shithub: femtolisp

ref: 7c57c0393fd368602203e8478817ab03861fc2c5
dir: /flisp.c/

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/*
  femtoLisp

  by Jeff Bezanson (C) 2009
  Distributed under the BSD License
*/

#include "llt.h"
#include "flisp.h"

typedef struct Builtin Builtin;

struct Builtin {
    char *name;
    int  nargs;
};

#define ANYARGS -10000

#include "opcodes.h"

int isbuiltin(value_t x)
{
    int i = uintval(x);
    return tag(x) == TAG_FUNCTION && i < nelem(builtins) && builtins[i].name != nil;
}

static uint32_t N_STACK;
static value_t *Stack;
static uint32_t SP = 0;
static uint32_t curr_frame = 0;
static char *curr_fname = nil;
#define PUSH(v) (Stack[SP++] = (v))
#define POP()   (Stack[--SP])
#define POPN(n) (SP-=(n))

#define N_GC_HANDLES 1024
static value_t *GCHandleStack[N_GC_HANDLES];
static uint32_t N_GCHND = 0;

value_t FL_NIL, FL_T, FL_F, FL_EOF, QUOTE;
value_t IOError, ParseError, TypeError, ArgError, MemoryError;
value_t DivideError, BoundsError, Error, KeyError, EnumerationError;
static value_t UnboundError;
value_t printwidthsym, printreadablysym, printprettysym, printlengthsym;
value_t printlevelsym, builtins_table_sym;

static value_t NIL, LAMBDA, IF, TRYCATCH;
static value_t BACKQUOTE, COMMA, COMMAAT, COMMADOT, FUNCTION;

static value_t pairsym, symbolsym, fixnumsym, vectorsym, builtinsym, vu8sym;
static value_t definesym, defmacrosym, forsym, setqsym;
static value_t tsym, Tsym, fsym, Fsym, booleansym, nullsym, evalsym, fnsym;
// for reading characters
static value_t nulsym, alarmsym, backspacesym, tabsym, linefeedsym, newlinesym;
static value_t vtabsym, pagesym, returnsym, escsym, spacesym, deletesym;

static value_t apply_cl(uint32_t nargs);
static value_t *alloc_words(int n);
static value_t relocate(value_t v);

static fl_readstate_t *readstate = nil;

static void free_readstate(fl_readstate_t *rs)
{
    htable_free(&rs->backrefs);
    htable_free(&rs->gensyms);
}

static uint8_t *fromspace;
static uint8_t *tospace;
static uint8_t *curheap;
static uint8_t *lim;
static uint32_t heapsize;//bytes
static uint32_t *consflags;

// error utilities ------------------------------------------------------------

// saved execution state for an unwind target
fl_exception_context_t *fl_ctx = nil;
uint32_t fl_throwing_frame=0;  // active frame when exception was thrown
value_t fl_lasterror;

#define FL_TRY \
  fl_exception_context_t _ctx; int l__tr, l__ca; \
  _ctx.sp=SP; _ctx.frame=curr_frame; _ctx.rdst=readstate; _ctx.prev=fl_ctx; \
  _ctx.ngchnd = N_GCHND; fl_ctx = &_ctx;                                    \
  if (!setjmp(_ctx.buf)) \
    for (l__tr=1; l__tr; l__tr=0, (void)(fl_ctx=fl_ctx->prev))

#define FL_CATCH_INC \
  l__ca=0,fl_lasterror=FL_NIL,fl_throwing_frame=0,SP=_ctx.sp,curr_frame=_ctx.frame

#define FL_CATCH \
  else \
    for(l__ca=1; l__ca;FL_CATCH_INC)

#define FL_CATCH_NO_INC \
  else \
    for(l__ca=1; l__ca;)

void fl_savestate(fl_exception_context_t *_ctx)
{
    _ctx->sp = SP;
    _ctx->frame = curr_frame;
    _ctx->rdst = readstate;
    _ctx->prev = fl_ctx;
    _ctx->ngchnd = N_GCHND;
}

void fl_restorestate(fl_exception_context_t *_ctx)
{
    fl_lasterror = FL_NIL;
    fl_throwing_frame = 0;
    SP = _ctx->sp;
    curr_frame = _ctx->frame;
}

_Noreturn void fl_raise(value_t e)
{
    fl_lasterror = e;
    // unwind read state
    while (readstate != fl_ctx->rdst) {
        free_readstate(readstate);
        readstate = readstate->prev;
    }
    if (fl_throwing_frame == 0)
        fl_throwing_frame = curr_frame;
    N_GCHND = fl_ctx->ngchnd;
    fl_exception_context_t *thisctx = fl_ctx;
    if (fl_ctx->prev)   // don't throw past toplevel
        fl_ctx = fl_ctx->prev;
    longjmp(thisctx->buf, 1);
}

static value_t make_error_msg(char *format, va_list args)
{
    char msgbuf[512], *s;
    int n;
    if (curr_fname != nil) {
        n = snprintf(msgbuf, sizeof(msgbuf), "%s: ", curr_fname);
        curr_fname = nil;
    } else {
        n = 0;
    }
    s = msgbuf + n;
    n = sizeof(msgbuf) - n;
    vsnprintf(s, n, format, args);
    return string_from_cstr(msgbuf);
}

_Noreturn void lerrorf(value_t e, char *format, ...)
{
    va_list args;
    PUSH(e);
    va_start(args, format);
    value_t msg = make_error_msg(format, args);
    va_end(args);

    e = POP();
    fl_raise(fl_list2(e, msg));
}

_Noreturn void type_error(char *expected, value_t got)
{
    fl_raise(fl_listn(4, TypeError, symbol(curr_fname), symbol(expected), got));
}

_Noreturn void bounds_error(value_t arr, value_t ind)
{
    fl_raise(fl_listn(4, BoundsError, symbol(curr_fname), arr, ind));
}

_Noreturn void unbound_error(value_t sym)
{
    fl_raise(fl_listn(3, UnboundError, symbol(curr_fname), sym));
}

// safe cast operators --------------------------------------------------------

#define isstring fl_isstring
#define SAFECAST_OP(type,ctype,cnvt)                             \
ctype to##type(value_t v)                                        \
{                                                                \
    if (is##type(v))                                             \
        return (ctype)cnvt(v);                                   \
    type_error(#type, v);                                        \
}
SAFECAST_OP(cons,  cons_t*,  ptr)
SAFECAST_OP(symbol,symbol_t*,ptr)
SAFECAST_OP(fixnum,fixnum_t, numval)
SAFECAST_OP(cvalue,cvalue_t*,ptr)
SAFECAST_OP(string,char*,    cvalue_data)
#undef isstring

// symbol table ---------------------------------------------------------------

symbol_t *symtab = nil;

int fl_is_keyword_name(char *str, size_t len)
{
    return ((str[0] == ':' || str[len-1] == ':') && str[1] != '\0');
}

static symbol_t *mk_symbol(char *str)
{
    symbol_t *sym;
    size_t len = strlen(str);

    sym = calloc(1, sizeof(*sym)-sizeof(void*) + len + 1);
    assert(((uintptr_t)sym & 0x7) == 0); // make sure malloc aligns 8
    sym->numtype = NONNUMERIC;
    if (fl_is_keyword_name(str, len)) {
        value_t s = tagptr(sym, TAG_SYM);
        setc(s, s);
        sym->flags |= FLAG_KEYWORD;
    }
    else {
        sym->binding = UNBOUND;
    }
    sym->hash = memhash32(str, len)^0xAAAAAAAA;
    memmove(sym->name, str, len+1);
    return sym;
}

static symbol_t **symtab_lookup(symbol_t **ptree, char *str)
{
    int x;

    while(*ptree != nil) {
        x = strcmp(str, (*ptree)->name);
        if (x == 0)
            return ptree;
        if (x < 0)
            ptree = &(*ptree)->left;
        else
            ptree = &(*ptree)->right;
    }
    return ptree;
}

value_t symbol(char *str)
{
    symbol_t **pnode;

    pnode = symtab_lookup(&symtab, str);
    if (*pnode == nil)
        *pnode = mk_symbol(str);
    return tagptr(*pnode, TAG_SYM);
}

static uint32_t _gensym_ctr=0;
// two static buffers for gensym printing so there can be two
// gensym names available at a time, mostly for compare()
static char gsname[2][16];
static int gsnameno=0;
BUILTIN("gensym", gensym)
{
    argcount(nargs, 0);
    USED(args);
    gensym_t *gs = (gensym_t*)alloc_words(sizeof(gensym_t)/sizeof(void*));
    gs->id = _gensym_ctr++;
    gs->binding = UNBOUND;
    gs->isconst = 0;
    gs->type = nil;
    return tagptr(gs, TAG_SYM);
}

value_t gensym(void)
{
    return fn_builtin_gensym(nil, 0);
}

BUILTIN("gensym?", gensymp)
{
    argcount(nargs, 1);
    return isgensym(args[0]) ? FL_T : FL_F;
}

char *symbol_name(value_t v)
{
    if (ismanaged(v)) {
        gensym_t *gs = (gensym_t*)ptr(v);
        gsnameno = 1-gsnameno;
        char *n = uint2str(gsname[gsnameno]+1, sizeof(gsname[0])-1, gs->id, 10);
        *(--n) = 'g';
        return n;
    }
    return ((symbol_t*)ptr(v))->name;
}

// conses ---------------------------------------------------------------------

void gc(int mustgrow);

static value_t mk_cons(void)
{
    cons_t *c;

    if (__unlikely(curheap > lim))
        gc(0);
    c = (cons_t*)curheap;
    curheap += sizeof(cons_t);
    return tagptr(c, TAG_CONS);
}

static value_t *alloc_words(int n)
{
    value_t *first;

    assert(n > 0);
    n = LLT_ALIGN(n, 2);   // only allocate multiples of 2 words
    if (__unlikely((value_t*)curheap > ((value_t*)lim)+2-n)) {
        gc(0);
        while ((value_t*)curheap > ((value_t*)lim)+2-n) {
            gc(1);
        }
    }
    first = (value_t*)curheap;
    curheap += (n*sizeof(value_t));
    return first;
}

// allocate n consecutive conses
#define cons_reserve(n) tagptr(alloc_words((n)*2), TAG_CONS)

#define cons_index(c)  (((cons_t*)ptr(c))-((cons_t*)fromspace))
#define ismarked(c)    bitvector_get(consflags, cons_index(c))
#define mark_cons(c)   bitvector_set(consflags, cons_index(c), 1)
#define unmark_cons(c) bitvector_set(consflags, cons_index(c), 0)

static value_t the_empty_vector;

value_t alloc_vector(size_t n, int init)
{
    if (n == 0) return the_empty_vector;
    value_t *c = alloc_words(n+1);
    value_t v = tagptr(c, TAG_VECTOR);
    vector_setsize(v, n);
    if (init) {
        unsigned int i;
        for(i=0; i < n; i++)
            vector_elt(v, i) = FL_UNSPECIFIED;
    }
    return v;
}

// cvalues --------------------------------------------------------------------

#include "cvalues.c"
#include "types.c"

// print ----------------------------------------------------------------------

static int isnumtok(char *tok, value_t *pval);
static inline int symchar(char c);

#include "print.c"

// collector ------------------------------------------------------------------

void fl_gc_handle(value_t *pv)
{
    if (N_GCHND >= N_GC_HANDLES)
        lerrorf(MemoryError, "out of gc handles");
    GCHandleStack[N_GCHND++] = pv;
}

void fl_free_gc_handles(uint32_t n)
{
    assert(N_GCHND >= n);
    N_GCHND -= n;
}

static value_t relocate(value_t v)
{
    value_t a, d, nc, first, *pcdr;
    uintptr_t t = tag(v);

    if (t == TAG_CONS) {
        // iterative implementation allows arbitrarily long cons chains
        pcdr = &first;
        do {
            if ((a=car_(v)) == TAG_FWD) {
                *pcdr = cdr_(v);
                return first;
            }
            *pcdr = nc = tagptr((cons_t*)curheap, TAG_CONS);
            curheap += sizeof(cons_t);
            d = cdr_(v);
            car_(v) = TAG_FWD; cdr_(v) = nc;
            car_(nc) = relocate(a);
            pcdr = &cdr_(nc);
            v = d;
        } while (iscons(v));
        *pcdr = (d==NIL) ? NIL : relocate(d);
        return first;
    }

    if ((t&3) == 0) return v;
    if (!ismanaged(v)) return v;
    if (isforwarded(v)) return forwardloc(v);

    if (t == TAG_VECTOR) {
        // N.B.: 0-length vectors secretly have space for a first element
        size_t i, sz = vector_size(v);
        if (vector_elt(v,-1) & 0x1) {
            // grown vector
            nc = relocate(vector_elt(v,0));
            forward(v, nc);
        }
        else {
            nc = tagptr(alloc_words(sz+1), TAG_VECTOR);
            vector_setsize(nc, sz);
            a = vector_elt(v,0);
            forward(v, nc);
            if (sz > 0) {
                vector_elt(nc,0) = relocate(a);
                for(i=1; i < sz; i++)
                    vector_elt(nc,i) = relocate(vector_elt(v,i));
            }
        }
        return nc;
    }
    else if (t == TAG_CPRIM) {
        cprim_t *pcp = (cprim_t*)ptr(v);
        size_t nw = CPRIM_NWORDS-1+NWORDS(cp_class(pcp)->size);
        cprim_t *ncp = (cprim_t*)alloc_words(nw);
        while (nw--)
            ((value_t*)ncp)[nw] = ((value_t*)pcp)[nw];
        nc = tagptr(ncp, TAG_CPRIM);
        forward(v, nc);
        return nc;
    }
    else if (t == TAG_CVALUE) {
        return cvalue_relocate(v);
    }
    else if (t == TAG_FUNCTION) {
        function_t *fn = (function_t*)ptr(v);
        function_t *nfn = (function_t*)alloc_words(4);
        nfn->bcode = fn->bcode;
        nfn->vals = fn->vals;
        nc = tagptr(nfn, TAG_FUNCTION);
        forward(v, nc);
        nfn->env = relocate(fn->env);
        nfn->vals = relocate(nfn->vals);
        nfn->bcode = relocate(nfn->bcode);
        assert(!ismanaged(fn->name));
        nfn->name = fn->name;
        return nc;
    }
    else if (t == TAG_SYM) {
        gensym_t *gs = (gensym_t*)ptr(v);
        gensym_t *ng = (gensym_t*)alloc_words(sizeof(gensym_t)/sizeof(void*));
        ng->id = gs->id;
        ng->binding = gs->binding;
        ng->isconst = 0;
        nc = tagptr(ng, TAG_SYM);
        forward(v, nc);
        if (ng->binding != UNBOUND)
            ng->binding = relocate(ng->binding);
        return nc;
    }
    return v;
}

value_t relocate_lispvalue(value_t v)
{
    return relocate(v);
}

static void trace_globals(symbol_t *root)
{
    while (root != nil) {
        if (root->binding != UNBOUND)
            root->binding = relocate(root->binding);
        trace_globals(root->left);
        root = root->right;
    }
}

static value_t memory_exception_value;

void gc(int mustgrow)
{
    static int grew = 0;
    void *temp;
    uint32_t i, f, top;
    fl_readstate_t *rs;

    curheap = tospace;
    if (grew)
        lim = curheap+heapsize*2-sizeof(cons_t);
    else
        lim = curheap+heapsize-sizeof(cons_t);

    if (fl_throwing_frame > curr_frame) {
        top = fl_throwing_frame - 4;
        f = Stack[fl_throwing_frame-4];
    }
    else {
        top = SP;
        f = curr_frame;
    }
    while (1) {
        for (i=f; i < top; i++)
            Stack[i] = relocate(Stack[i]);
        if (f == 0) break;
        top = f - 4;
        f = Stack[f-4];
    }
    for (i=0; i < N_GCHND; i++)
        *GCHandleStack[i] = relocate(*GCHandleStack[i]);
    trace_globals(symtab);
    relocate_typetable();
    rs = readstate;
    while (rs) {
        value_t ent;
        for(i=0; i < rs->backrefs.size; i++) {
            ent = (value_t)rs->backrefs.table[i];
            if (ent != (value_t)HT_NOTFOUND)
                rs->backrefs.table[i] = (void*)relocate(ent);
        }
        for(i=0; i < rs->gensyms.size; i++) {
            ent = (value_t)rs->gensyms.table[i];
            if (ent != (value_t)HT_NOTFOUND)
                rs->gensyms.table[i] = (void*)relocate(ent);
        }
        rs->source = relocate(rs->source);
        rs = rs->prev;
    }
    fl_lasterror = relocate(fl_lasterror);
    memory_exception_value = relocate(memory_exception_value);
    the_empty_vector = relocate(the_empty_vector);

    sweep_finalizers();

#ifdef VERBOSEGC
    printf("GC: found %d/%d live conses\n",
           (curheap-tospace)/sizeof(cons_t), heapsize/sizeof(cons_t));
#endif
    temp = tospace;
    tospace = fromspace;
    fromspace = temp;

    // if we're using > 80% of the space, resize tospace so we have
    // more space to fill next time. if we grew tospace last time,
    // grow the other half of the heap this time to catch up.
    if (grew || ((lim-curheap) < (int)(heapsize/5)) || mustgrow) {
        temp = LLT_REALLOC(tospace, heapsize*2);
        if (temp == nil)
            fl_raise(memory_exception_value);
        tospace = temp;
        if (grew) {
            heapsize*=2;
            temp = bitvector_resize(consflags, 0, heapsize/sizeof(cons_t), 1);
            if (temp == nil)
                fl_raise(memory_exception_value);
            consflags = (uint32_t*)temp;
        }
        grew = !grew;
    }
    if (curheap > lim)  // all data was live
        gc(0);
}

static void grow_stack(void)
{
    size_t newsz = N_STACK + (N_STACK>>1);
    value_t *ns = realloc(Stack, newsz*sizeof(value_t));
    if (ns == nil)
        lerrorf(MemoryError, "stack overflow");
    Stack = ns;
    N_STACK = newsz;
}

// utils ----------------------------------------------------------------------

static char *cvalue_name(value_t v)
{
    cvalue_t *cv = (cvalue_t*)ptr(v);
    static char name[64];
    value_t label;

    void *data = cptr(v);
    void *fptr = *(void**)data;
    label = (value_t)ptrhash_get(&reverse_dlsym_lookup_table, cv);
    if (label == (value_t)HT_NOTFOUND)
        snprintf(name, sizeof(name), "#<builtin @%p>", fptr);
    else
        snprintf(name, sizeof(name), "#fn(%s)", symbol_name(label));
    return name;
}


// apply function with n args on the stack
static value_t _applyn(uint32_t n)
{
    value_t f = Stack[SP-n-1];
    uint32_t saveSP = SP;
    value_t v;
    if (iscbuiltin(f)) {
        curr_fname = cvalue_name(f);
        v = ((builtin_t*)ptr(f))[3](&Stack[SP-n], n);
    }
    else if (isfunction(f)) {
        v = apply_cl(n);
    }
    else if (isbuiltin(f)) {
        value_t tab = symbol_value(builtins_table_sym);
        if (ptr(tab) == nil)
            unbound_error(tab);
        Stack[SP-n-1] = vector_elt(tab, uintval(f));
        curr_fname = builtins[uintval(f)].name;
        v = apply_cl(n);
    }
    else {
        type_error("function", f);
    }
    SP = saveSP;
    return v;
}

value_t fl_apply(value_t f, value_t l)
{
    value_t v = l;
    uint32_t n = SP;

    PUSH(f);
    while (iscons(v)) {
        if (SP >= N_STACK)
            grow_stack();
        PUSH(car_(v));
        v = cdr_(v);
    }
    n = SP - n - 1;
    v = _applyn(n);
    POPN(n+1);
    return v;
}

value_t fl_applyn(uint32_t n, value_t f, ...)
{
    va_list ap;
    va_start(ap, f);
    size_t i;

    PUSH(f);
    while (SP+n > N_STACK)
        grow_stack();
    for(i=0; i < n; i++) {
        value_t a = va_arg(ap, value_t);
        PUSH(a);
    }
    value_t v = _applyn(n);
    POPN(n+1);
    va_end(ap);
    return v;
}

value_t fl_listn(size_t n, ...)
{
    va_list ap;
    va_start(ap, n);
    uint32_t si = SP;
    size_t i;

    while (SP+n > N_STACK)
        grow_stack();
    for(i=0; i < n; i++) {
        value_t a = va_arg(ap, value_t);
        PUSH(a);
    }
    cons_t *c = (cons_t*)alloc_words(n*2);
    cons_t *l = c;
    for(i=0; i < n; i++) {
        c->car = Stack[si++];
        c->cdr = tagptr(c+1, TAG_CONS);
        c++;
    }
    (c-1)->cdr = NIL;

    POPN(n);
    va_end(ap);
    return tagptr(l, TAG_CONS);
}

value_t fl_list2(value_t a, value_t b)
{
    PUSH(a);
    PUSH(b);
    cons_t *c = (cons_t*)alloc_words(4);
    b = POP();
    a = POP();
    c[0].car = a;
    c[0].cdr = tagptr(c+1, TAG_CONS);
    c[1].car = b;
    c[1].cdr = NIL;
    return tagptr(c, TAG_CONS);
}

value_t fl_cons(value_t a, value_t b)
{
    PUSH(a);
    PUSH(b);
    value_t c = mk_cons();
    cdr_(c) = POP();
    car_(c) = POP();
    return c;
}

int fl_isnumber(value_t v)
{
    if (isfixnum(v)) return 1;
    if (iscprim(v)) {
        cprim_t *c = (cprim_t*)ptr(v);
        return c->type != wchartype;
    }
    return 0;
}

// read -----------------------------------------------------------------------

#include "read.c"

// equal ----------------------------------------------------------------------

#include "equal.c"

// eval -----------------------------------------------------------------------

static value_t list(value_t *args, uint32_t nargs, int star)
{
    cons_t *c;
    uint32_t i;
    value_t v;
    v = cons_reserve(nargs);
    c = (cons_t*)ptr(v);
    for(i=0; i < nargs; i++) {
        c->car = args[i];
        c->cdr = tagptr(c+1, TAG_CONS);
        c++;
    }
    if (star)
        (c-2)->cdr = (c-1)->car;
    else
        (c-1)->cdr = NIL;
    return v;
}

static value_t copy_list(value_t L)
{
    if (!iscons(L))
        return NIL;
    PUSH(NIL);
    PUSH(L);
    value_t *plcons = &Stack[SP-2];
    value_t *pL = &Stack[SP-1];
    value_t c;
    c = mk_cons(); PUSH(c);  // save first cons
    car_(c) = car_(*pL);
    cdr_(c) = NIL;
    *plcons = c;
    *pL = cdr_(*pL);
    while (iscons(*pL)) {
        c = mk_cons();
        car_(c) = car_(*pL);
        cdr_(c) = NIL;
        cdr_(*plcons) = c;
        *plcons = c;
        *pL = cdr_(*pL);
    }
    c = POP();  // first cons
    POPN(2);
    return c;
}

static value_t do_trycatch(void)
{
    uint32_t saveSP = SP;
    value_t v = NIL;
    value_t thunk = Stack[SP-2];
    Stack[SP-2] = Stack[SP-1];
    Stack[SP-1] = thunk;

    FL_TRY {
        v = apply_cl(0);
    }
    FL_CATCH {
        v = Stack[saveSP-2];
        PUSH(v);
        PUSH(fl_lasterror);
        v = apply_cl(1);
    }
    SP = saveSP;
    return v;
}

/*
  argument layout on stack is
  |--required args--|--opt args--|--kw args--|--rest args...
*/
static uint32_t process_keys(value_t kwtable,
                             uint32_t nreq, uint32_t nkw, uint32_t nopt,
                             uint32_t bp, uint32_t nargs, int va)
{
    uint32_t extr = nopt+nkw;
    uint32_t ntot = nreq+extr;
    value_t args[64], v = NIL;
    uint32_t i, a = 0, nrestargs;
    value_t s1 = Stack[SP-1];
    value_t s2 = Stack[SP-2];
    value_t s4 = Stack[SP-4];
    value_t s5 = Stack[SP-5];
    if (nargs < nreq)
        lerrorf(ArgError, "apply: too few arguments");
    if (extr > nelem(args))
        lerrorf(ArgError, "apply: too many arguments");
    for (i=0; i < extr; i++) args[i] = UNBOUND;
    for (i=nreq; i < nargs; i++) {
        v = Stack[bp+i];
        if (issymbol(v) && iskeyword((symbol_t*)ptr(v)))
            break;
        if (a >= nopt)
            goto no_kw;
        args[a++] = v;
    }
    if (i >= nargs) goto no_kw;
    // now process keywords
    uintptr_t n = vector_size(kwtable)/2;
    do {
        i++;
        if (i >= nargs)
            lerrorf(ArgError, "keyword %s requires an argument",
                    symbol_name(v));
        value_t hv = fixnum(((symbol_t*)ptr(v))->hash);
        lltint_t lx = numval(hv);
        uintptr_t x = 2*((lx < 0 ? -lx : lx) % n);
        if (vector_elt(kwtable, x) == v) {
            uintptr_t idx = numval(vector_elt(kwtable, x+1));
            assert(idx < nkw);
            idx += nopt;
            if (args[idx] == UNBOUND) {
                // if duplicate key, keep first value
                args[idx] = Stack[bp+i];
            }
        }
        else {
            lerrorf(ArgError, "unsupported keyword %s", symbol_name(v));
        }
        i++;
        if (i >= nargs) break;
        v = Stack[bp+i];
    } while (issymbol(v) && iskeyword((symbol_t*)ptr(v)));
 no_kw:
    nrestargs = nargs - i;
    if (!va && nrestargs > 0)
        lerrorf(ArgError, "apply: too many arguments");
    nargs = ntot + nrestargs;
    if (nrestargs)
        memmove(&Stack[bp+ntot], &Stack[bp+i], nrestargs*sizeof(value_t));
    memmove(&Stack[bp+nreq], args, extr*sizeof(value_t));
    SP = bp + nargs;
    assert(SP < N_STACK-5);
    PUSH(s5);
    PUSH(s4);
    PUSH(nargs);
    PUSH(s2);
    PUSH(s1);
    curr_frame = SP;
    return nargs;
}

#if BYTE_ORDER == BIG_ENDIAN
#define GET_INT32(a)                            \
    ((int32_t)                                  \
    ((((int32_t)a[0])<<0)  |                    \
     (((int32_t)a[1])<<8)  |                    \
     (((int32_t)a[2])<<16) |                    \
     (((int32_t)a[3])<<24)))
#define GET_INT16(a)                            \
    ((int16_t)                                  \
    ((((int16_t)a[0])<<0)  |                    \
     (((int16_t)a[1])<<8)))
#define PUT_INT32(a,i) (*(int32_t*)(a) = bswap_32((int32_t)(i)))
#else
#define GET_INT32(a) (*(int32_t*)a)
#define GET_INT16(a) (*(int16_t*)a)
#define PUT_INT32(a,i) (*(int32_t*)(a) = (int32_t)(i))
#endif

#define OP(x) case x:
#define NEXT_OP break

/*
  stack on entry: <func>  <nargs args...>
  caller's responsibility:
  - put the stack in this state
  - provide arg count
  - respect tail position
  - restore SP

  callee's responsibility:
  - check arg counts
  - allocate vararg array
  - push closed env, set up new environment
*/
static value_t apply_cl(uint32_t nargs)
{
    uint32_t top_frame = curr_frame;
    // frame variables
    uint32_t n, captured;
    uint32_t bp;
    const uint8_t *ip;
    fixnum_t s, hi;
    int tail;

    // temporary variables (not necessary to preserve across calls)
    uint32_t op, i;
    symbol_t *sym;
    cons_t *c;
    value_t *pv;
    int64_t accum;
    value_t func, v, e;

    n = 0;
    v = 0;
    USED(n);
    USED(v);
 apply_cl_top:
    captured = 0;
    func = Stack[SP-nargs-1];
    ip = cv_data((cvalue_t*)ptr(fn_bcode(func)));
    assert(!ismanaged((uintptr_t)ip));
    while (SP+GET_INT32(ip) > N_STACK) {
        grow_stack();
    }
    ip += 4;

    bp = SP-nargs;
    PUSH(fn_env(func));
    PUSH(curr_frame);
    PUSH(nargs);
    SP++;//PUSH(0); //ip
    PUSH(0); //captured?
    curr_frame = SP;

    op = *ip++;
    while(1){
        if(op < nelem(builtins) && builtins[op].name != nil)
            curr_fname = builtins[op].name;
        switch (op) {
        OP(OP_LOADA0)
            v = captured ? vector_elt(Stack[bp], 0) : Stack[bp];
            PUSH(v);
            NEXT_OP;

        OP(OP_LOADA1)
            v = captured ? vector_elt(Stack[bp], 1) : Stack[bp+1];
            PUSH(v);
            NEXT_OP;

        OP(OP_LOADV)
            v = fn_vals(Stack[bp-1]);
            assert(*ip < vector_size(v));
            v = vector_elt(v, *ip);
            ip++;
            PUSH(v);
            NEXT_OP;

        OP(OP_BRF)
            v = POP();
            ip += v == FL_F ? GET_INT16(ip) : 2;
            NEXT_OP;

        OP(OP_POP)
            POPN(1);
            NEXT_OP;

        OP(OP_TCALLL)
            tail = 1;
            if (0) {
        OP(OP_CALLL)
                tail = 0;
            }
            n = GET_INT32(ip);
            ip += 4;
            if (0) {
        OP(OP_TCALL)
                tail = 1;
                if (0) {
        OP(OP_CALL)
                    tail = 0;
                }
                n = *ip++;  // nargs
            }
        do_call:
            func = Stack[SP-n-1];
            if (tag(func) == TAG_FUNCTION) {
                if (func > (N_BUILTINS<<3)) {
                    if (tail) {
                        curr_frame = Stack[curr_frame-4];
                        for(s=-1; s < (fixnum_t)n; s++)
                            Stack[bp+s] = Stack[SP-n+s];
                        SP = bp+n;
                    } else {
                        Stack[curr_frame-2] = (uintptr_t)ip;
                    }
                    nargs = n;
                    function_t *fn = (function_t*)ptr(func);
                    curr_fname = fn->name == LAMBDA ? "lambda" : symbol_name(fn->name);
                    goto apply_cl_top;
                }
                else {
                    i = uintval(func);
                    if (isbuiltin(func)) {
                        s = builtins[i].nargs;
                        if (s >= 0)
                            argcount(n, s);
                        else if (s != ANYARGS && (signed)n < -s)
                            argcount(n, -s);
                        // remove function arg
                        for(s=SP-n-1; s < (int)SP-1; s++)
                            Stack[s] = Stack[s+1];
                        SP--;
                        curr_fname = builtins[i].name;
                        switch (i) {
                        case OP_LIST:   goto apply_list;
                        case OP_VECTOR: goto apply_vector;
                        case OP_APPLY:  goto apply_apply;
                        case OP_ADD:    goto apply_add;
                        case OP_SUB:    goto apply_sub;
                        case OP_MUL:    goto apply_mul;
                        case OP_DIV:    goto apply_div;
                        default:
                            op = i;
                            continue;
                        }
                    }
                }
            }
            else if (iscbuiltin(func)) {
                s = SP;
                curr_fname = cvalue_name(func);
                v = ((builtin_t)(((void**)ptr(func))[3]))(&Stack[SP-n], n);
                SP = s-n;
                Stack[SP-1] = v;
                NEXT_OP;
            }
            type_error("function", func);

        OP(OP_LOADGL)
            v = fn_vals(Stack[bp-1]);
            v = vector_elt(v, GET_INT32(ip)); ip+=4;
            if (0) {
        OP(OP_LOADG)
                v = fn_vals(Stack[bp-1]);
                assert(*ip < vector_size(v));
                v = vector_elt(v, *ip);
                ip++;
            }
            assert(issymbol(v));
            sym = (symbol_t*)ptr(v);
            if (sym->binding == UNBOUND)
                unbound_error(v);
            PUSH(sym->binding);
            NEXT_OP;

        OP(OP_LOADA)
            assert(nargs > 0);
            i = *ip++;
            if (captured) {
                e = Stack[bp];
                assert(isvector(e));
                assert(i < vector_size(e));
                v = vector_elt(e, i);
            }
            else {
                v = Stack[bp+i];
            }
            PUSH(v);
            NEXT_OP;

        OP(OP_LOADC)
            s = *ip++;
            i = *ip++;
            v = Stack[bp+nargs];
            while (s--)
                v = vector_elt(v, vector_size(v)-1);
            assert(isvector(v));
            assert(i < vector_size(v));
            PUSH(vector_elt(v, i));
            NEXT_OP;

        OP(OP_RET)
            v = POP();
            SP = curr_frame;
            curr_frame = Stack[SP-4];
            if (curr_frame == top_frame)
                return v;
            SP -= (5+nargs);
            captured     = Stack[curr_frame-1];
            ip = (uint8_t*)Stack[curr_frame-2];
            nargs        = Stack[curr_frame-3];
            bp           = curr_frame - 5 - nargs;
            Stack[SP-1] = v;
            NEXT_OP;

        OP(OP_DUP)
            SP++;
            Stack[SP-1] = Stack[SP-2];
            NEXT_OP;

        OP(OP_CAR)
            v = Stack[SP-1];
            if (!iscons(v))
                type_error("cons", v);
            Stack[SP-1] = car_(v);
            NEXT_OP;

        OP(OP_CDR)
            v = Stack[SP-1];
            if (!iscons(v))
                type_error("cons", v);
            Stack[SP-1] = cdr_(v);
            NEXT_OP;

        OP(OP_CLOSURE)
            // build a closure (lambda args body . env)
            if (nargs > 0 && !captured) {
                // save temporary environment to the heap
                n = nargs;
                pv = alloc_words(n + 2);
                PUSH(tagptr(pv, TAG_VECTOR));
                pv[0] = fixnum(n+1);
                pv++;
                do {
                    pv[n] = Stack[bp+n];
                } while (n--);
                // environment representation changed; install
                // the new representation so everybody can see it
                captured = 1;
                Stack[curr_frame-1] = 1;
                Stack[bp] = Stack[SP-1];
            }
            else {
                PUSH(Stack[bp]); // env has already been captured; share
            }
            if (curheap > lim-2)
                gc(0);
            pv = (value_t*)curheap;
            curheap += (4*sizeof(value_t));
            e = Stack[SP-2];  // closure to copy
            assert(isfunction(e));
            pv[0] = ((value_t*)ptr(e))[0];
            pv[1] = ((value_t*)ptr(e))[1];
            pv[2] = Stack[SP-1];  // env
            pv[3] = ((value_t*)ptr(e))[3];
            POPN(1);
            Stack[SP-1] = tagptr(pv, TAG_FUNCTION);
            NEXT_OP;

        OP(OP_SETA)
            assert(nargs > 0);
            v = Stack[SP-1];
            i = *ip++;
            if (captured) {
                e = Stack[bp];
                assert(isvector(e));
                assert(i < vector_size(e));
                vector_elt(e, i) = v;
            }
            else {
                Stack[bp+i] = v;
            }
            NEXT_OP;

        OP(OP_JMP)
            ip += GET_INT16(ip);
            NEXT_OP;

        OP(OP_LOADC00)
            PUSH(vector_elt(Stack[bp+nargs], 0));
            NEXT_OP;

        OP(OP_PAIRP)
            Stack[SP-1] = iscons(Stack[SP-1]) ? FL_T : FL_F;
            NEXT_OP;

        OP(OP_BRNE)
            ip += Stack[SP-2] != Stack[SP-1] ? GET_INT16(ip) : 2;
            POPN(2);
            NEXT_OP;

        OP(OP_LOADT)
            PUSH(FL_T);
            NEXT_OP;

        OP(OP_LOAD0)
            PUSH(fixnum(0));
            NEXT_OP;

        OP(OP_LOADC01)
            PUSH(vector_elt(Stack[bp+nargs], 1));
            NEXT_OP;

        OP(OP_AREF)
            v = Stack[SP-2];
            if (isvector(v)) {
                e = Stack[SP-1];
                i = isfixnum(e) ? numval(e) : (uint32_t)toulong(e);
                if ((unsigned)i >= vector_size(v))
                    bounds_error(v, e);
                v = vector_elt(v, i);
            }
            else if (isarray(v)) {
                v = cvalue_array_aref(&Stack[SP-2]);
            }
            else {
                type_error("sequence", v);
            }
            POPN(1);
            Stack[SP-1] = v;
            NEXT_OP;

        OP(OP_ATOMP)
            Stack[SP-1] = iscons(Stack[SP-1]) ? FL_F : FL_T;
            NEXT_OP;

        OP(OP_BRT)
            v = POP();
            ip += v != FL_F ? GET_INT16(ip) : 2;
            NEXT_OP;

        OP(OP_BRNN)
            v = POP();
            ip += v != NIL ? GET_INT16(ip) : 2;
            NEXT_OP;

        OP(OP_LOAD1)
            PUSH(fixnum(1));
            NEXT_OP;

        OP(OP_LT)
            if (bothfixnums(Stack[SP-2], Stack[SP-1]))
                v = numval(Stack[SP-2]) < numval(Stack[SP-1]) ? FL_T : FL_F;
            else
                v = numval(fl_compare(Stack[SP-2], Stack[SP-1])) < 0 ? FL_T : FL_F;
            POPN(1);
            Stack[SP-1] = v;
            NEXT_OP;

        OP(OP_ADD2)
            if (bothfixnums(Stack[SP-1], Stack[SP-2])) {
                s = numval(Stack[SP-1]) + numval(Stack[SP-2]);
                v = fits_fixnum(s) ? fixnum(s) : mk_xlong(s);
            }
            else {
                v = fl_add_any(&Stack[SP-2], 2, 0);
            }
            POPN(1);
            Stack[SP-1] = v;
            NEXT_OP;

        OP(OP_SETCDR)
            cdr(Stack[SP-2]) = Stack[SP-1];
            POPN(1);
            NEXT_OP;

        OP(OP_LOADF)
            PUSH(FL_F);
            NEXT_OP;

        OP(OP_CONS)
            if (curheap > lim)
                gc(0);
            c = (cons_t*)curheap;
            curheap += sizeof(cons_t);
            c->car = Stack[SP-2];
            c->cdr = Stack[SP-1];
            Stack[SP-2] = tagptr(c, TAG_CONS);
            POPN(1); NEXT_OP;

        OP(OP_EQ)
            Stack[SP-2] = Stack[SP-2] == Stack[SP-1] ? FL_T : FL_F;
            POPN(1);
            NEXT_OP;

        OP(OP_SYMBOLP)
            Stack[SP-1] = issymbol(Stack[SP-1]) ? FL_T : FL_F;
            NEXT_OP;

        OP(OP_NOT)
            Stack[SP-1] = Stack[SP-1]==FL_F ? FL_T : FL_F;
            NEXT_OP;

        OP(OP_CADR)
            v = Stack[SP-1];
            if (!iscons(v))
                type_error("cons", v);
            v = cdr_(v);
            if (!iscons(v))
                type_error("cons", v);
            Stack[SP-1] = car_(v);
            NEXT_OP;

        OP(OP_NEG)
        do_neg:
            Stack[SP-1] = fl_neg(Stack[SP-1]);
            NEXT_OP;

        OP(OP_NULLP)
            Stack[SP-1] = Stack[SP-1]==NIL ? FL_T : FL_F;
            NEXT_OP;

        OP(OP_BOOLEANP)
            v = Stack[SP-1];
            Stack[SP-1] = (v == FL_T || v == FL_F) ? FL_T:FL_F;
            NEXT_OP;

        OP(OP_NUMBERP)
            v = Stack[SP-1];
            Stack[SP-1] = fl_isnumber(v) ? FL_T:FL_F;
            NEXT_OP;

        OP(OP_FIXNUMP)
            Stack[SP-1] = isfixnum(Stack[SP-1]) ? FL_T : FL_F;
            NEXT_OP;

        OP(OP_BOUNDP)
            sym = tosymbol(Stack[SP-1]);
            Stack[SP-1] = sym->binding == UNBOUND ? FL_F : FL_T;
            NEXT_OP;

        OP(OP_BUILTINP)
            v = Stack[SP-1];
            Stack[SP-1] = (isbuiltin(v) || iscbuiltin(v)) ? FL_T : FL_F;
            NEXT_OP;

        OP(OP_FUNCTIONP)
            v = Stack[SP-1];
            Stack[SP-1] = ((tag(v)==TAG_FUNCTION &&
                            (isbuiltin(v) || v>(N_BUILTINS<<3))) ||
                           iscbuiltin(v)) ? FL_T : FL_F;
            NEXT_OP;

        OP(OP_VECTORP)
            Stack[SP-1] = isvector(Stack[SP-1]) ? FL_T : FL_F;
            NEXT_OP;

        OP(OP_JMPL)
            ip += GET_INT32(ip);
            NEXT_OP;

        OP(OP_BRFL)
            ip += POP() == FL_F ? GET_INT32(ip) : 4;
            NEXT_OP;

        OP(OP_BRTL)
            ip += POP() != FL_F ? GET_INT32(ip) : 4;
            NEXT_OP;

        OP(OP_BRNEL)
            ip += Stack[SP-2] != Stack[SP-1] ? GET_INT32(ip) : 4;
            POPN(2);
            NEXT_OP;

        OP(OP_BRNNL)
            ip += POP() != NIL ? GET_INT32(ip) : 4;
            NEXT_OP;

        OP(OP_BRN)
            ip += POP() == NIL ? GET_INT16(ip) : 2;
            NEXT_OP;

        OP(OP_BRNL)
            ip += POP() == NIL ? GET_INT32(ip) : 4;
            NEXT_OP;

        OP(OP_EQV)
            if (Stack[SP-2] == Stack[SP-1])
                v = FL_T;
            else if (!leafp(Stack[SP-2]) || !leafp(Stack[SP-1]))
                v = FL_F;
            else
                v = (compare_(Stack[SP-2], Stack[SP-1], 1)==0 ? FL_T : FL_F);
            Stack[SP-2] = v;
            POPN(1);
            NEXT_OP;

        OP(OP_EQUAL)
            if (Stack[SP-2] == Stack[SP-1])
                v = FL_T;
            else
                v = (compare_(Stack[SP-2], Stack[SP-1], 1)==0 ? FL_T : FL_F);
            Stack[SP-2] = v;
            POPN(1);
            NEXT_OP;

        OP(OP_SETCAR)
            car(Stack[SP-2]) = Stack[SP-1];
            POPN(1);
            NEXT_OP;

        OP(OP_LIST)
            n = *ip++;
        apply_list:
            if (n > 0) {
                v = list(&Stack[SP-n], n, 0);
                POPN(n);
                PUSH(v);
            }
            else {
                PUSH(NIL);
            }
            NEXT_OP;

        OP(OP_TAPPLY)
            tail = 1;
            if (0) {
        OP(OP_APPLY)
                tail = 0;
            }
            n = *ip++;
        apply_apply:
            v = POP();     // arglist
            n = SP-(n-2);  // n-2 == # leading arguments not in the list
            while (iscons(v)) {
                if (SP >= N_STACK)
                    grow_stack();
                PUSH(car_(v));
                v = cdr_(v);
            }
            n = SP-n;
            goto do_call;

        OP(OP_ADD)
            n = *ip++;
        apply_add:
            s = 0;
            i = SP-n;
            for (; i < SP; i++) {
                if (isfixnum(Stack[i])) {
                    s += numval(Stack[i]);
                    if (!fits_fixnum(s)) {
                        i++;
                        goto add_ovf;
                    }
                }
                else {
                add_ovf:
                    v = fl_add_any(&Stack[i], SP-i, s);
                    break;
                }
            }
            if (i==SP)
                v = fixnum(s);
            POPN(n);
            PUSH(v);
            NEXT_OP;

        OP(OP_SUB)
            n = *ip++;
        apply_sub:
            if (n == 2)
                goto do_sub2;
            if (n == 1)
                goto do_neg;
            i = SP-n;
            // we need to pass the full arglist on to fl_add_any
            // so it can handle rest args properly
            PUSH(Stack[i]);
            Stack[i] = fixnum(0);
            Stack[i+1] = fl_neg(fl_add_any(&Stack[i], n, 0));
            Stack[i] = POP();
            v = fl_add_any(&Stack[i], 2, 0);
            POPN(n);
            PUSH(v);
            NEXT_OP;

        OP(OP_SUB2)
        do_sub2:
            if (bothfixnums(Stack[SP-2], Stack[SP-1])) {
                s = numval(Stack[SP-2]) - numval(Stack[SP-1]);
                v = fits_fixnum(s) ? fixnum(s) : mk_xlong(s);
            }
            else {
                Stack[SP-1] = fl_neg(Stack[SP-1]);
                v = fl_add_any(&Stack[SP-2], 2, 0);
            }
            POPN(1);
            Stack[SP-1] = v;
            NEXT_OP;

        OP(OP_MUL)
            n = *ip++;
        apply_mul:
            accum = 1;
            i = SP-n;
            for (; i < SP; i++) {
                if (isfixnum(Stack[i])) {
                    accum *= numval(Stack[i]);
                }
                else {
                    v = fl_mul_any(&Stack[i], SP-i, accum);
                    break;
                }
            }
            if (i == SP)
                v = fits_fixnum(accum) ? fixnum(accum) : return_from_int64(accum);
            POPN(n);
            PUSH(v);
            NEXT_OP;

        OP(OP_DIV)
            n = *ip++;
        apply_div:
            i = SP-n;
            if (n == 1) {
                Stack[SP-1] = fl_div2(fixnum(1), Stack[i]);
            }
            else {
                if (n > 2) {
                    PUSH(Stack[i]);
                    Stack[i] = fixnum(1);
                    Stack[i+1] = fl_mul_any(&Stack[i], n, 1);
                    Stack[i] = POP();
                }
                v = fl_div2(Stack[i], Stack[i+1]);
                POPN(n);
                PUSH(v);
            }
            NEXT_OP;

        OP(OP_IDIV)
            v = Stack[SP-2]; e = Stack[SP-1];
            if (bothfixnums(v, e)) {
                if (e==0) DivideByZeroError();
                v = fixnum(numval(v) / numval(e));
            }
            else
                v = fl_idiv2(v, e);
            POPN(1);
            Stack[SP-1] = v;
            NEXT_OP;

        OP(OP_NUMEQ)
            v = Stack[SP-2]; e = Stack[SP-1];
            if (bothfixnums(v, e))
                v = v == e ? FL_T : FL_F;
            else
                v = !numeric_compare(v,e,1,0,1) ? FL_T : FL_F;
            POPN(1);
            Stack[SP-1] = v;
            NEXT_OP;

        OP(OP_COMPARE)
            Stack[SP-2] = compare_(Stack[SP-2], Stack[SP-1], 0);
            POPN(1);
            NEXT_OP;

        OP(OP_ARGC)
            n = *ip++;
            if (0) {
        OP(OP_LARGC)
                n = GET_INT32(ip);
                ip += 4;
            }
            if (nargs != n)
                lerrorf(ArgError, "too %s arguments", nargs > n ? "many" : "few");
            NEXT_OP;

        OP(OP_VECTOR)
            n = *ip++;
        apply_vector:
            v = alloc_vector(n, 0);
            if (n) {
                memmove(&vector_elt(v,0), &Stack[SP-n], n*sizeof(value_t));
                POPN(n);
            }
            PUSH(v);
            NEXT_OP;

        OP(OP_ASET)
            e = Stack[SP-3];
            if (isvector(e)) {
                i = tofixnum(Stack[SP-2]);
                if ((unsigned)i >= vector_size(e))
                    bounds_error(v, Stack[SP-1]);
                vector_elt(e, i) = (v=Stack[SP-1]);
            }
            else if (isarray(e)) {
                v = cvalue_array_aset(&Stack[SP-3]);
            }
            else {
                type_error("sequence", e);
            }
            POPN(2);
            Stack[SP-1] = v;
            NEXT_OP;

        OP(OP_FOR)
            s  = tofixnum(Stack[SP-3]);
            hi = tofixnum(Stack[SP-2]);
            //f = Stack[SP-1];
            v = FL_UNSPECIFIED;
            SP += 2;
            n = SP;
            for(; s <= hi; s++) {
                Stack[SP-2] = Stack[SP-3];
                Stack[SP-1] = fixnum(s);
                v = apply_cl(1);
                SP = n;
            }
            POPN(4);
            Stack[SP-1] = v;
            NEXT_OP;

        OP(OP_LOADNIL)
            PUSH(NIL);
            NEXT_OP;

        OP(OP_LOADI8)
            s = (int8_t)*ip++;
            PUSH(fixnum(s));
            NEXT_OP;

        OP(OP_LOADVL)
            v = fn_vals(Stack[bp-1]);
            v = vector_elt(v, GET_INT32(ip));
            ip += 4;
            PUSH(v);
            NEXT_OP;

        OP(OP_SETGL)
            v = fn_vals(Stack[bp-1]);
            v = vector_elt(v, GET_INT32(ip));
            ip += 4;
            if (0) {
        OP(OP_SETG)
                v = fn_vals(Stack[bp-1]);
                assert(*ip < vector_size(v));
                v = vector_elt(v, *ip);
                ip++;
            }
            assert(issymbol(v));
            sym = (symbol_t*)ptr(v);
            v = Stack[SP-1];
            if (!isconstant(sym))
                sym->binding = v;
            NEXT_OP;

        OP(OP_LOADAL)
            assert(nargs > 0);
            i = GET_INT32(ip);
            ip += 4;
            v = captured ? vector_elt(Stack[bp], i) : Stack[bp+i];
            PUSH(v);
            NEXT_OP;

        OP(OP_SETAL)
            assert(nargs > 0);
            v = Stack[SP-1];
            i = GET_INT32(ip); ip+=4;
            if (captured)
                vector_elt(Stack[bp], i) = v;
            else
                Stack[bp+i] = v;
            NEXT_OP;

        OP(OP_SETC)
            s = *ip++;
            i = *ip++;
            v = Stack[bp+nargs];
            while (s--)
                v = vector_elt(v, vector_size(v)-1);
            assert(isvector(v));
            assert(i < vector_size(v));
            vector_elt(v, i) = Stack[SP-1];
            NEXT_OP;

        OP(OP_LOADCL)
            s = GET_INT32(ip); ip+=4;
            i = GET_INT32(ip); ip+=4;
            v = Stack[bp+nargs];
            while (s--)
                v = vector_elt(v, vector_size(v)-1);
            PUSH(vector_elt(v, i));
            NEXT_OP;

        OP(OP_SETCL)
            s = GET_INT32(ip);
            ip += 4;
            i = GET_INT32(ip);
            ip += 4;
            v = Stack[bp+nargs];
            while (s--)
                v = vector_elt(v, vector_size(v)-1);
            assert(i < vector_size(v));
            vector_elt(v, i) = Stack[SP-1];
            NEXT_OP;

        OP(OP_VARGC)
            i = *ip++;
            if (0) {
        OP(OP_LVARGC)
                i = GET_INT32(ip);
                ip += 4;
            }
            s = (fixnum_t)nargs - (fixnum_t)i;
            if (s > 0) {
                v = list(&Stack[bp+i], s, 0);
                Stack[bp+i] = v;
                if (s > 1) {
                    Stack[bp+i+1] = Stack[bp+nargs+0];
                    Stack[bp+i+2] = Stack[bp+nargs+1];
                    Stack[bp+i+3] = i+1;
                    //Stack[bp+i+4] = 0;
                    Stack[bp+i+5] = 0;
                    SP =  bp+i+6;
                    curr_frame = SP;
                }
            }
            else if (s < 0) {
                lerrorf(ArgError, "apply: too few arguments");
            }
            else {
                PUSH(0);
                Stack[SP-3] = i+1;
                Stack[SP-4] = Stack[SP-5];
                Stack[SP-5] = Stack[SP-6];
                Stack[SP-6] = NIL;
                curr_frame = SP;
            }
            nargs = i+1;
            NEXT_OP;

        OP(OP_TRYCATCH)
            v = do_trycatch();
            POPN(1);
            Stack[SP-1] = v;
            NEXT_OP;

        OP(OP_OPTARGS)
            i = GET_INT32(ip); ip+=4;
            n = GET_INT32(ip); ip+=4;
            if (nargs < i)
                lerrorf(ArgError, "apply: too few arguments");
            if ((int32_t)n > 0) {
                if (nargs > n)
                    lerrorf(ArgError, "apply: too many arguments");
            }
            else n = -n;
            if (n > nargs) {
                n -= nargs;
                SP += n;
                Stack[SP-1] = Stack[SP-n-1];
                Stack[SP-2] = Stack[SP-n-2];
                Stack[SP-3] = nargs+n;
                Stack[SP-4] = Stack[SP-n-4];
                Stack[SP-5] = Stack[SP-n-5];
                curr_frame = SP;
                for(i=0; i < n; i++) {
                    Stack[bp+nargs+i] = UNBOUND;
                }
                nargs += n;
            }
            NEXT_OP;

        OP(OP_BRBOUND)
            i = GET_INT32(ip); ip+=4;
            v = captured ? vector_elt(Stack[bp], i) : Stack[bp+i];
            PUSH(v != UNBOUND ? FL_T : FL_F);
            NEXT_OP;

        OP(OP_KEYARGS)
            v = fn_vals(Stack[bp-1]);
            v = vector_elt(v, 0);
            i = GET_INT32(ip); ip+=4;
            n = GET_INT32(ip); ip+=4;
            s = GET_INT32(ip); ip+=4;
            nargs = process_keys(v, i, n, labs(s)-(i+n), bp, nargs, s<0);
            NEXT_OP;
        }
        op = *ip++;
    }
}

#define SWAP_INT32(a)
#define SWAP_INT16(a)
#include "maxstack.inc"

#if BYTE_ORDER == BIG_ENDIAN
#undef SWAP_INT32
#undef SWAP_INT16
#define SWAP_INT32(a) (*(int32_t*)(a) = bswap_32(*(int32_t*)(a)))
#define SWAP_INT16(a) (*(int16_t*)(a) = bswap_16(*(int16_t*)(a)))
#define compute_maxstack compute_maxstack_swap
#include "maxstack.inc"
#undef compute_maxstack
#else
#endif

// top = top frame pointer to start at
static value_t _stacktrace(uint32_t top)
{
    uint32_t bp, sz;
    value_t v, lst = NIL;
    fl_gc_handle(&lst);
    while (top > 0) {
        sz = Stack[top-3]+1;
        bp = top-5-sz;
        v = alloc_vector(sz, 0);
        if (Stack[top-1] /*captured*/) {
            vector_elt(v, 0) = Stack[bp];
            memmove(&vector_elt(v, 1),
                   &vector_elt(Stack[bp+1],0), (sz-1)*sizeof(value_t));
        }
        else {
            uint32_t i;
            for(i=0; i < sz; i++) {
                value_t si = Stack[bp+i];
                // if there's an error evaluating argument defaults some slots
                // might be left set to UNBOUND (issue #22)
                vector_elt(v,i) = (si == UNBOUND ? FL_UNSPECIFIED : si);
            }
        }
        lst = fl_cons(v, lst);
        top = Stack[top-4];
    }
    fl_free_gc_handles(1);
    return lst;
}

// builtins -------------------------------------------------------------------

BUILTIN("function", function)
{
    if (nargs == 1 && issymbol(args[0]))
        return fn_builtin_builtin(args, nargs);
    if (nargs < 2 || nargs > 4)
        argcount(nargs, 2);
    if (!fl_isstring(args[0]))
        type_error("string", args[0]);
    if (!isvector(args[1]))
        type_error("vector", args[1]);
    cvalue_t *arr = (cvalue_t*)ptr(args[0]);
    cv_pin(arr);
    char *data = cv_data(arr);
    uint32_t ms;
    if ((uint8_t)data[4] >= N_OPCODES) {
        // read syntax, shifted 48 for compact text representation
        size_t i, sz = cv_len(arr);
        for(i=0; i < sz; i++)
            data[i] -= 48;
#if BYTE_ORDER == BIG_ENDIAN
        ms = compute_maxstack((uint8_t*)data, cv_len(arr));
    } else {
        ms = compute_maxstack_swap((uint8_t*)data, cv_len(arr));
    }
#else
    }
    ms = compute_maxstack((uint8_t*)data, cv_len(arr));
#endif
    PUT_INT32(data, ms);
    function_t *fn = (function_t*)alloc_words(4);
    value_t fv = tagptr(fn, TAG_FUNCTION);
    fn->bcode = args[0];
    fn->vals = args[1];
    fn->env = NIL;
    fn->name = LAMBDA;
    if (nargs > 2) {
        if (issymbol(args[2])) {
            fn->name = args[2];
            if (nargs > 3)
                fn->env = args[3];
        }
        else {
            fn->env = args[2];
            if (nargs > 3) {
                if (!issymbol(args[3]))
                    type_error("symbol", args[3]);
                fn->name = args[3];
            }
        }
        if (isgensym(fn->name))
            lerrorf(ArgError, "function: name should not be a gensym");
    }
    return fv;
}

BUILTIN("function:code", function_code)
{
    argcount(nargs, 1);
    value_t v = args[0];
    if (!isclosure(v)) type_error("function", v);
    return fn_bcode(v);
}
BUILTIN("function:vals", function_vals)
{
    argcount(nargs, 1);
    value_t v = args[0];
    if (!isclosure(v)) type_error("function", v);
    return fn_vals(v);
}
BUILTIN("function:env", function_env)
{
    argcount(nargs, 1);
    value_t v = args[0];
    if (!isclosure(v)) type_error("function", v);
    return fn_env(v);
}
BUILTIN("function:name", function_name)
{
    argcount(nargs, 1);
    value_t v = args[0];
    if (!isclosure(v)) type_error("function", v);
    return fn_name(v);
}

BUILTIN("copy-list", copy_list)
{
    argcount(nargs, 1);
    return copy_list(args[0]);
}

BUILTIN("append", append)
{
    value_t first=NIL, lst, lastcons=NIL;
    int i;
    if (nargs == 0)
        return NIL;
    fl_gc_handle(&first);
    fl_gc_handle(&lastcons);
    for (i = 0; i < nargs; i++) {
        lst = args[i];
        if (iscons(lst)) {
            lst = copy_list(lst);
            if (first == NIL)
                first = lst;
            else
                cdr_(lastcons) = lst;
            lastcons = tagptr((((cons_t*)curheap)-1), TAG_CONS);
        }
        else if (lst != NIL) {
            type_error("cons", lst);
        }
    }
    fl_free_gc_handles(2);
    return first;
}

BUILTIN("list*", liststar)
{
    if (nargs == 1) return args[0];
    else if (nargs == 0) argcount(nargs, 1);
    return list(args, nargs, 1);
}

BUILTIN("stacktrace", stacktrace)
{
    USED(args);
    argcount(nargs, 0);
    return _stacktrace(fl_throwing_frame ? fl_throwing_frame : curr_frame);
}

BUILTIN("map", map)
{
    if (nargs < 2)
        lerrorf(ArgError, "map: too few arguments");
    if (!iscons(args[1])) return NIL;
    value_t first, last, v;
    int64_t argSP = args-Stack;
    assert(argSP >= 0 && argSP < N_STACK);
    if (nargs == 2) {
        if (SP+3 > N_STACK) grow_stack();
        PUSH(Stack[argSP]);
        PUSH(car_(Stack[argSP+1]));
        v = _applyn(1);
        PUSH(v);
        v = mk_cons();
        car_(v) = POP(); cdr_(v) = NIL;
        last = first = v;
        Stack[argSP+1] = cdr_(Stack[argSP+1]);
        fl_gc_handle(&first);
        fl_gc_handle(&last);
        while (iscons(Stack[argSP+1])) {
            Stack[SP-2] = Stack[argSP];
            Stack[SP-1] = car_(Stack[argSP+1]);
            v = _applyn(1);
            PUSH(v);
            v = mk_cons();
            car_(v) = POP(); cdr_(v) = NIL;
            cdr_(last) = v;
            last = v;
            Stack[argSP+1] = cdr_(Stack[argSP+1]);
        }
        POPN(2);
        fl_free_gc_handles(2);
    }
    else {
        int i;
        while (SP+nargs+1 > N_STACK) grow_stack();
        PUSH(Stack[argSP]);
        for(i=1; i < nargs; i++) {
            PUSH(car(Stack[argSP+i]));
            Stack[argSP+i] = cdr_(Stack[argSP+i]);
        }
        v = _applyn(nargs-1);
        POPN(nargs);
        PUSH(v);
        v = mk_cons();
        car_(v) = POP(); cdr_(v) = NIL;
        last = first = v;
        fl_gc_handle(&first);
        fl_gc_handle(&last);
        while (iscons(Stack[argSP+1])) {
            PUSH(Stack[argSP]);
            for(i=1; i < nargs; i++) {
                PUSH(car(Stack[argSP+i]));
                Stack[argSP+i] = cdr_(Stack[argSP+i]);
            }
            v = _applyn(nargs-1);
            POPN(nargs);
            PUSH(v);
            v = mk_cons();
            car_(v) = POP(); cdr_(v) = NIL;
            cdr_(last) = v;
            last = v;
        }
        fl_free_gc_handles(2);
    }
    return first;
}

#define BUILTIN_FN(l,c) extern BUILTIN(l,c);
#include "builtin_fns.h"
#undef BUILTIN_FN

static const builtinspec_t builtin_fns[] = {
#define BUILTIN_FN(l,c) {l,fn_builtin_##c},
#include "builtin_fns.h"
#undef BUILTIN_FN
};

// initialization -------------------------------------------------------------

extern void builtins_init(void);
extern void comparehash_init(void);

static void lisp_init(size_t initial_heapsize)
{
    int i;

    llt_init();
    setlocale(LC_NUMERIC, "C");

    heapsize = initial_heapsize;

    fromspace = LLT_ALLOC(heapsize);
    tospace   = LLT_ALLOC(heapsize);
    curheap = fromspace;
    lim = curheap+heapsize-sizeof(cons_t);
    consflags = bitvector_new(heapsize/sizeof(cons_t), 1);
    htable_new(&printconses, 32);
    comparehash_init();
    N_STACK = 262144;
    Stack = malloc(N_STACK*sizeof(value_t));

    FL_NIL = NIL = builtin(OP_THE_EMPTY_LIST);
    FL_T = builtin(OP_BOOL_CONST_T);
    FL_F = builtin(OP_BOOL_CONST_F);
    FL_EOF = builtin(OP_EOF_OBJECT);
    LAMBDA = symbol("lambda");        FUNCTION = symbol("function");
    QUOTE = symbol("quote");          TRYCATCH = symbol("trycatch");
    BACKQUOTE = symbol("quasiquote");       COMMA = symbol("unquote");
    COMMAAT = symbol("unquote-splicing");   COMMADOT = symbol("unquote-nsplicing");
    IOError = symbol("io-error");     ParseError = symbol("parse-error");
    TypeError = symbol("type-error"); ArgError = symbol("arg-error");
    UnboundError = symbol("unbound-error");
    KeyError = symbol("key-error");   MemoryError = symbol("memory-error");
    BoundsError = symbol("bounds-error");
    DivideError = symbol("divide-error");
    EnumerationError = symbol("enumeration-error");
    Error = symbol("error");          pairsym = symbol("pair");
    symbolsym = symbol("symbol");     fixnumsym = symbol("fixnum");
    vectorsym = symbol("vector");     builtinsym = symbol("builtin");
    booleansym = symbol("boolean");   nullsym = symbol("null");
    definesym = symbol("define");     defmacrosym = symbol("define-macro");
    forsym = symbol("for");
    setqsym = symbol("set!");         evalsym = symbol("eval");
    vu8sym = symbol("vu8");           fnsym = symbol("fn");
    nulsym = symbol("nul");           alarmsym = symbol("alarm");
    backspacesym = symbol("backspace"); tabsym = symbol("tab");
    linefeedsym = symbol("linefeed"); vtabsym = symbol("vtab");
    pagesym = symbol("page");         returnsym = symbol("return");
    escsym = symbol("esc");           spacesym = symbol("space");
    deletesym = symbol("delete");     newlinesym = symbol("newline");
    tsym = symbol("t"); Tsym = symbol("T");
    fsym = symbol("f"); Fsym = symbol("F");
    set(printprettysym=symbol("*print-pretty*"), FL_T);
    set(printreadablysym=symbol("*print-readably*"), FL_T);
    set(printwidthsym=symbol("*print-width*"), fixnum(SCR_WIDTH));
    set(printlengthsym=symbol("*print-length*"), FL_F);
    set(printlevelsym=symbol("*print-level*"), FL_F);
    builtins_table_sym = symbol("*builtins*");
    fl_lasterror = NIL;
    for (i=0; i < nelem(builtins); i++) {
        if (builtins[i].name)
            setc(symbol(builtins[i].name), builtin(i));
    }
    setc(symbol("eq"), builtin(OP_EQ));
    setc(symbol("procedure?"), builtin(OP_FUNCTIONP));
    setc(symbol("top-level-bound?"), builtin(OP_BOUNDP));

#if defined(__linux__)
    set(symbol("*os-name*"), symbol("linux"));
#elif defined(__OpenBSD__)
    set(symbol("*os-name*"), symbol("openbsd"));
#elif defined(__FreeBSD__)
    set(symbol("*os-name*"), symbol("freebsd"));
#elif defined(__NetBSD__)
    set(symbol("*os-name*"), symbol("netbsd"));
#elif defined(__plan9__)
    set(symbol("*os-name*"), symbol("plan9"));
#else
    set(symbol("*os-name*"), symbol("unknown"));
#endif

    the_empty_vector = tagptr(alloc_words(1), TAG_VECTOR);
    vector_setsize(the_empty_vector, 0);

    cvalues_init();

    memory_exception_value = fl_list2(MemoryError,
                                      cvalue_static_cstring("out of memory"));
    const builtinspec_t *b;
    for(i = 0, b = builtin_fns; i < nelem(builtin_fns); i++, b++)
        setc(symbol(b->name), cbuiltin(b->name, b->fptr));

    builtins_init();
}

// top level ------------------------------------------------------------------

value_t fl_toplevel_eval(value_t expr)
{
    return fl_applyn(1, symbol_value(evalsym), expr);
}

void fl_init(size_t initial_heapsize)
{
#ifdef BOEHM_GC
    GC_init();
#endif
    lisp_init(initial_heapsize);
}

int fl_load_system_image(value_t sys_image_iostream)
{
    value_t e;
    int saveSP;
    symbol_t *sym;

    PUSH(sys_image_iostream);
    saveSP = SP;
    FL_TRY {
        curr_fname = "bootstrap";
        while (1) {
            e = fl_read_sexpr(Stack[SP-1]);
            if (ios_eof(value2c(ios_t*,Stack[SP-1]))) break;
            if (isfunction(e)) {
                // stage 0 format: series of thunks
                PUSH(e);
                (void)_applyn(0);
                SP = saveSP;
            }
            else {
                // stage 1 format: list alternating symbol/value
                while (iscons(e)) {
                    sym = tosymbol(car_(e));
                    e = cdr_(e);
                    (void)tocons(e);
                    sym->binding = car_(e);
                    e = cdr_(e);
                }
                break;
            }
        }
    }
    FL_CATCH_NO_INC {
        ios_puts("fatal error during bootstrap:\n", ios_stderr);
        fl_print(ios_stderr, fl_lasterror);
        ios_putc('\n', ios_stderr);
        return 1;
    }
    ios_close(value2c(ios_t*,Stack[SP-1]));
    POPN(1);
    return 0;
}