Lots of changes with long commit message again

1. (list ...)
2. string-* functions
3. (native str) to resolve native functions at runtime
4. Memory fuckups in compiler core unit loading
5. Now can call non-identifiers in compiler

Makefile

@@ -9,6 +9,7 @@ VM_OBJS=$(O)/vm/main.o \
 		$(O)/vm/stack.o \
 		$(O)/vm/error.o \
 		$(O)/vm/debug.o \
+		$(O)/vm/libcore.o \
 		$(O)/core/vector.o \
 		$(O)/core/hash.o
 COMPILER_OBJS=$(O)/compiler/main.o \

compiler/builtin.c

@@ -9,6 +9,17 @@
 #include <string.h>
 #include <stdio.h>
 
+static void emit_rev_cons(struct function *fn,
+                          struct context *ctx,
+                          struct node *args) {
+    if (null_q(args)) {
+        return;
+    }
+    emit_rev_cons(fn, ctx, cdr(args));
+    emit(fn, ctx, car(args));
+    emit_insn(fn, OP(OP_CONS, 0));
+}
+
 int emit_builtin_syntax(struct function *fn,
                         struct context *ctx,
                         const char *name,
@@ -154,6 +165,10 @@ int emit_builtin_syntax(struct function *fn,
         cond_jmp = vector_ref(&fn->bytecode, cond_jmp_loc);
         *cond_jmp |= (end_loc - cond_jmp_loc) & 0xFFFFFF;
         return 0;
+    } else if (!strcmp(name, "list")) {
+        emit_insn(fn, OP(OP_LDNIL, 0));
+        emit_rev_cons(fn, ctx, tail);
+        return 0;
     } else if (!strcmp(name, "use") ||
                !strcmp(name, "export")) {
         // Ignore

compiler/compile.c

@@ -22,6 +22,11 @@ void emit_function(struct context *ctx, struct function *fn) {
     struct unit *root = ctx->root;
     assert(ctx->owner == fn);
 
+    fn->argc = 0;
+    for (struct node *node = fn->args; node; node = cdr(node)) {
+        ++fn->argc;
+    }
+
     // Pass 0 - extract global scope
     for (struct node *node = body; node; node = cdr(node)) {
         struct node *expr = car(node);
@@ -124,6 +129,7 @@ void emit(struct function *fn, struct context *ctx, struct node *expr) {
         return;
     }
     struct node *n0;
+    size_t index;
     int c0;
 
     switch (expr->type) {
@@ -135,11 +141,8 @@ void emit(struct function *fn, struct context *ctx, struct node *expr) {
             fprintf(stderr, "Call to nil\n");
             abort();
         }
-        if (n0->type != N_IDENT) {
-            fprintf(stderr, "TODO non-identifier calls\n");
-            abort();
-        }
 
+        if (n0->type == N_IDENT) {
             // Try builtin syntax construct
             if (emit_builtin_syntax(fn, ctx, n0->n_ident, cdr(expr)) == 0) {
                 return;
@@ -156,11 +159,21 @@ void emit(struct function *fn, struct context *ctx, struct node *expr) {
             // call
             emit_call(fn, ctx, n0->n_ident);
             return;
+        } else {
+            c0 = emit_arg_list(fn, ctx, expr->n_cons.cdr);
+            emit(fn, ctx, n0);
+            emit_insn(fn, OP(OP_CALL, 0));
+            return;
+        }
+    case N_STRING:
+        assert(unit_insert_string(ctx->root, expr->n_string, &index) == 0);
+        emit_insn(fn, OP(OP_LDS, index));
+        return;
     case N_INTEGER:
         if (expr->n_integer < 0x7FFFFF && expr->n_integer > -0x7FFFFF) {
             emit_insn(fn, OP(OP_LDI, expr->n_integer));
         } else {
-            printf("ldc ...\n");
+            assert(0 && "TODO constant pool lmao");
         }
         return;
     case N_IDENT:

compiler/include/node.h

@@ -6,7 +6,8 @@
 enum node_type {
     N_CONS,
     N_IDENT,
-    N_INTEGER
+    N_INTEGER,
+    N_STRING
 };
 
 struct node {
@@ -16,6 +17,7 @@ struct node {
             struct node *car, *cdr;
         } n_cons;
         char *n_ident;
+        char *n_string;
         intmax_t n_integer;
     };
 };
@@ -40,6 +42,10 @@ static inline int integer_q(struct node *n) {
     return n && n->type == N_INTEGER;
 }
 
+static inline int string_q(struct node *n) {
+    return n && n->type == N_STRING;
+}
+
 static inline struct node *car(struct node *n) {
     assert(pair_q(n));
     return n->n_cons.car;
@@ -62,6 +68,7 @@ static inline struct node *cddr(struct node *n) {
     return cdr(cdr(n));
 }
 
+struct node *string_from_owned(char *ptr);
 struct node *cons(struct node *a, struct node *b);
 struct node *ident(const char *i);
 struct node *integer(intmax_t v);

compiler/include/unit.h

@@ -35,6 +35,7 @@ struct ext_unit {
 struct function {
     size_t index;
     size_t local_count;
+    size_t argc;
     struct node *args, *body;
     struct vector bytecode;
 };
@@ -47,6 +48,7 @@ struct export {
 struct unit {
     struct context global;
 
+    struct vector strtab;
     struct vector functions;
     struct vector exports;
     struct vector ext_refs;
@@ -59,5 +61,6 @@ struct function *unit_lambda(struct unit *u);
 int unit_ext_load(struct unit *self, const char *unit);
 int ctx_lookup_name(struct context *ctx, const char *name, int *kind, size_t *index);
 int unit_lookup_global(struct unit *unit, const char *name, size_t *index);
+int unit_insert_string(struct unit *unit, const char *text, size_t *index);
 
 void emit_insn(struct function *fn, uint32_t insn);

compiler/main.c

@@ -47,8 +47,10 @@ static void write_unit(FILE *fp, struct unit *u) {
     hdr.func_table_size = u->functions.size;
     for (size_t i = 0; i < u->functions.size; ++i) {
         struct function *fn = vector_ref(&u->functions, i);
-        offset += sizeof(struct bin_func_entry) + fn->bytecode.size;
+        offset += sizeof(struct bin_func_entry) + fn->bytecode.size * sizeof(uint32_t);
     }
+    hdr.string_table_offset = offset;
+    hdr.string_table_size = u->strtab.size;
 
     fwrite(&hdr, 1, sizeof(struct bin_header), fp);
     for (size_t i = 0; i < u->ext_units.size; ++i) {
@@ -77,16 +79,19 @@ static void write_unit(FILE *fp, struct unit *u) {
     for (size_t i = 0; i < u->functions.size; ++i) {
         struct function *fn = vector_ref(&u->functions, i);
         struct bin_func_entry bin_func;
-        size_t argc = 0;
+        bin_func.argc = fn->argc;
-        for (struct node *arg = fn->args; arg; arg = cdr(arg)) {
-            ++argc;
-        }
-        bin_func.argc = argc;
         bin_func.local_count = fn->local_count;
         bin_func.len = fn->bytecode.size * sizeof(uint32_t);
         fwrite(&bin_func, 1, sizeof(struct bin_func_entry), fp);
         fwrite(fn->bytecode.data, 1, fn->bytecode.size * sizeof(uint32_t), fp);
     }
+    for (size_t i = 0; i < u->strtab.size; ++i) {
+        char **ref = vector_ref(&u->strtab, i);
+        const char *str = *ref;
+        uint32_t len = strlen(str);
+        fwrite(&len, 1, sizeof(uint32_t), fp);
+        fwrite(str, 1, len + 1, fp);
+    }
 }
 
 int main(int argc, char **argv) {

compiler/node.c

@@ -5,6 +5,13 @@
 #include <stdlib.h>
 #include <stdio.h>
 
+struct node *string_from_owned(char *ptr) {
+    struct node *n = malloc(sizeof(struct node));
+    n->type = N_STRING;
+    n->n_string = ptr;
+    return n;
+}
+
 struct node *cons(struct node *a, struct node *b) {
     struct node *n = malloc(sizeof(struct node));
     n->type = N_CONS;
@@ -57,6 +64,9 @@ void vm_print(const struct node *node, int depth) {
     case N_INTEGER:
         printf("%zd", node->n_integer);
         break;
+    case N_STRING:
+        printf("\"%s\"", node->n_string);
+        break;
     case N_CONS:
         if (!depth) {
             printf("(");

compiler/parse.c

@@ -202,6 +202,39 @@ int vm_parse(struct vm_parser *in, struct node **out) {
         buf[i] = 0;
         *out = ident(buf);
         return 0;
+    } else if (ch == '"') {
+        char *buf;
+        size_t cap, len;
+        cap = 32;
+        len = 0;
+        buf = malloc(cap);
+        if (!buf) {
+            return -ENOMEM;
+        }
+
+        assert(in->pop(in) == ch);
+        while (1) {
+            ch = in->peek(in);
+            if (!ch) {
+                return -EINVAL;
+            }
+            assert(ch != '\\' && "Not implemented");
+            assert(in->pop(in) == ch);
+            if (ch == '"') {
+                break;
+            }
+
+            if (len == cap - 1) {
+                cap += 32;
+                buf = realloc(buf, cap);
+                assert(buf);
+            }
+
+            buf[len++] = ch;
+        }
+        buf[len] = 0;
+        *out = string_from_owned(buf);
+        return 0;
     }
 
     fprintf(stderr, "Unrecognized character: #%c (%d)\n", ch, ch);

compiler/unit.c

@@ -9,13 +9,17 @@
 #include <stdio.h>
 
 static struct ext_unit_entry u_core_entries[] = {
+    { "println" },
     { "print" },
-    { "file-open" },
+    { "putc" },
-    { "file-read" },
+
-    { "file-write" },
+    { "string-new" },
-    { "file-close" },
+    { "string-length" },
-    { "file-seek" },
+    { "string-ref" },
-    { "exit" }
+    { "string-set!" },
+    { "string-append" },
+
+    { "native" },
 };
 
 void unit_init(struct unit *u) {
@@ -27,6 +31,7 @@ void unit_init(struct unit *u) {
     vector_init(&u->ext_refs, sizeof(struct ext_ref));
     vector_init(&u->ext_units, sizeof(struct ext_unit));
     vector_init(&u->exports, sizeof(struct export));
+    vector_init(&u->strtab, sizeof(char *));
 }
 
 void ctx_init(struct context *ctx, struct context *parent) {
@@ -128,9 +133,13 @@ static int parse_exports(FILE *fp, struct ext_unit *unit) {
 int unit_ext_load(struct unit *self, const char *name) {
     if (!strcmp(name, "core")) {
         struct ext_unit *unit = vector_append(&self->ext_units);
-        unit->exports.size = sizeof(u_core_entries) / sizeof(u_core_entries[0]);
+        vector_init(&unit->exports, sizeof(struct ext_unit_entry));
-        unit->exports.cap = unit->exports.size;
+        for (size_t i = 0; i < sizeof(u_core_entries) / sizeof(u_core_entries[0]); ++i) {
-        unit->exports.data = u_core_entries;
+            struct ext_unit_entry *from, *to;
+            from = &u_core_entries[i];
+            to = vector_append(&unit->exports);
+            memcpy(to, from, sizeof(struct ext_unit_entry));
+        }
         strcpy(unit->name, name);
         return 0;
     }
@@ -148,6 +157,20 @@ int unit_ext_load(struct unit *self, const char *name) {
     return -ENOENT;
 }
 
+int unit_insert_string(struct unit *unit, const char *text, size_t *index) {
+    // TODO find identical strings?
+    *index = unit->strtab.size;
+    char **ref = vector_append(&unit->strtab);
+    if (!ref) {
+        return -ENOMEM;
+    }
+    *ref = strdup(text);
+    if (!*ref) {
+        return -ENOMEM;
+    }
+    return 0;
+}
+
 // TODO external references
 int ctx_lookup_name(struct context *ctx, const char *name, int *kind, size_t *index) {
     // 1. Lookup local

core/include/binary.h

@@ -16,6 +16,8 @@ struct bin_header {
     uint32_t export_table_size;
     uint32_t func_table_offset;
     uint32_t func_table_size;
+    uint32_t string_table_offset;
+    uint32_t string_table_size;
 };
 
 struct bin_unit_entry {

core/include/op.h

@@ -21,6 +21,7 @@
 #define OP_LDC          0x30
 #define OP_LDNIL        0x31
 #define OP_LDI          0x32
+#define OP_LDS          0x33
 
 #define OP_CAR          0x40
 #define OP_CDR          0x41

mod1.vml

@@ -1,15 +1,11 @@
 (use core)
 
-(define (f2 x)
+(define (string-chars s)
-  (define (f1 x y)
+  (define len (string-length s))
-    (define (f0 x y z)
+  (define out nil)
-      (+ x y z)
+  (while (/= len 0)
+    (setq len (- len 1))
+    (setq out (cons (string-ref s len) out))
   )
-
+  out
-    (f0 x y 1)
 )
-
-  (f1 x 2)
-)
-
-(print (f2 3))

vm/include/libcore.h

@@ -0,0 +1,4 @@
+#pragma once
+
+struct vm_unit_info;
+int load_core(struct vm_unit_info *info);

vm/include/unit.h

@@ -21,6 +21,7 @@ struct vm_func_entry {
 struct vm_unit {
     struct vector ref_table;
     struct vector functions;
+    struct vector strtab;
 
     uint64_t *global_pool;
     size_t global_pool_size;
@@ -28,6 +29,7 @@ struct vm_unit {
     int is_loaded;
 };
 
+char **unit_add_string(struct vm_unit *u);
 struct vm_func_entry *unit_add_function(struct vm_unit *u);
 struct vm_ref_entry *unit_add_ref(struct vm_unit *u);
 void unit_free(struct vm_unit *u);

vm/include/vmval.h

@@ -11,6 +11,7 @@ enum vm_type {
     VT_CONS,
     VT_STRING,
     VT_FUNC,
+    VT_CFUNC,
 };
 
 struct vm_value {
@@ -24,6 +25,7 @@ struct vm_value {
             size_t lib_index, fn_index;
         } v_func;
         struct vm_string v_string;
+        uintptr_t v_cfunc;
     };
 };
 
@@ -31,6 +33,10 @@ static inline int ref_q(uint64_t w) {
     return (w & FLAG_REF) != 0;
 }
 
+static inline int integer_q(uint64_t w) {
+    return !(w & FLAG_REF);
+}
+
 static inline int null_q(uint64_t w) {
     return w == FLAG_REF;
 }
@@ -40,6 +46,10 @@ static inline struct vm_value *getref(uint64_t w) {
     return (struct vm_value *) (w << 1);
 }
 
+static inline int string_q(uint64_t w) {
+    return !null_q(w) && ref_q(w) && getref(w)->type == VT_STRING;
+}
+
 static inline int cons_q(uint64_t w) {
     if (ref_q(w)) {
         return null_q(w) || getref(w)->type == VT_CONS;
@@ -52,6 +62,10 @@ static inline int func_q(uint64_t w) {
     return ref_q(w) && !null_q(w) && getref(w)->type == VT_FUNC;
 }
 
+static inline int cfunc_q(uint64_t w) {
+    return ref_q(w) && !null_q(w) && getref(w)->type == VT_CFUNC;
+}
+
 static inline int pair_q(uint64_t w) {
     return ref_q(w) && (!null_q(w) && getref(w)->type == VT_CONS);
 }
@@ -76,5 +90,6 @@ void vm_value_free(struct vm_value *val);
 struct vm_value *vm_cons(uint64_t w0, uint64_t w1);
 struct vm_value *vm_makestr(const char *str);
 struct vm_value *vm_func(size_t lib_index, size_t fn_index);
+struct vm_value *vm_cfunc(uintptr_t address);
 
 void vm_print(FILE *dst, uint64_t w);

vm/libcore.c

@@ -0,0 +1,137 @@
+#include "vmstate.h"
+#include "vmval.h"
+#include "error.h"
+#include "load.h"
+#include "unit.h"
+
+#include <string.h>
+
+#define ARG(name) \
+    uint64_t name; \
+    if ((res = vm_pop(vm, &name)) != 0) { \
+        return res; \
+    }
+#define ARG_INTEGER(name) \
+    int64_t name; \
+    if ((res = vm_pop_integer(vm, &name)) != 0) { \
+        return res; \
+    }
+
+// I/O stuff
+static int c_print(struct vm *vm) {
+    int res;
+    ARG(w);
+    if (string_q(w)) {
+        fputs(getref(w)->v_string.data, stdout);
+    } else {
+        vm_print(stdout, w);
+    }
+    vm_unref(w);
+    return 0;
+}
+
+static int c_println(struct vm *vm) {
+    int res;
+    if ((res = c_print(vm)) != 0) {
+        return res;
+    }
+    putc('\n', stdout);
+    return 0;
+}
+
+static int c_putc(struct vm *vm) {
+    int res;
+    ARG_INTEGER(c);
+    putc(c, stdout);
+    return 0;
+}
+
+// String stuff
+static int c_string_length(struct vm *vm) {
+    int res;
+    ARG(w);
+
+    if (!string_q(w)) {
+        return -ERR_OPERAND_TYPE;
+    }
+    struct vm_value *v = getref(w);
+    size_t len = vm_strlen(&v->v_string);
+    vm_value_unref(v);
+    return vm_push_integer(vm, len);
+}
+
+static int c_string_ref(struct vm *vm) {
+    int res;
+    ARG(s);
+    ARG_INTEGER(i);
+    if (!string_q(s)) {
+        return -ERR_OPERAND_TYPE;
+    }
+
+    struct vm_value *v = getref(s);
+    char c;
+    if (i < 0 || (size_t) i >= vm_strlen(&v->v_string)) {
+        vm_value_unref(v);
+        return -ERR_RANGE;
+    }
+    c = v->v_string.data[i];
+    vm_value_unref(v);
+    return vm_push_integer(vm, c);
+}
+
+static int c_extra_func(struct vm *vm) {
+    int res;
+    ARG(w);
+    printf("Runtime-resolved function was called!\n");
+    vm_unref(w);
+    return 0;
+}
+
+static int c_native(struct vm *vm) {
+    int res;
+    ARG(w);
+    if (!string_q(w)) {
+        return -ERR_OPERAND_TYPE;
+    }
+    struct vm_value *name = getref(w);
+    struct vm_value *sym;
+    if (!strcmp(name->v_string.data, "extra-func")) {
+        sym = vm_cfunc((uintptr_t) c_extra_func);
+    } else {
+        return -ERR_SYMBOL_UNDEFINED;
+    }
+    vm_value_unref(name);
+    vm_value_ref(sym);
+    vm_push_ref(vm, sym);
+    return 0;
+}
+
+static struct vm_export_entry c_unit_core_exports[] = {
+    { 1, { (uintptr_t) c_println }, "println" },
+    { 1, { (uintptr_t) c_print }, "print" },
+    { 1, { (uintptr_t) c_putc }, "putc" },
+
+    //{ 1, { (uintptr_t) c_string_length }, "string-new" },
+    { 1, { (uintptr_t) c_string_length }, "string-length" },
+    { 1, { (uintptr_t) c_string_ref }, "string-ref" },
+    //{ 1, { (uintptr_t) c_string_length }, "string-ref" },
+
+    { 1, { (uintptr_t) c_native }, "native" },
+};
+
+int load_core(struct vm_unit_info *info) {
+    struct vm_export_entry *ent;
+    assert(info);
+    vector_init(&info->exports, sizeof(struct vm_export_entry));
+    for (size_t i = 0; i < sizeof(c_unit_core_exports) / sizeof(struct vm_export_entry); ++i) {
+        ent = vector_append(&info->exports);
+        if (!ent) {
+            return -ERR_OUT_OF_MEMORY;
+        }
+        memcpy(ent, &c_unit_core_exports[i], sizeof(struct vm_export_entry));
+    }
+    info->unit = NULL;
+    info->index = 0xFFFFFFFF;
+    return 0;
+}
+

vm/load.c

@@ -10,41 +10,9 @@
 #include "load.h"
 #include "unit.h"
 #include "vmstate.h"
+#include "libcore.h"
 #include "vmval.h"
 
-static int c_print(struct vm *vm) {
-    uint64_t w;
-    int res;
-
-    if ((res = vm_pop(vm, &w)) != 0) {
-        return res;
-    }
-    vm_print(stdout, w);
-    printf("\n");
-    vm_unref(w);
-    return 0;
-}
-
-static struct vm_export_entry c_unit_core_exports[] = {
-    { 1, { (uintptr_t) c_print }, "print" }
-};
-
-static int load_core(struct vm_unit_info *info) {
-    struct vm_export_entry *ent;
-    assert(info);
-    vector_init(&info->exports, sizeof(struct vm_export_entry));
-    for (size_t i = 0; i < sizeof(c_unit_core_exports) / sizeof(struct vm_export_entry); ++i) {
-        ent = vector_append(&info->exports);
-        if (!ent) {
-            return -ERR_OUT_OF_MEMORY;
-        }
-        memcpy(ent, &c_unit_core_exports[i], sizeof(struct vm_export_entry));
-    }
-    info->unit = NULL;
-    info->index = 0xFFFFFFFF;
-    return 0;
-}
-
 static FILE *unit_try_open_in(const char *paths, const char *name) {
     const char *head;
     char path[256];
@@ -183,6 +151,28 @@ static int vm_load_refs(struct vm_unit *unit,
     return 0;
 }
 
+static int vm_load_strings(struct vm_unit *unit,
+                           struct bin_header *hdr,
+                           FILE *fp) {
+    uint32_t len;
+    fseek(fp, hdr->string_table_offset, SEEK_SET);
+    for (size_t i = 0; i < hdr->string_table_size; ++i) {
+        // TODO optimize this crap
+        char **ref = unit_add_string(unit);
+        if (!ref) {
+            return -ERR_OUT_OF_MEMORY;
+        }
+        fread(&len, 1, sizeof(uint32_t), fp);
+        *ref = malloc(len + 1);
+        if (!*ref) {
+            return -ERR_OUT_OF_MEMORY;
+        }
+        fread(*ref, 1, len + 1, fp);
+    }
+
+    return 0;
+}
+
 static int vm_load_exports(struct vm_unit_info *info,
                            struct bin_header *hdr,
                            FILE *fp) {
@@ -244,6 +234,10 @@ int vm_load_unit_file(struct vm *vm,
         }
     }
 
+    if ((res = vm_load_strings(unit, &hdr, fp)) != 0) {
+        return res;
+    }
+
     if (info) {
         info->unit = unit;
     }

vm/unit.c

@@ -12,6 +12,10 @@ struct vm_func_entry *unit_add_function(struct vm_unit *u) {
     return vector_append(&u->functions);
 }
 
+char **unit_add_string(struct vm_unit *u) {
+    return vector_append(&u->strtab);
+}
+
 void unit_free(struct vm_unit *u) {
     struct vm_func_entry *func;
 
@@ -21,6 +25,11 @@ void unit_free(struct vm_unit *u) {
         free(func->bytecode);
     }
     vector_free(&u->functions);
+    for (size_t i = 0; i < u->strtab.size; ++i) {
+        char **ref = vector_ref(&u->strtab, i);
+        free(*ref);
+    }
+    vector_free(&u->strtab);
 
     for (size_t i = 0; i < u->global_pool_size; ++i) {
         vm_unref(u->global_pool[i]);

vm/vmstate.c

@@ -95,6 +95,7 @@ struct vm_unit *vm_add_unit(struct vm *vm, size_t global_pool_size) {
 
     vector_init(&unit->ref_table, sizeof(struct vm_ref_entry));
     vector_init(&unit->functions, sizeof(struct vm_func_entry));
+    vector_init(&unit->strtab, sizeof(char *));
     return unit;
 }
 
@@ -152,10 +153,20 @@ static uint64_t *vm_arg_ref(struct vm *vm, size_t index) {
 }
 
 int vm_call_ref(struct vm *vm, struct vm_value *ref) {
-    if (ref->type != VT_FUNC) {
+    switch (ref->type) {
+    case VT_CFUNC:
+        {
+            int (*func) (struct vm *) = (void *) ref->v_cfunc;
+            if (!func) {
                 return -ERR_OPERAND_TYPE;
             }
+            return func(vm);
+        }
+    case VT_FUNC:
         return vm_call_unit_index(vm, ref->v_func.lib_index, ref->v_func.fn_index);
+    default:
+        return -ERR_OPERAND_TYPE;
+    }
 }
 
 static int vm_read_ext_ref(struct vm *vm, struct vm_ref_entry *ref, uint64_t *w) {
@@ -265,6 +276,21 @@ int vm_eval_step(struct vm *vm) {
         vm_unref(w0);
         vm_unref(w1);
         return res;
+    case OP_NEQ:
+        if ((res = stack_pop(&vm->data_stack, &w0)) != 0) {
+            return res;
+        }
+        if ((res = stack_pop(&vm->data_stack, &w1)) != 0) {
+            return res;
+        }
+        if (ref_q(w0) || ref_q(w1)) {
+            // TODO what do?
+            return -ERR_OPERAND_TYPE;
+        }
+        res = vm_push_bool(vm, w0 != w1);
+        vm_unref(w0);
+        vm_unref(w1);
+        return res;
 //
     case OP_LDNIL:
         return stack_push(&vm->data_stack, FLAG_REF);
@@ -345,6 +371,17 @@ int vm_eval_step(struct vm *vm) {
         v0 = vm_func(vm->lp, i0);
         vm_value_ref(v0);
         return vm_push_ref(vm, v0);
+    case OP_LDS:
+        i0 = opcode & 0xFFFFFF;
+        if (i0 >= unit->strtab.size) {
+            return -ERR_RANGE;
+        }
+        {
+            char **ref = vector_ref(&unit->strtab, i0);
+            v0 = vm_makestr(*ref);
+            vm_value_ref(v0);
+            return vm_push_ref(vm, v0);
+        }
     case OP_STL:
         i0 = opcode & 0xFFFFFF;
         if (i0 >= func->local_count) {
@@ -386,7 +423,7 @@ int vm_eval_step(struct vm *vm) {
             if ((res = vm_read_ext_ref(vm, r0, &w0)) != 0) {
                 return res;
             }
-            if (!func_q(w0)) {
+            if (!ref_q(w0) || null_q(w0)) {
                 return -ERR_OPERAND_TYPE;
             }
             return vm_call_ref(vm, getref(w0));
@@ -397,7 +434,7 @@ int vm_eval_step(struct vm *vm) {
             return -ERR_RANGE;
         }
         w0 = unit->global_pool[i0];
-        if (!func_q(w0)) {
+        if (!ref_q(w0) || null_q(w0)) {
             return -ERR_OPERAND_TYPE;
         }
         return vm_call_ref(vm, getref(w0));
@@ -405,7 +442,7 @@ int vm_eval_step(struct vm *vm) {
         if ((res = stack_pop(&vm->data_stack, &w0)) != 0) {
             return res;
         }
-        if (!func_q(w0)) {
+        if (!ref_q(w0) || null_q(w0)) {
             return -ERR_OPERAND_TYPE;
         }
         res = vm_call_ref(vm, getref(w0));

vm/vmval.c

@@ -34,6 +34,9 @@ static void vm_print_ref(FILE *fp, struct vm_value *value, int cdepth) {
             fprintf(fp, ")");
         }
         break;
+    case VT_CFUNC:
+        fprintf(fp, "<native function 0x%zx>", value->v_cfunc);
+        break;
     case VT_FUNC:
         fprintf(fp, "<function %zu:%zu>", value->v_func.lib_index, value->v_func.fn_index);
         break;
@@ -73,6 +76,7 @@ void vm_value_free(struct vm_value *v) {
         break;
     case VT_STRING:
         // TODO
+        break;
     default:
         break;
     }
@@ -100,6 +104,15 @@ int vm_value_unref(struct vm_value *v) {
     }
 }
 
+struct vm_value *vm_cfunc(uintptr_t ptr) {
+    struct vm_value *v = vm_value_create(VT_CFUNC);
+    if (!v) {
+        return NULL;
+    }
+    v->v_cfunc = ptr;
+    return v;
+}
+
 struct vm_value *vm_cons(uint64_t w0, uint64_t w1) {
     struct vm_value *v = vm_value_create(VT_CONS);
     if (!v) {