mirror of
https://github.com/LuaJIT/LuaJIT.git
synced 2025-02-07 23:24:09 +00:00
261 lines
7.2 KiB
C
261 lines
7.2 KiB
C
/*
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** C data arithmetic.
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** Copyright (C) 2005-2011 Mike Pall. See Copyright Notice in luajit.h
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*/
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#include "lj_obj.h"
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#if LJ_HASFFI
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#include "lj_gc.h"
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#include "lj_err.h"
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#include "lj_ctype.h"
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#include "lj_cconv.h"
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#include "lj_cdata.h"
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#include "lj_carith.h"
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/* -- C data arithmetic --------------------------------------------------- */
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/* Binary operands of an operator converted to ctypes. */
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typedef struct CDArith {
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uint8_t *p[2];
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CType *ct[2];
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} CDArith;
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/* Check arguments for arithmetic metamethods. */
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static int carith_checkarg(lua_State *L, CTState *cts, CDArith *ca)
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{
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TValue *o = L->base;
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int ok = 1;
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MSize i;
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if (o+1 >= L->top)
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lj_err_argt(L, 1, LUA_TCDATA);
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for (i = 0; i < 2; i++, o++) {
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if (tviscdata(o)) {
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GCcdata *cd = cdataV(o);
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CType *ct = ctype_raw(cts, (CTypeID)cd->typeid);
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uint8_t *p = (uint8_t *)cdataptr(cd);
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if (ctype_isptr(ct->info)) {
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p = (uint8_t *)cdata_getptr(p, ct->size);
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if (ctype_isref(ct->info)) ct = ctype_rawchild(cts, ct);
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}
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ca->ct[i] = ct;
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ca->p[i] = p;
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} else if (tvisnum(o)) {
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ca->ct[i] = ctype_get(cts, CTID_DOUBLE);
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ca->p[i] = (uint8_t *)&o->n;
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} else if (tvisnil(o)) {
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ca->ct[i] = ctype_get(cts, CTID_P_VOID);
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ca->p[i] = (uint8_t *)0;
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} else {
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ca->ct[i] = NULL;
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ca->p[i] = NULL;
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ok = 0;
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}
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}
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return ok;
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}
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/* Pointer arithmetic. */
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static int carith_ptr(lua_State *L, CTState *cts, CDArith *ca, MMS mm)
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{
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CType *ctp = ca->ct[0];
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uint8_t *pp = ca->p[0];
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ptrdiff_t idx;
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CTSize sz;
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CTypeID id;
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GCcdata *cd;
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if (ctype_isptr(ctp->info) || ctype_isrefarray(ctp->info)) {
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if ((mm == MM_sub || mm == MM_eq || mm == MM_lt || mm == MM_le) &&
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(ctype_isptr(ca->ct[1]->info) || ctype_isrefarray(ca->ct[1]->info))) {
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uint8_t *pp2 = ca->p[1];
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if (mm == MM_eq) { /* Pointer equality. Incompatible pointers are ok. */
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setboolV(L->top-1, (pp == pp2));
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return 1;
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}
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if (!lj_cconv_compatptr(cts, ctp, ca->ct[1], CCF_IGNQUAL))
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return 0;
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if (mm == MM_sub) { /* Pointer difference. */
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intptr_t diff;
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sz = lj_ctype_size(cts, ctype_cid(ctp->info)); /* Element size. */
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if (sz == 0 || sz == CTSIZE_INVALID)
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return 0;
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diff = ((intptr_t)pp - (intptr_t)pp2) / (int32_t)sz;
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/* All valid pointer differences on x64 are in (-2^47, +2^47),
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** which fits into a double without loss of precision.
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*/
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setnumV(L->top-1, (lua_Number)diff);
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return 1;
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} else if (mm == MM_lt) { /* Pointer comparison (unsigned). */
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setboolV(L->top-1, ((uintptr_t)pp < (uintptr_t)pp2));
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return 1;
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} else {
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lua_assert(mm == MM_le);
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setboolV(L->top-1, ((uintptr_t)pp <= (uintptr_t)pp2));
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return 1;
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}
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}
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if (!((mm == MM_add || mm == MM_sub) && ctype_isnum(ca->ct[1]->info)))
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return 0;
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lj_cconv_ct_ct(cts, ctype_get(cts, CTID_INT_PSZ), ca->ct[1],
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(uint8_t *)&idx, ca->p[1], 0);
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if (mm == MM_sub) idx = -idx;
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} else if (mm == MM_add && ctype_isnum(ctp->info) &&
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(ctype_isptr(ca->ct[1]->info) || ctype_isrefarray(ca->ct[1]->info))) {
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/* Swap pointer and index. */
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ctp = ca->ct[1]; pp = ca->p[1];
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lj_cconv_ct_ct(cts, ctype_get(cts, CTID_INT_PSZ), ca->ct[0],
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(uint8_t *)&idx, ca->p[0], 0);
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} else {
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return 0;
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}
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sz = lj_ctype_size(cts, ctype_cid(ctp->info)); /* Element size. */
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if (sz == CTSIZE_INVALID)
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return 0;
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pp += idx*(int32_t)sz; /* Compute pointer + index. */
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id = lj_ctype_intern(cts, CTINFO(CT_PTR, CTALIGN_PTR|ctype_cid(ctp->info)),
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CTSIZE_PTR);
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cd = lj_cdata_new(cts, id, CTSIZE_PTR);
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*(uint8_t **)cdataptr(cd) = pp;
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setcdataV(L, L->top-1, cd);
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lj_gc_check(L);
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return 1;
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}
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/* 64 bit integer arithmetic. */
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static int carith_int64(lua_State *L, CTState *cts, CDArith *ca, MMS mm)
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{
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if (ctype_isnum(ca->ct[0]->info) && ca->ct[0]->size <= 8 &&
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ctype_isnum(ca->ct[1]->info) && ca->ct[1]->size <= 8) {
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CTypeID id = (((ca->ct[0]->info & CTF_UNSIGNED) && ca->ct[0]->size == 8) ||
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((ca->ct[1]->info & CTF_UNSIGNED) && ca->ct[1]->size == 8)) ?
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CTID_UINT64 : CTID_INT64;
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CType *ct = ctype_get(cts, id);
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GCcdata *cd;
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uint64_t u0, u1, *up;
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lj_cconv_ct_ct(cts, ct, ca->ct[0], (uint8_t *)&u0, ca->p[0], 0);
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if (mm != MM_unm)
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lj_cconv_ct_ct(cts, ct, ca->ct[1], (uint8_t *)&u1, ca->p[1], 0);
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switch (mm) {
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case MM_eq:
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setboolV(L->top-1, (u0 == u1));
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return 1;
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case MM_lt:
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setboolV(L->top-1,
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id == CTID_INT64 ? ((int64_t)u0 < (int64_t)u1) : (u0 < u1));
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return 1;
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case MM_le:
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setboolV(L->top-1,
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id == CTID_INT64 ? ((int64_t)u0 <= (int64_t)u1) : (u0 <= u1));
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return 1;
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case MM_div: case MM_mod:
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if (u1 == 0) { /* Division by zero. */
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if (u0 == 0)
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setnanV(L->top-1);
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else if (id == CTID_INT64 && (int64_t)u0 < 0)
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setminfV(L->top-1);
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else
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setpinfV(L->top-1);
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return 1;
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} else if (id == CTID_INT64 && (int64_t)u1 == -1 &&
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u0 == U64x(80000000,00000000)) { /* MIN64 / -1. */
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if (mm == MM_div) id = CTID_UINT64; else u0 = 0;
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mm = MM_unm; /* Result is 0x8000000000000000ULL or 0LL. */
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}
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break;
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default: break;
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}
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cd = lj_cdata_new(cts, id, 8);
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up = (uint64_t *)cdataptr(cd);
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setcdataV(L, L->top-1, cd);
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switch (mm) {
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case MM_add: *up = u0 + u1; break;
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case MM_sub: *up = u0 - u1; break;
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case MM_mul: *up = u0 * u1; break;
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case MM_div:
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if (id == CTID_INT64)
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*up = (uint64_t)((int64_t)u0 / (int64_t)u1);
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else
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*up = u0 / u1;
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break;
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case MM_mod:
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if (id == CTID_INT64)
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*up = (uint64_t)((int64_t)u0 % (int64_t)u1);
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else
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*up = u0 % u1;
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break;
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case MM_pow: *up = lj_carith_powi64(u0, u1, (id == CTID_UINT64)); break;
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case MM_unm: *up = (uint64_t)-(int64_t)u0; break;
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default: lua_assert(0); break;
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}
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lj_gc_check(L);
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return 1;
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}
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return 0;
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}
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/* Arithmetic operators for cdata. */
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int lj_carith_op(lua_State *L, MMS mm)
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{
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CTState *cts = ctype_cts(L);
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CDArith ca;
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if (carith_checkarg(L, cts, &ca)) {
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if (carith_int64(L, cts, &ca, mm) || carith_ptr(L, cts, &ca, mm)) {
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copyTV(L, &G(L)->tmptv2, L->top-1); /* Remember for trace recorder. */
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return 1;
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}
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}
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/* NYI: per-cdata metamethods. */
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{
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const char *repr[2];
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int i;
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for (i = 0; i < 2; i++) {
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if (ca.ct[i])
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repr[i] = strdata(lj_ctype_repr(L, ctype_typeid(cts, ca.ct[i]), NULL));
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else
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repr[i] = typename(&L->base[i]);
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}
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lj_err_callerv(L, mm == MM_len ? LJ_ERR_FFI_BADLEN :
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mm == MM_concat ? LJ_ERR_FFI_BADCONCAT :
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mm < MM_add ? LJ_ERR_FFI_BADCOMP : LJ_ERR_FFI_BADARITH,
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repr[0], repr[1]);
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}
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return 0; /* unreachable */
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}
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/* -- 64 bit integer arithmetic helpers ----------------------------------- */
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/* 64 bit integer x^k. */
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uint64_t lj_carith_powi64(uint64_t x, uint64_t k, int isunsigned)
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{
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uint64_t y = 0;
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if (k == 0)
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return 1;
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if (!isunsigned) {
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if ((int64_t)k < 0) {
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if (x == 0)
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return U64x(7fffffff,ffffffff);
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else if (x == 1)
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return 1;
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else if ((int64_t)x == -1)
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return (k & 1) ? -1 : 1;
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else
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return 0;
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}
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}
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for (; (k & 1) == 0; k >>= 1) x *= x;
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y = x;
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if ((k >>= 1) != 0) {
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for (;;) {
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x *= x;
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if (k == 1) break;
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if (k & 1) y *= x;
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k >>= 1;
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}
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y *= x;
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}
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return y;
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}
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#endif
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