/* planck - 
 * Copyright (C) 2021 nineties
 */
#ifndef INCLUDE_DEFS
#define INCLUDE_DEFS

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

typedef uintptr_t cell;
typedef void (**cfa)();

#define CELL            sizeof(cell)
#define STACK_SIZE      1024
#define RSTACK_SIZE     1024
#define MEMORY_SIZE     0x100000

typedef struct builtin {
    struct builtin *prev;
    char len;
    char name;
    char padding[CELL-2];
    void (*fun)();
} builtin;

static cell stack[STACK_SIZE];
static cell rstack[RSTACK_SIZE];
static cell *dsp = stack + STACK_SIZE;
static cell *rsp = rstack + RSTACK_SIZE;

static cell memory[MEMORY_SIZE];
static builtin *latest = 0;
static cell *here = memory;
static cell *pc = NULL;
static cfa  ip = NULL;

#define next()     (*(ip = (cfa)(*pc++)))()

static void push(cell v)  { *(--dsp) = v; }
static cell pop(void)     { return *dsp++; }
static void rpush(cell v) { *(--rsp) = v; }
static cell rpop(void)    { return *rsp++; }

static void docol(void) {
    rpush((cell) pc);
    pc = (cell*)ip + 1;
    next();
}

static cfa find(char c) {
    for (builtin *it = latest; it; it = it->prev)
        if (it->len == 1 && it->name == c)
            return &it->fun;
    return 0;
}

#define defcode(name, label) \
static void label()
#include "planck.c"
#undef defcode

int main(void) {
#define defcode(c, label) \
    memcpy(here, &(builtin){ latest, 1, c, {0}, label }, 3*CELL); \
    latest = (builtin*)here; \
    here += 3; \
    if (0) // skip function body
#include "planck.c"

    cfa start = (cfa) here;
    *here++ = (cell) find('k');
    *here++ = (cell) find('f');
    *here++ = (cell) find('x');
    *here++ = (cell) find('j');
    *here++ = (cell) -4 * CELL;
    pc = (cell*) start;
    next();
    return 0;
}
#else
defcode('Q', quit) { exit(0); }
defcode('C', cell_) { push(CELL); next(); }
defcode('h', here_) { push((cell)&here); next(); }
defcode('l', latest_) { push((cell)&latest); next(); }
defcode('i', docol_) { push((cell)docol); next(); }
defcode('e', exit_) { pc = (cell*)rpop(); next(); }
defcode('@', fetch) { cell *p = (cell*)pop(); push(*p); next(); }
defcode('!', store) { cell *p = (cell*)pop(); *p = pop(); next(); }
defcode('?', cfetch) { char *p = (char*)pop(); push(*p); next(); }
defcode('$', cstore) { char *p = (char*)pop(); *p = pop(); next(); }
defcode('d', dfetch) { push((cell)dsp); next(); }
defcode('D', dstore) { dsp = (cell*) pop(); next(); }
defcode('r', rfetch) { push((cell)rsp); next(); }
defcode('R', rstore) { rsp = (cell*) pop(); next(); }
defcode('j', jump) { pc += (int)*pc/CELL; next(); }
defcode('J', jump0) { pc += (int)(pop()?1:*pc/CELL); next(); }
defcode('L', lit) { push(*pc++); next(); }
defcode('S', litstring) {
    int len = *pc++;
    push((cell) pc);
    push(len);
    pc += (len + CELL - 1)/CELL;
}
defcode('k', key) { 
    int c = getchar();
    if (c <= 0)
        exit(0);
    push(c);
    next();
}
defcode('t', type) { putchar(pop()); next(); }
defcode('x', exec) { (*(ip = (cfa) pop()))(); }
defcode('f', find_) { push((cell) find(pop())); next(); }
#define defbinary(c, label, op, ty) \
defcode(c, label) { \
    ty b = (ty) pop(); \
    *dsp = (cell)((ty) *dsp op b); \
    next(); \
}
defbinary('+', add, +, intptr_t)
defbinary('-', sub, -, intptr_t)
defbinary('*', mul, *, intptr_t)
defbinary('/', div_, /, intptr_t)
defbinary('%', mod, %, intptr_t)
defbinary('&', and, &, uintptr_t)
defbinary('|', or, |, uintptr_t)
defbinary('^', xor, ^, uintptr_t)
defbinary('<', lt, <, intptr_t)
defbinary('=', eq, ==, intptr_t)

#endif