL, VM_CCALL, VM_RETURN, VM_EQ, VM_NEQ, VM_LT,
|
|
VM_GT, VM_FETCH, VM_STORE, VM_ADD, VM_SUB, VM_MUL, VM_DIVMOD,
|
|
VM_AND, VM_OR, VM_XOR, VM_SHIFT, VM_ZRET, VM_END, VM_IE,
|
|
VM_IQ, VM_II
|
|
};
|
|
#define NUM_OPS VM_II + 1
|
|
|
|
#ifndef NUM_DEVICES
|
|
#define NUM_DEVICES 0
|
|
#endif
|
|
|
|
CELL ngaLoadImage(char *imageFile) {
|
|
CELL i;
|
|
for (i = 0; i < ngaImageCells; i++)
|
|
memory[i] = ngaImage[i];
|
|
return i;
|
|
}
|
|
|
|
void ngaPrepare() {
|
|
ip = sp = rp = 0;
|
|
for (ip = 0; ip < IMAGE_SIZE; ip++)
|
|
memory[ip] = VM_NOP;
|
|
for (ip = 0; ip < STACK_DEPTH; ip++)
|
|
data[ip] = 0;
|
|
for (ip = 0; ip < ADDRESSES; ip++)
|
|
address[ip] = 0;
|
|
}
|
|
|
|
void inst_nop() {
|
|
}
|
|
|
|
void inst_lit() {
|
|
sp++;
|
|
ip++;
|
|
TOS = memory[ip];
|
|
}
|
|
|
|
void inst_dup() {
|
|
sp++;
|
|
data[sp] = NOS;
|
|
}
|
|
|
|
void inst_drop() {
|
|
data[sp] = 0;
|
|
if (--sp < 0)
|
|
ip = IMAGE_SIZE;
|
|
}
|
|
|
|
void inst_swap() {
|
|
CELL a;
|
|
a = TOS;
|
|
TOS = NOS;
|
|
NOS = a;
|
|
}
|
|
|
|
void inst_push() {
|
|
rp++;
|
|
TORS = TOS;
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_pop() {
|
|
sp++;
|
|
TOS = TORS;
|
|
rp--;
|
|
}
|
|
|
|
void inst_jump() {
|
|
ip = TOS - 1;
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_call() {
|
|
rp++;
|
|
TORS = ip;
|
|
ip = TOS - 1;
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_ccall() {
|
|
CELL a, b;
|
|
a = TOS; inst_drop(); /* False */
|
|
b = TOS; inst_drop(); /* Flag */
|
|
if (b != 0) {
|
|
rp++;
|
|
TORS = ip;
|
|
ip = a - 1;
|
|
}
|
|
}
|
|
|
|
void inst_return() {
|
|
ip = TORS;
|
|
rp--;
|
|
}
|
|
|
|
void inst_eq() {
|
|
NOS = (NOS == TOS) ? -1 : 0;
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_neq() {
|
|
NOS = (NOS != TOS) ? -1 : 0;
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_lt() {
|
|
NOS = (NOS < TOS) ? -1 : 0;
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_gt() {
|
|
NOS = (NOS > TOS) ? -1 : 0;
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_fetch() {
|
|
switch (TOS) {
|
|
case -1: TOS = sp - 1; break;
|
|
case -2: TOS = rp; break;
|
|
case -3: TOS = IMAGE_SIZE; break;
|
|
default: TOS = memory[TOS]; break;
|
|
}
|
|
}
|
|
|
|
void inst_store() {
|
|
if (TOS <= IMAGE_SIZE && TOS >= 0) {
|
|
memory[TOS] = NOS;
|
|
inst_drop();
|
|
inst_drop();
|
|
} else {
|
|
ip = IMAGE_SIZE;
|
|
}
|
|
}
|
|
|
|
void inst_add() {
|
|
NOS += TOS;
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_sub() {
|
|
NOS -= TOS;
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_mul() {
|
|
NOS *= TOS;
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_divmod() {
|
|
CELL a, b;
|
|
a = TOS;
|
|
b = NOS;
|
|
TOS = b / a;
|
|
NOS = b % a;
|
|
}
|
|
|
|
void inst_and() {
|
|
NOS = TOS & NOS;
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_or() {
|
|
NOS = TOS | NOS;
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_xor() {
|
|
NOS = TOS ^ NOS;
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_shift() {
|
|
CELL y = TOS;
|
|
CELL x = NOS;
|
|
if (TOS < 0)
|
|
NOS = NOS << (TOS * -1);
|
|
else {
|
|
if (x < 0 && y > 0)
|
|
NOS = x >> y | ~(~0U >> y);
|
|
else
|
|
NOS = x >> y;
|
|
}
|
|
inst_drop();
|
|
}
|
|
|
|
void inst_zret() {
|
|
if (TOS == 0) {
|
|
inst_drop();
|
|
ip = TORS;
|
|
rp--;
|
|
}
|
|
}
|
|
|
|
void inst_end() {
|
|
ip = IMAGE_SIZE;
|
|
}
|
|
|
|
void inst_ie() {
|
|
sp++;
|
|
TOS = NUM_DEVICES;
|
|
}
|
|
|
|
void inst_iq() {
|
|
CELL Device = TOS;
|
|
inst_drop();
|
|
IO_queryHandlers[Device]();
|
|
}
|
|
|
|
void inst_ii() {
|
|
CELL Device = TOS;
|
|
inst_drop();
|
|
IO_deviceHandlers[Device]();
|
|
}
|
|
|
|
Handler instructions[NUM_OPS] = {
|
|
inst_nop, inst_lit, inst_dup, inst_drop, inst_swap, inst_push, inst_pop,
|
|
inst_jump, inst_call, inst_ccall, inst_return, inst_eq, inst_neq, inst_lt,
|
|
inst_gt, inst_fetch, inst_store, inst_add, inst_sub, inst_mul, inst_divmod,
|
|
inst_and, inst_or, inst_xor, inst_shift, inst_zret, inst_end, inst_ie,
|
|
inst_iq, inst_ii
|
|
};
|
|
|
|
void ngaProcessOpcode(CELL opcode) {
|
|
if (opcode != 0)
|
|
instructions[opcode]();
|
|
}
|
|
|
|
int ngaValidatePackedOpcodes(CELL opcode) {
|
|
CELL raw = opcode;
|
|
CELL current;
|
|
int valid = -1;
|
|
int i;
|
|
for (i = 0; i < 4; i++) {
|
|
current = raw & 0xFF;
|
|
if (!(current >= 0 && current <= 29))
|
|
valid = 0;
|
|
raw = raw >> 8;
|
|
}
|
|
return valid;
|
|
}
|
|
|
|
void ngaProcessPackedOpcodes(CELL opcode) {
|
|
CELL raw = opcode;
|
|
int i;
|
|
for (i = 0; i < 4; i++) {
|
|
ngaProcessOpcode(raw & 0xFF);
|
|
raw = raw >> 8;
|
|
}
|
|
}
|