--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/luajit/src/lj_carith.c	Thu Jan 22 20:10:30 2026 -0800
@@ -0,0 +1,432 @@
+/*
+** C data arithmetic.
+** Copyright (C) 2005-2023 Mike Pall. See Copyright Notice in luajit.h
+*/
+
+#include "lj_obj.h"
+
+#if LJ_HASFFI
+
+#include "lj_gc.h"
+#include "lj_err.h"
+#include "lj_tab.h"
+#include "lj_meta.h"
+#include "lj_ir.h"
+#include "lj_ctype.h"
+#include "lj_cconv.h"
+#include "lj_cdata.h"
+#include "lj_carith.h"
+#include "lj_strscan.h"
+
+/* -- C data arithmetic --------------------------------------------------- */
+
+/* Binary operands of an operator converted to ctypes. */
+typedef struct CDArith {
+  uint8_t *p[2];
+  CType *ct[2];
+} CDArith;
+
+/* Check arguments for arithmetic metamethods. */
+static int carith_checkarg(lua_State *L, CTState *cts, CDArith *ca)
+{
+  TValue *o = L->base;
+  int ok = 1;
+  MSize i;
+  if (o+1 >= L->top)
+    lj_err_argt(L, 1, LUA_TCDATA);
+  for (i = 0; i < 2; i++, o++) {
+    if (tviscdata(o)) {
+      GCcdata *cd = cdataV(o);
+      CTypeID id = (CTypeID)cd->ctypeid;
+      CType *ct = ctype_raw(cts, id);
+      uint8_t *p = (uint8_t *)cdataptr(cd);
+      if (ctype_isptr(ct->info)) {
+	p = (uint8_t *)cdata_getptr(p, ct->size);
+	if (ctype_isref(ct->info)) ct = ctype_rawchild(cts, ct);
+      } else if (ctype_isfunc(ct->info)) {
+	p = (uint8_t *)*(void **)p;
+	ct = ctype_get(cts,
+	  lj_ctype_intern(cts, CTINFO(CT_PTR, CTALIGN_PTR|id), CTSIZE_PTR));
+      }
+      if (ctype_isenum(ct->info)) ct = ctype_child(cts, ct);
+      ca->ct[i] = ct;
+      ca->p[i] = p;
+    } else if (tvisint(o)) {
+      ca->ct[i] = ctype_get(cts, CTID_INT32);
+      ca->p[i] = (uint8_t *)&o->i;
+    } else if (tvisnum(o)) {
+      ca->ct[i] = ctype_get(cts, CTID_DOUBLE);
+      ca->p[i] = (uint8_t *)&o->n;
+    } else if (tvisnil(o)) {
+      ca->ct[i] = ctype_get(cts, CTID_P_VOID);
+      ca->p[i] = (uint8_t *)0;
+    } else if (tvisstr(o)) {
+      TValue *o2 = i == 0 ? o+1 : o-1;
+      CType *ct = ctype_raw(cts, cdataV(o2)->ctypeid);
+      ca->ct[i] = NULL;
+      ca->p[i] = (uint8_t *)strVdata(o);
+      ok = 0;
+      if (ctype_isenum(ct->info)) {
+	CTSize ofs;
+	CType *cct = lj_ctype_getfield(cts, ct, strV(o), &ofs);
+	if (cct && ctype_isconstval(cct->info)) {
+	  ca->ct[i] = ctype_child(cts, cct);
+	  ca->p[i] = (uint8_t *)&cct->size;  /* Assumes ct does not grow. */
+	  ok = 1;
+	} else {
+	  ca->ct[1-i] = ct;  /* Use enum to improve error message. */
+	  ca->p[1-i] = NULL;
+	  break;
+	}
+      }
+    } else {
+      ca->ct[i] = NULL;
+      ca->p[i] = (void *)(intptr_t)1;  /* To make it unequal. */
+      ok = 0;
+    }
+  }
+  return ok;
+}
+
+/* Pointer arithmetic. */
+static int carith_ptr(lua_State *L, CTState *cts, CDArith *ca, MMS mm)
+{
+  CType *ctp = ca->ct[0];
+  uint8_t *pp = ca->p[0];
+  ptrdiff_t idx;
+  CTSize sz;
+  CTypeID id;
+  GCcdata *cd;
+  if (ctype_isptr(ctp->info) || ctype_isrefarray(ctp->info)) {
+    if ((mm == MM_sub || mm == MM_eq || mm == MM_lt || mm == MM_le) &&
+	(ctype_isptr(ca->ct[1]->info) || ctype_isrefarray(ca->ct[1]->info))) {
+      uint8_t *pp2 = ca->p[1];
+      if (mm == MM_eq) {  /* Pointer equality. Incompatible pointers are ok. */
+	setboolV(L->top-1, (pp == pp2));
+	return 1;
+      }
+      if (!lj_cconv_compatptr(cts, ctp, ca->ct[1], CCF_IGNQUAL))
+	return 0;
+      if (mm == MM_sub) {  /* Pointer difference. */
+	intptr_t diff;
+	sz = lj_ctype_size(cts, ctype_cid(ctp->info));  /* Element size. */
+	if (sz == 0 || sz == CTSIZE_INVALID)
+	  return 0;
+	diff = ((intptr_t)pp - (intptr_t)pp2) / (int32_t)sz;
+	/* All valid pointer differences on x64 are in (-2^47, +2^47),
+	** which fits into a double without loss of precision.
+	*/
+	setintptrV(L->top-1, (int32_t)diff);
+	return 1;
+      } else if (mm == MM_lt) {  /* Pointer comparison (unsigned). */
+	setboolV(L->top-1, ((uintptr_t)pp < (uintptr_t)pp2));
+	return 1;
+      } else {
+	lj_assertL(mm == MM_le, "bad metamethod %d", mm);
+	setboolV(L->top-1, ((uintptr_t)pp <= (uintptr_t)pp2));
+	return 1;
+      }
+    }
+    if (!((mm == MM_add || mm == MM_sub) && ctype_isnum(ca->ct[1]->info)))
+      return 0;
+    lj_cconv_ct_ct(cts, ctype_get(cts, CTID_INT_PSZ), ca->ct[1],
+		   (uint8_t *)&idx, ca->p[1], 0);
+    if (mm == MM_sub) idx = -idx;
+  } else if (mm == MM_add && ctype_isnum(ctp->info) &&
+      (ctype_isptr(ca->ct[1]->info) || ctype_isrefarray(ca->ct[1]->info))) {
+    /* Swap pointer and index. */
+    ctp = ca->ct[1]; pp = ca->p[1];
+    lj_cconv_ct_ct(cts, ctype_get(cts, CTID_INT_PSZ), ca->ct[0],
+		   (uint8_t *)&idx, ca->p[0], 0);
+  } else {
+    return 0;
+  }
+  sz = lj_ctype_size(cts, ctype_cid(ctp->info));  /* Element size. */
+  if (sz == CTSIZE_INVALID)
+    return 0;
+  pp += idx*(int32_t)sz;  /* Compute pointer + index. */
+  id = lj_ctype_intern(cts, CTINFO(CT_PTR, CTALIGN_PTR|ctype_cid(ctp->info)),
+		       CTSIZE_PTR);
+  cd = lj_cdata_new(cts, id, CTSIZE_PTR);
+  *(uint8_t **)cdataptr(cd) = pp;
+  setcdataV(L, L->top-1, cd);
+  lj_gc_check(L);
+  return 1;
+}
+
+/* 64 bit integer arithmetic. */
+static int carith_int64(lua_State *L, CTState *cts, CDArith *ca, MMS mm)
+{
+  if (ctype_isnum(ca->ct[0]->info) && ca->ct[0]->size <= 8 &&
+      ctype_isnum(ca->ct[1]->info) && ca->ct[1]->size <= 8) {
+    CTypeID id = (((ca->ct[0]->info & CTF_UNSIGNED) && ca->ct[0]->size == 8) ||
+		  ((ca->ct[1]->info & CTF_UNSIGNED) && ca->ct[1]->size == 8)) ?
+		 CTID_UINT64 : CTID_INT64;
+    CType *ct = ctype_get(cts, id);
+    GCcdata *cd;
+    uint64_t u0, u1, *up;
+    lj_cconv_ct_ct(cts, ct, ca->ct[0], (uint8_t *)&u0, ca->p[0], 0);
+    if (mm != MM_unm)
+      lj_cconv_ct_ct(cts, ct, ca->ct[1], (uint8_t *)&u1, ca->p[1], 0);
+    switch (mm) {
+    case MM_eq:
+      setboolV(L->top-1, (u0 == u1));
+      return 1;
+    case MM_lt:
+      setboolV(L->top-1,
+	       id == CTID_INT64 ? ((int64_t)u0 < (int64_t)u1) : (u0 < u1));
+      return 1;
+    case MM_le:
+      setboolV(L->top-1,
+	       id == CTID_INT64 ? ((int64_t)u0 <= (int64_t)u1) : (u0 <= u1));
+      return 1;
+    default: break;
+    }
+    cd = lj_cdata_new(cts, id, 8);
+    up = (uint64_t *)cdataptr(cd);
+    setcdataV(L, L->top-1, cd);
+    switch (mm) {
+    case MM_add: *up = u0 + u1; break;
+    case MM_sub: *up = u0 - u1; break;
+    case MM_mul: *up = u0 * u1; break;
+    case MM_div:
+      if (id == CTID_INT64)
+	*up = (uint64_t)lj_carith_divi64((int64_t)u0, (int64_t)u1);
+      else
+	*up = lj_carith_divu64(u0, u1);
+      break;
+    case MM_mod:
+      if (id == CTID_INT64)
+	*up = (uint64_t)lj_carith_modi64((int64_t)u0, (int64_t)u1);
+      else
+	*up = lj_carith_modu64(u0, u1);
+      break;
+    case MM_pow:
+      if (id == CTID_INT64)
+	*up = (uint64_t)lj_carith_powi64((int64_t)u0, (int64_t)u1);
+      else
+	*up = lj_carith_powu64(u0, u1);
+      break;
+    case MM_unm: *up = ~u0+1u; break;
+    default:
+      lj_assertL(0, "bad metamethod %d", mm);
+      break;
+    }
+    lj_gc_check(L);
+    return 1;
+  }
+  return 0;
+}
+
+/* Handle ctype arithmetic metamethods. */
+static int lj_carith_meta(lua_State *L, CTState *cts, CDArith *ca, MMS mm)
+{
+  cTValue *tv = NULL;
+  if (tviscdata(L->base)) {
+    CTypeID id = cdataV(L->base)->ctypeid;
+    CType *ct = ctype_raw(cts, id);
+    if (ctype_isptr(ct->info)) id = ctype_cid(ct->info);
+    tv = lj_ctype_meta(cts, id, mm);
+  }
+  if (!tv && L->base+1 < L->top && tviscdata(L->base+1)) {
+    CTypeID id = cdataV(L->base+1)->ctypeid;
+    CType *ct = ctype_raw(cts, id);
+    if (ctype_isptr(ct->info)) id = ctype_cid(ct->info);
+    tv = lj_ctype_meta(cts, id, mm);
+  }
+  if (!tv) {
+    const char *repr[2];
+    int i, isenum = -1, isstr = -1;
+    if (mm == MM_eq) {  /* Equality checks never raise an error. */
+      int eq = ca->p[0] == ca->p[1];
+      setboolV(L->top-1, eq);
+      setboolV(&G(L)->tmptv2, eq);  /* Remember for trace recorder. */
+      return 1;
+    }
+    for (i = 0; i < 2; i++) {
+      if (ca->ct[i] && tviscdata(L->base+i)) {
+	if (ctype_isenum(ca->ct[i]->info)) isenum = i;
+	repr[i] = strdata(lj_ctype_repr(L, ctype_typeid(cts, ca->ct[i]), NULL));
+      } else {
+	if (tvisstr(&L->base[i])) isstr = i;
+	repr[i] = lj_typename(&L->base[i]);
+      }
+    }
+    if ((isenum ^ isstr) == 1)
+      lj_err_callerv(L, LJ_ERR_FFI_BADCONV, repr[isstr], repr[isenum]);
+    lj_err_callerv(L, mm == MM_len ? LJ_ERR_FFI_BADLEN :
+		      mm == MM_concat ? LJ_ERR_FFI_BADCONCAT :
+		      mm < MM_add ? LJ_ERR_FFI_BADCOMP : LJ_ERR_FFI_BADARITH,
+		   repr[0], repr[1]);
+  }
+  return lj_meta_tailcall(L, tv);
+}
+
+/* Arithmetic operators for cdata. */
+int lj_carith_op(lua_State *L, MMS mm)
+{
+  CTState *cts = ctype_cts(L);
+  CDArith ca;
+  if (carith_checkarg(L, cts, &ca) && mm != MM_len && mm != MM_concat) {
+    if (carith_int64(L, cts, &ca, mm) || carith_ptr(L, cts, &ca, mm)) {
+      copyTV(L, &G(L)->tmptv2, L->top-1);  /* Remember for trace recorder. */
+      return 1;
+    }
+  }
+  return lj_carith_meta(L, cts, &ca, mm);
+}
+
+/* -- 64 bit bit operations helpers --------------------------------------- */
+
+#if LJ_64
+#define B64DEF(name) \
+  static LJ_AINLINE uint64_t lj_carith_##name(uint64_t x, int32_t sh)
+#else
+/* Not inlined on 32 bit archs, since some of these are quite lengthy. */
+#define B64DEF(name) \
+  uint64_t LJ_NOINLINE lj_carith_##name(uint64_t x, int32_t sh)
+#endif
+
+B64DEF(shl64) { return x << (sh&63); }
+B64DEF(shr64) { return x >> (sh&63); }
+B64DEF(sar64) { return (uint64_t)((int64_t)x >> (sh&63)); }
+B64DEF(rol64) { return lj_rol(x, (sh&63)); }
+B64DEF(ror64) { return lj_ror(x, (sh&63)); }
+
+#undef B64DEF
+
+uint64_t lj_carith_shift64(uint64_t x, int32_t sh, int op)
+{
+  switch (op) {
+  case IR_BSHL-IR_BSHL: x = lj_carith_shl64(x, sh); break;
+  case IR_BSHR-IR_BSHL: x = lj_carith_shr64(x, sh); break;
+  case IR_BSAR-IR_BSHL: x = lj_carith_sar64(x, sh); break;
+  case IR_BROL-IR_BSHL: x = lj_carith_rol64(x, sh); break;
+  case IR_BROR-IR_BSHL: x = lj_carith_ror64(x, sh); break;
+  default:
+    lj_assertX(0, "bad shift op %d", op);
+    break;
+  }
+  return x;
+}
+
+/* Equivalent to lj_lib_checkbit(), but handles cdata. */
+uint64_t lj_carith_check64(lua_State *L, int narg, CTypeID *id)
+{
+  TValue *o = L->base + narg-1;
+  if (o >= L->top) {
+  err:
+    lj_err_argt(L, narg, LUA_TNUMBER);
+  } else if (LJ_LIKELY(tvisnumber(o))) {
+    /* Handled below. */
+  } else if (tviscdata(o)) {
+    CTState *cts = ctype_cts(L);
+    uint8_t *sp = (uint8_t *)cdataptr(cdataV(o));
+    CTypeID sid = cdataV(o)->ctypeid;
+    CType *s = ctype_get(cts, sid);
+    uint64_t x;
+    if (ctype_isref(s->info)) {
+      sp = *(void **)sp;
+      sid = ctype_cid(s->info);
+    }
+    s = ctype_raw(cts, sid);
+    if (ctype_isenum(s->info)) s = ctype_child(cts, s);
+    if ((s->info & (CTMASK_NUM|CTF_BOOL|CTF_FP|CTF_UNSIGNED)) ==
+	CTINFO(CT_NUM, CTF_UNSIGNED) && s->size == 8)
+      *id = CTID_UINT64;  /* Use uint64_t, since it has the highest rank. */
+    else if (!*id)
+      *id = CTID_INT64;  /* Use int64_t, unless already set. */
+    lj_cconv_ct_ct(cts, ctype_get(cts, *id), s,
+		   (uint8_t *)&x, sp, CCF_ARG(narg));
+    return x;
+  } else if (!(tvisstr(o) && lj_strscan_number(strV(o), o))) {
+    goto err;
+  }
+  if (LJ_LIKELY(tvisint(o))) {
+    return (uint32_t)intV(o);
+  } else {
+    int32_t i = lj_num2bit(numV(o));
+    if (LJ_DUALNUM) setintV(o, i);
+    return (uint32_t)i;
+  }
+}
+
+/* -- 64 bit integer arithmetic helpers ----------------------------------- */
+
+#if LJ_32 && LJ_HASJIT
+/* Signed/unsigned 64 bit multiplication. */
+int64_t lj_carith_mul64(int64_t a, int64_t b)
+{
+  return a * b;
+}
+#endif
+
+/* Unsigned 64 bit division. */
+uint64_t lj_carith_divu64(uint64_t a, uint64_t b)
+{
+  if (b == 0) return U64x(80000000,00000000);
+  return a / b;
+}
+
+/* Signed 64 bit division. */
+int64_t lj_carith_divi64(int64_t a, int64_t b)
+{
+  if (b == 0 || (a == (int64_t)U64x(80000000,00000000) && b == -1))
+    return U64x(80000000,00000000);
+  return a / b;
+}
+
+/* Unsigned 64 bit modulo. */
+uint64_t lj_carith_modu64(uint64_t a, uint64_t b)
+{
+  if (b == 0) return U64x(80000000,00000000);
+  return a % b;
+}
+
+/* Signed 64 bit modulo. */
+int64_t lj_carith_modi64(int64_t a, int64_t b)
+{
+  if (b == 0) return U64x(80000000,00000000);
+  if (a == (int64_t)U64x(80000000,00000000) && b == -1) return 0;
+  return a % b;
+}
+
+/* Unsigned 64 bit x^k. */
+uint64_t lj_carith_powu64(uint64_t x, uint64_t k)
+{
+  uint64_t y;
+  if (k == 0)
+    return 1;
+  for (; (k & 1) == 0; k >>= 1) x *= x;
+  y = x;
+  if ((k >>= 1) != 0) {
+    for (;;) {
+      x *= x;
+      if (k == 1) break;
+      if (k & 1) y *= x;
+      k >>= 1;
+    }
+    y *= x;
+  }
+  return y;
+}
+
+/* Signed 64 bit x^k. */
+int64_t lj_carith_powi64(int64_t x, int64_t k)
+{
+  if (k == 0)
+    return 1;
+  if (k < 0) {
+    if (x == 0)
+      return U64x(7fffffff,ffffffff);
+    else if (x == 1)
+      return 1;
+    else if (x == -1)
+      return (k & 1) ? -1 : 1;
+    else
+      return 0;
+  }
+  return (int64_t)lj_carith_powu64((uint64_t)x, (uint64_t)k);
+}
+
+#endif