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343 lines
8.7 KiB
343 lines
8.7 KiB
/*
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* IEEE double helpers.
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*/
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#include "duk_internal.h"
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DUK_INTERNAL duk_bool_t duk_double_is_anyinf(duk_double_t x) {
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duk_double_union du;
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du.d = x;
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return DUK_DBLUNION_IS_ANYINF(&du);
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}
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DUK_INTERNAL duk_bool_t duk_double_is_posinf(duk_double_t x) {
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duk_double_union du;
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du.d = x;
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return DUK_DBLUNION_IS_POSINF(&du);
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}
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DUK_INTERNAL duk_bool_t duk_double_is_neginf(duk_double_t x) {
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duk_double_union du;
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du.d = x;
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return DUK_DBLUNION_IS_NEGINF(&du);
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}
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DUK_INTERNAL duk_bool_t duk_double_is_nan(duk_double_t x) {
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duk_double_union du;
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du.d = x;
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/* Assumes we're dealing with a Duktape internal NaN which is
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* NaN normalized if duk_tval requires it.
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*/
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DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&du));
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return DUK_DBLUNION_IS_NAN(&du);
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}
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DUK_INTERNAL duk_bool_t duk_double_is_nan_or_zero(duk_double_t x) {
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duk_double_union du;
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du.d = x;
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/* Assumes we're dealing with a Duktape internal NaN which is
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* NaN normalized if duk_tval requires it.
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*/
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DUK_ASSERT(DUK_DBLUNION_IS_NORMALIZED(&du));
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return DUK_DBLUNION_IS_NAN(&du) || DUK_DBLUNION_IS_ANYZERO(&du);
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}
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DUK_INTERNAL duk_bool_t duk_double_is_nan_or_inf(duk_double_t x) {
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duk_double_union du;
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du.d = x;
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/* If exponent is 0x7FF the argument is either a NaN or an
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* infinity. We don't need to check any other fields.
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*/
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#if defined(DUK_USE_64BIT_OPS)
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#if defined(DUK_USE_DOUBLE_ME)
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return (du.ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x000000007ff00000)) == DUK_U64_CONSTANT(0x000000007ff00000);
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#else
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return (du.ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x7ff0000000000000)) == DUK_U64_CONSTANT(0x7ff0000000000000);
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#endif
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#else
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return (du.ui[DUK_DBL_IDX_UI0] & 0x7ff00000UL) == 0x7ff00000UL;
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#endif
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}
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DUK_INTERNAL duk_bool_t duk_double_is_nan_zero_inf(duk_double_t x) {
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duk_double_union du;
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#if defined(DUK_USE_64BIT_OPS)
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duk_uint64_t t;
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#else
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duk_uint32_t t;
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#endif
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du.d = x;
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#if defined(DUK_USE_64BIT_OPS)
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#if defined(DUK_USE_DOUBLE_ME)
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t = du.ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x000000007ff00000);
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if (t == DUK_U64_CONSTANT(0x0000000000000000)) {
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t = du.ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x0000000080000000);
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return t == 0;
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}
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if (t == DUK_U64_CONSTANT(0x000000007ff00000)) {
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return 1;
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}
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#else
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t = du.ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x7ff0000000000000);
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if (t == DUK_U64_CONSTANT(0x0000000000000000)) {
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t = du.ull[DUK_DBL_IDX_ULL0] & DUK_U64_CONSTANT(0x8000000000000000);
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return t == 0;
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}
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if (t == DUK_U64_CONSTANT(0x7ff0000000000000)) {
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return 1;
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}
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#endif
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#else
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t = du.ui[DUK_DBL_IDX_UI0] & 0x7ff00000UL;
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if (t == 0x00000000UL) {
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return DUK_DBLUNION_IS_ANYZERO(&du);
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}
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if (t == 0x7ff00000UL) {
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return 1;
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}
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#endif
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return 0;
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}
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DUK_INTERNAL duk_small_uint_t duk_double_signbit(duk_double_t x) {
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duk_double_union du;
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du.d = x;
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return (duk_small_uint_t) DUK_DBLUNION_GET_SIGNBIT(&du);
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}
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DUK_INTERNAL duk_double_t duk_double_trunc_towards_zero(duk_double_t x) {
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/* XXX: optimize */
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duk_small_uint_t s = duk_double_signbit(x);
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x = DUK_FLOOR(DUK_FABS(x)); /* truncate towards zero */
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if (s) {
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x = -x;
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}
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return x;
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}
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DUK_INTERNAL duk_bool_t duk_double_same_sign(duk_double_t x, duk_double_t y) {
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duk_double_union du1;
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duk_double_union du2;
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du1.d = x;
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du2.d = y;
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return (((du1.ui[DUK_DBL_IDX_UI0] ^ du2.ui[DUK_DBL_IDX_UI0]) & 0x80000000UL) == 0);
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}
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DUK_INTERNAL duk_double_t duk_double_fmin(duk_double_t x, duk_double_t y) {
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/* Doesn't replicate fmin() behavior exactly: for fmin() if one
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* argument is a NaN, the other argument should be returned.
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* Duktape doesn't rely on this behavior so the replacement can
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* be simplified.
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*/
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return (x < y ? x : y);
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}
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DUK_INTERNAL duk_double_t duk_double_fmax(duk_double_t x, duk_double_t y) {
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/* Doesn't replicate fmax() behavior exactly: for fmax() if one
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* argument is a NaN, the other argument should be returned.
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* Duktape doesn't rely on this behavior so the replacement can
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* be simplified.
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*/
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return (x > y ? x : y);
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}
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DUK_INTERNAL duk_bool_t duk_double_is_finite(duk_double_t x) {
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return !duk_double_is_nan_or_inf(x);
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}
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DUK_INTERNAL duk_bool_t duk_double_is_integer(duk_double_t x) {
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if (duk_double_is_nan_or_inf(x)) {
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return 0;
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} else {
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return duk_double_equals(duk_js_tointeger_number(x), x);
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}
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}
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DUK_INTERNAL duk_bool_t duk_double_is_safe_integer(duk_double_t x) {
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/* >>> 2**53-1
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* 9007199254740991
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*/
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return duk_double_is_integer(x) && DUK_FABS(x) <= 9007199254740991.0;
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}
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/* Check whether a duk_double_t is a whole number in the 32-bit range (reject
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* negative zero), and if so, return a duk_int32_t.
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* For compiler use: don't allow negative zero as it will cause trouble with
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* LDINT+LDINTX, positive zero is OK.
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*/
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DUK_INTERNAL duk_bool_t duk_is_whole_get_int32_nonegzero(duk_double_t x, duk_int32_t *ival) {
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duk_int32_t t;
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t = duk_double_to_int32_t(x);
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if (!duk_double_equals((duk_double_t) t, x)) {
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return 0;
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}
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if (t == 0) {
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duk_double_union du;
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du.d = x;
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if (DUK_DBLUNION_HAS_SIGNBIT(&du)) {
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return 0;
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}
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}
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*ival = t;
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return 1;
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}
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/* Check whether a duk_double_t is a whole number in the 32-bit range, and if
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* so, return a duk_int32_t.
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*/
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DUK_INTERNAL duk_bool_t duk_is_whole_get_int32(duk_double_t x, duk_int32_t *ival) {
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duk_int32_t t;
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t = duk_double_to_int32_t(x);
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if (!duk_double_equals((duk_double_t) t, x)) {
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return 0;
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}
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*ival = t;
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return 1;
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}
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/* Division: division by zero is undefined behavior (and may in fact trap)
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* so it needs special handling for portability.
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*/
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DUK_INTERNAL DUK_INLINE duk_double_t duk_double_div(duk_double_t x, duk_double_t y) {
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#if !defined(DUK_USE_ALLOW_UNDEFINED_BEHAVIOR)
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if (DUK_UNLIKELY(duk_double_equals(y, 0.0) != 0)) {
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/* In C99+ division by zero is undefined behavior so
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* avoid it entirely. Hopefully the compiler is
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* smart enough to avoid emitting any actual code
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* because almost all practical platforms behave as
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* expected.
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*/
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if (x > 0.0) {
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if (DUK_SIGNBIT(y)) {
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return -DUK_DOUBLE_INFINITY;
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} else {
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return DUK_DOUBLE_INFINITY;
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}
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} else if (x < 0.0) {
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if (DUK_SIGNBIT(y)) {
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return DUK_DOUBLE_INFINITY;
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} else {
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return -DUK_DOUBLE_INFINITY;
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}
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} else {
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/* +/- 0, NaN */
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return DUK_DOUBLE_NAN;
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}
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}
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#endif
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return x / y;
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}
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/* Double and float byteorder changes. */
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DUK_INTERNAL DUK_INLINE void duk_dblunion_host_to_little(duk_double_union *u) {
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#if defined(DUK_USE_DOUBLE_LE)
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/* HGFEDCBA -> HGFEDCBA */
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DUK_UNREF(u);
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#elif defined(DUK_USE_DOUBLE_ME)
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duk_uint32_t a, b;
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/* DCBAHGFE -> HGFEDCBA */
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a = u->ui[0];
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b = u->ui[1];
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u->ui[0] = b;
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u->ui[1] = a;
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#elif defined(DUK_USE_DOUBLE_BE)
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/* ABCDEFGH -> HGFEDCBA */
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#if defined(DUK_USE_64BIT_OPS)
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u->ull[0] = DUK_BSWAP64(u->ull[0]);
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#else
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duk_uint32_t a, b;
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a = u->ui[0];
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b = u->ui[1];
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u->ui[0] = DUK_BSWAP32(b);
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u->ui[1] = DUK_BSWAP32(a);
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#endif
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#else
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#error internal error
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#endif
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}
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DUK_INTERNAL DUK_INLINE void duk_dblunion_little_to_host(duk_double_union *u) {
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duk_dblunion_host_to_little(u);
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}
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DUK_INTERNAL DUK_INLINE void duk_dblunion_host_to_big(duk_double_union *u) {
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#if defined(DUK_USE_DOUBLE_LE)
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/* HGFEDCBA -> ABCDEFGH */
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#if defined(DUK_USE_64BIT_OPS)
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u->ull[0] = DUK_BSWAP64(u->ull[0]);
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#else
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duk_uint32_t a, b;
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a = u->ui[0];
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b = u->ui[1];
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u->ui[0] = DUK_BSWAP32(b);
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u->ui[1] = DUK_BSWAP32(a);
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#endif
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#elif defined(DUK_USE_DOUBLE_ME)
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duk_uint32_t a, b;
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/* DCBAHGFE -> ABCDEFGH */
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a = u->ui[0];
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b = u->ui[1];
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u->ui[0] = DUK_BSWAP32(a);
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u->ui[1] = DUK_BSWAP32(b);
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#elif defined(DUK_USE_DOUBLE_BE)
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/* ABCDEFGH -> ABCDEFGH */
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DUK_UNREF(u);
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#else
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#error internal error
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#endif
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}
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DUK_INTERNAL DUK_INLINE void duk_dblunion_big_to_host(duk_double_union *u) {
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duk_dblunion_host_to_big(u);
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}
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DUK_INTERNAL DUK_INLINE void duk_fltunion_host_to_big(duk_float_union *u) {
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#if defined(DUK_USE_DOUBLE_LE) || defined(DUK_USE_DOUBLE_ME)
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/* DCBA -> ABCD */
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u->ui[0] = DUK_BSWAP32(u->ui[0]);
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#elif defined(DUK_USE_DOUBLE_BE)
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/* ABCD -> ABCD */
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DUK_UNREF(u);
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#else
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#error internal error
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#endif
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}
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DUK_INTERNAL DUK_INLINE void duk_fltunion_big_to_host(duk_float_union *u) {
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duk_fltunion_host_to_big(u);
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}
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/* Comparison: ensures comparison operates on exactly correct types, avoiding
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* some floating point comparison pitfalls (e.g. atan2() assertions failed on
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* -m32 with direct comparison, even with explicit casts).
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*/
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#if defined(DUK_USE_GCC_PRAGMAS)
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wfloat-equal"
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#elif defined(DUK_USE_CLANG_PRAGMAS)
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#pragma clang diagnostic push
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#pragma clang diagnostic ignored "-Wfloat-equal"
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#endif
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DUK_INTERNAL DUK_ALWAYS_INLINE duk_bool_t duk_double_equals(duk_double_t x, duk_double_t y) {
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return x == y;
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}
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DUK_INTERNAL DUK_ALWAYS_INLINE duk_bool_t duk_float_equals(duk_float_t x, duk_float_t y) {
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return x == y;
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}
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#if defined(DUK_USE_GCC_PRAGMAS)
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#pragma GCC diagnostic pop
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#elif defined(DUK_USE_CLANG_PRAGMAS)
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#pragma clang diagnostic pop
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#endif
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