cell/qbe_rt.c

/*
 * qbe_rt.c - Runtime support for QBE-compiled ƿit modules
 *
 * Provides non-inline versions of static-inline quickjs functions
 * (which QBE-generated code calls as external symbols) and stub
 * implementations of cell_rt_* helper functions.
 */

#include <stdint.h>
#include <string.h>
#include <math.h>

typedef uint64_t JSValue;
typedef struct JSContext JSContext;

#define JS_TAG_SHORT_FLOAT 5
#define JS_TAG_NULL        7
#define JS_VAL_NULL        7

/* ============================================================
   Non-inline wrappers for static-inline quickjs functions
   ============================================================ */

/*
 * __JS_NewFloat64 — encode double as tagged JSValue
 * Short float: [sign:1][exp:8][mantissa:52][tag:3]
 * Returns tagged int if value is an exact integer in int32 range
 */
JSValue __JS_NewFloat64(JSContext *ctx, double d) {
  union { double d; uint64_t u; } u;
  u.d = d;

  uint64_t sign = u.u >> 63;
  int exp = (u.u >> 52) & 0x7FF;
  uint64_t mantissa = u.u & ((1ULL << 52) - 1);

  /* Zero */
  if (exp == 0 && mantissa == 0)
    return JS_TAG_SHORT_FLOAT;
  /* NaN/Inf → null */
  if (exp == 0x7FF)
    return JS_VAL_NULL;
  /* Subnormals → zero */
  if (exp == 0)
    return (sign << 63) | JS_TAG_SHORT_FLOAT;

  int short_exp = exp - 1023 + 127;
  if (short_exp < 1 || short_exp > 254)
    return JS_VAL_NULL;

  /* Prefer integer if exact */
  if (d >= (double)(-2147483647 - 1) && d <= (double)2147483647) {
    int32_t i = (int32_t)d;
    if ((double)i == d)
      return (uint64_t)(uint32_t)i << 1;
  }

  return (sign << 63)
       | ((uint64_t)short_exp << 55)
       | (mantissa << 3)
       | JS_TAG_SHORT_FLOAT;
}

/*
 * JS_IsNumber — check if value is tagged int or short float
 */
int JS_IsNumber(JSValue v) {
  int is_int = (v & 1) == 0;
  int is_float = (v & 7) == JS_TAG_SHORT_FLOAT;
  return is_int || is_float;
}

/*
 * JS_NewString — create string from C string (wraps JS_NewStringLen)
 */
extern JSValue JS_NewStringLen(JSContext *ctx, const char *str, size_t len);

JSValue JS_NewString(JSContext *ctx, const char *str) {
  return JS_NewStringLen(ctx, str, strlen(str));
}

/* ============================================================
   cell_rt_* stubs — error/fallback paths for QBE-compiled code
   These are called from type-mismatch branches that should not
   be reached in pure numeric code.
   ============================================================ */

extern JSValue JS_ThrowTypeError(JSContext *ctx, const char *fmt, ...);

void cell_rt_disrupt(JSContext *ctx) {
  JS_ThrowTypeError(ctx, "type error in native code");
}

JSValue cell_rt_lt_text(JSContext *ctx, JSValue a, JSValue b) {
  return JS_VAL_NULL;
}
JSValue cell_rt_gt_text(JSContext *ctx, JSValue a, JSValue b) {
  return JS_VAL_NULL;
}
JSValue cell_rt_le_text(JSContext *ctx, JSValue a, JSValue b) {
  return JS_VAL_NULL;
}
JSValue cell_rt_ge_text(JSContext *ctx, JSValue a, JSValue b) {
  return JS_VAL_NULL;
}
JSValue cell_rt_eq_tol(JSContext *ctx, JSValue a, JSValue b) {
  return JS_VAL_NULL;
}
JSValue cell_rt_ne_tol(JSContext *ctx, JSValue a, JSValue b) {
  return JS_VAL_NULL;
}

JSValue cell_rt_get_intrinsic(JSContext *ctx, const char *name) {
  return JS_VAL_NULL;
}
JSValue cell_rt_load_field(JSContext *ctx, JSValue obj, const char *name) {
  return JS_VAL_NULL;
}
JSValue cell_rt_load_dynamic(JSContext *ctx, JSValue obj, JSValue key) {
  return JS_VAL_NULL;
}
JSValue cell_rt_load_index(JSContext *ctx, JSValue arr, JSValue idx) {
  return JS_VAL_NULL;
}
void cell_rt_store_field(JSContext *ctx, JSValue val, JSValue obj,
                         const char *name) {}
void cell_rt_store_dynamic(JSContext *ctx, JSValue val, JSValue obj,
                           JSValue key) {}
void cell_rt_store_index(JSContext *ctx, JSValue val, JSValue arr,
                         JSValue idx) {}
JSValue cell_rt_get_closure(JSContext *ctx, void *fp, int64_t depth,
                            int64_t index) {
  return JS_VAL_NULL;
}
void cell_rt_put_closure(JSContext *ctx, void *fp, JSValue val, int64_t depth,
                         int64_t index) {}
JSValue cell_rt_frame(JSContext *ctx, JSValue fn, int64_t nargs) {
  return JS_VAL_NULL;
}
void cell_rt_setarg(JSValue frame, int64_t idx, JSValue val) {}
JSValue cell_rt_invoke(JSContext *ctx, JSValue frame) { return JS_VAL_NULL; }
JSValue cell_rt_goframe(JSContext *ctx, JSValue fn, int64_t nargs) {
  return JS_VAL_NULL;
}
void cell_rt_goinvoke(JSContext *ctx, JSValue frame) {}
JSValue cell_rt_make_function(JSContext *ctx, int64_t fn_idx) {
  return JS_VAL_NULL;
}
void cell_rt_push(JSContext *ctx, JSValue arr, JSValue val) {}
JSValue cell_rt_pop(JSContext *ctx, JSValue arr) { return JS_VAL_NULL; }
JSValue cell_rt_delete(JSContext *ctx, JSValue obj, JSValue key) {
  return JS_VAL_NULL;
}
JSValue cell_rt_typeof(JSContext *ctx, JSValue val) { return JS_VAL_NULL; }