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@mdboom
mdboom committed Dec 8, 2023
1 parent 05a370a commit 585f4f6
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Showing 11 changed files with 621 additions and 362 deletions.
25 changes: 9 additions & 16 deletions Include/cpython/longintrepr.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -61,6 +61,12 @@ typedef long stwodigits; /* signed variant of twodigits */
#define PyLong_BASE ((digit)1 << PyLong_SHIFT)
#define PyLong_MASK ((digit)(PyLong_BASE - 1))

#define PyLong_IS_LONG_MASK ((digit)1 << 31)
#define PyLong_IS_NEGATIVE_MASK ((digit)1 << 30)
#define PyLong_FLAGS_MASK (PyLong_IS_LONG_MASK | PyLong_IS_NEGATIVE_MASK)
#define PyLong_LONG_HEADER_DIGITS (2)

// MGDTODO: Update this docstring
/* Long integer representation.
The absolute value of a number is equal to
SUM(for i=0 through abs(ob_size)-1) ob_digit[i] * 2**(SHIFT*i)
Expand All @@ -79,14 +85,9 @@ typedef long stwodigits; /* signed variant of twodigits */
aware that ints abuse ob_size's sign bit.
*/

typedef struct _PyLongValue {
uintptr_t lv_tag; /* Number of digits, sign and flags */
digit ob_digit[1];
} _PyLongValue;

struct _longobject {
PyObject_HEAD
_PyLongValue long_value;
digit ob_digit[1];
};

PyAPI_FUNC(PyLongObject*) _PyLong_New(Py_ssize_t);
Expand All @@ -100,17 +101,10 @@ PyAPI_FUNC(PyLongObject*) _PyLong_FromDigits(
digit *digits);


/* Inline some internals for speed. These should be in pycore_long.h
* if user code didn't need them inlined. */

#define _PyLong_SIGN_MASK 3
#define _PyLong_NON_SIZE_BITS 3


static inline int
_PyLong_IsCompact(const PyLongObject* op) {
assert(PyType_HasFeature((op)->ob_base.ob_type, Py_TPFLAGS_LONG_SUBCLASS));
return op->long_value.lv_tag < (2 << _PyLong_NON_SIZE_BITS);
return !(op->ob_digit[0] & PyLong_IS_LONG_MASK);
}

#define PyUnstable_Long_IsCompact _PyLong_IsCompact
Expand All @@ -120,8 +114,7 @@ _PyLong_CompactValue(const PyLongObject *op)
{
assert(PyType_HasFeature((op)->ob_base.ob_type, Py_TPFLAGS_LONG_SUBCLASS));
assert(PyUnstable_Long_IsCompact(op));
Py_ssize_t sign = 1 - (op->long_value.lv_tag & _PyLong_SIGN_MASK);
return sign * (Py_ssize_t)op->long_value.ob_digit[0];
return ((op->ob_digit[0] & PyLong_IS_NEGATIVE_MASK) ? -1 : 1) * ((Py_ssize_t)op->ob_digit[0] & PyLong_MASK);
}

#define PyUnstable_Long_CompactValue _PyLong_CompactValue
Expand Down
163 changes: 116 additions & 47 deletions Include/internal/pycore_long.h
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,12 @@ extern "C" {
#include "pycore_global_objects.h"// _PY_NSMALLNEGINTS
#include "pycore_runtime.h" // _PyRuntime

// MGDTODO: Put this in the right place
#define PyLong_IS_LONG_MASK ((digit)1 << 31)
#define PyLong_IS_NEGATIVE_MASK ((digit)1 << 30)
#define PyLong_FLAGS_MASK (PyLong_IS_LONG_MASK | PyLong_IS_NEGATIVE_MASK)
#define PyLong_LONG_HEADER_DIGITS (2)

/*
* Default int base conversion size limitation: Denial of Service prevention.
*
Expand Down Expand Up @@ -168,14 +174,10 @@ PyAPI_FUNC(int) _PyLong_UnsignedLongLong_Converter(PyObject *, void *);
PyAPI_FUNC(int) _PyLong_Size_t_Converter(PyObject *, void *);

/* Long value tag bits:
* 0-1: Sign bits value = (1-sign), ie. negative=2, positive=0, zero=1.
* 2: Reserved for immortality bit
* 3+ Unsigned digit count
* 31: Is long? Is the representation that stores more than one digit?
* 30: Is negative
*/
#define SIGN_MASK 3
#define SIGN_ZERO 1
#define SIGN_NEGATIVE 2
#define NON_SIZE_BITS 3
// MGDTODO: Copy defines here?

/* The functions _PyLong_IsCompact and _PyLong_CompactValue are defined
* in Include/cpython/longobject.h, since they need to be inline.
Expand All @@ -185,132 +187,199 @@ PyAPI_FUNC(int) _PyLong_Size_t_Converter(PyObject *, void *);
* without risk of overflow.
*
* The inline functions need tag bits.
* For readability, rather than do `#define SIGN_MASK _PyLong_SIGN_MASK`
* For readability, rather than do `#define NON_SIZE_BITS _PyLong_NON_SIZE_BITS`
* we define them to the numbers in both places and then assert that
* they're the same.
*/
static_assert(SIGN_MASK == _PyLong_SIGN_MASK, "SIGN_MASK does not match _PyLong_SIGN_MASK");
static_assert(NON_SIZE_BITS == _PyLong_NON_SIZE_BITS, "NON_SIZE_BITS does not match _PyLong_NON_SIZE_BITS");
// MGDTODO: Restore the new equivalents here

/* All *compact" values are guaranteed to fit into
* a Py_ssize_t with at least one bit to spare.
* In other words, for 64 bit machines, compact
* will be signed 63 (or fewer) bit values
* a uint32_t with at least one bit to spare.
*/

/* Return 1 if the argument is compact int */
static inline int
_PyLong_IsNonNegativeCompact(const PyLongObject* op) {
assert(PyLong_Check(op));
return op->long_value.lv_tag <= (1 << NON_SIZE_BITS);
return (op->ob_digit[0] & PyLong_FLAGS_MASK) == (digit)0;
}


static inline int
_PyLong_BothAreCompact(const PyLongObject* a, const PyLongObject* b) {
assert(PyLong_Check(a));
assert(PyLong_Check(b));
return (a->long_value.lv_tag | b->long_value.lv_tag) < (2 << NON_SIZE_BITS);
return ((a->ob_digit[0] | b->ob_digit[0]) & PyLong_IS_LONG_MASK) == 0;
}

static inline bool
_PyLong_IsZero(const PyLongObject *op)
{
return (op->long_value.lv_tag & SIGN_MASK) == SIGN_ZERO;
return op->ob_digit[0] == 0;
}

static inline bool
_PyLong_IsNegative(const PyLongObject *op)
{
return (op->long_value.lv_tag & SIGN_MASK) == SIGN_NEGATIVE;
return op->ob_digit[0] & PyLong_IS_NEGATIVE_MASK;
}

static inline bool
_PyLong_IsPositive(const PyLongObject *op)
{
return (op->long_value.lv_tag & SIGN_MASK) == 0;
assert(PyLong_Check(op));

// MGDTODO: Optimize
return op->ob_digit[0] != 0 && ((op->ob_digit[0] & PyLong_IS_NEGATIVE_MASK) == 0);
}

static inline Py_ssize_t
_PyLong_DigitCount(const PyLongObject *op)
{
assert(PyLong_Check(op));
return op->long_value.lv_tag >> NON_SIZE_BITS;
// assert(PyLong_Check(op));
if (_PyLong_IsCompact(op)) {
return _PyLong_IsZero(op) ? 0 : 1;
} else {
return (Py_ssize_t)op->ob_digit[1] | (Py_ssize_t)(op->ob_digit[0] & PyLong_MASK) << 32;
}
}

/* Equivalent to _PyLong_DigitCount(op) * _PyLong_NonCompactSign(op) */
static inline Py_ssize_t
_PyLong_SignedDigitCount(const PyLongObject *op)
static inline int
_PyLong_NonCompactSign(const PyLongObject *op)
{
assert(PyLong_Check(op));
Py_ssize_t sign = 1 - (op->long_value.lv_tag & SIGN_MASK);
return sign * (Py_ssize_t)(op->long_value.lv_tag >> NON_SIZE_BITS);
assert(!_PyLong_IsCompact(op));
return (op->ob_digit[0] & PyLong_IS_NEGATIVE_MASK) ? -1 : 1;
}

static inline int
_PyLong_CompactSign(const PyLongObject *op)
{
assert(PyLong_Check(op));
assert(_PyLong_IsCompact(op));
return 1 - (op->long_value.lv_tag & SIGN_MASK);
if (op->ob_digit[0] == 0) {
return 0;
}
return (op->ob_digit[0] & PyLong_IS_NEGATIVE_MASK) ? -1 : 1;
}

static inline int
_PyLong_NonCompactSign(const PyLongObject *op)
/* Equivalent to _PyLong_DigitCount(op) * _PyLong_NonCompactSign(op) */
static inline Py_ssize_t
_PyLong_SignedDigitCount(const PyLongObject *op)
{
assert(PyLong_Check(op));
assert(!_PyLong_IsCompact(op));
return 1 - (op->long_value.lv_tag & SIGN_MASK);
if (op->ob_digit[0] == 0) {
return 0;
} else if (_PyLong_IsCompact(op)) {
return (op->ob_digit[0] & PyLong_IS_NEGATIVE_MASK) ? -1 : 1;
} else {
return (Py_ssize_t)_PyLong_DigitCount(op) * _PyLong_NonCompactSign(op);
}
}

/* Do a and b have the same sign? */
static inline int
_PyLong_SameSign(const PyLongObject *a, const PyLongObject *b)
{
return (a->long_value.lv_tag & SIGN_MASK) == (b->long_value.lv_tag & SIGN_MASK);
if (a->ob_digit[0] == 0 && b->ob_digit[0] == 0) {
return 1;
}
return !((a->ob_digit[0] ^ b->ob_digit[0]) & PyLong_IS_NEGATIVE_MASK);
}

#define TAG_FROM_SIGN_AND_SIZE(sign, size) ((1 - (sign)) | ((size) << NON_SIZE_BITS))
static inline void
_PyLong_SetSign(PyLongObject *op, int sign)
{
assert(-1 <= sign && sign <= 1);
switch (sign) {
case 0:
op->ob_digit[0] = 0;
break;
case 1:
op->ob_digit[0] |= ~PyLong_IS_NEGATIVE_MASK;
break;
case -1:
op->ob_digit[0] |= PyLong_IS_NEGATIVE_MASK;
break;
}
}

static inline void
_PyLong_SetSignAndDigitCount(PyLongObject *op, int sign, Py_ssize_t size)
{
assert(size >= 0);
assert(-1 <= sign && sign <= 1);
assert(sign != 0 || size == 0);
op->long_value.lv_tag = TAG_FROM_SIGN_AND_SIZE(sign, (size_t)size);
if (size == 0) {
assert(sign == 0);
op->ob_digit[0] = 0;
} else if (size == 1) {
// assert(op->ob_digit[0] != 0);
// MGDTODO: Optimize
if (_PyLong_IsCompact(op)) {
op->ob_digit[0] = (
((sign == -1) ? PyLong_IS_NEGATIVE_MASK : 0) |
(op->ob_digit[0] & PyLong_MASK)
);
} else {
op->ob_digit[0] = (
((sign == -1) ? PyLong_IS_NEGATIVE_MASK : 0) |
(op->ob_digit[PyLong_LONG_HEADER_DIGITS] & PyLong_MASK)
);
}
} else {
// assert(op->ob_digit[0] & PyLong_IS_LONG_MASK);
// assert(_PyLong_DigitCount(op) >= size);
op->ob_digit[0] = (
PyLong_IS_LONG_MASK |
((sign == -1) ? PyLong_IS_NEGATIVE_MASK : 0) |
(size >> 32)
);
op->ob_digit[1] = (size & 0xffffffff);
}
}

static inline void
_PyLong_SetDigitCount(PyLongObject *op, Py_ssize_t size)
{
assert(size >= 0);
op->long_value.lv_tag = (((size_t)size) << NON_SIZE_BITS) | (op->long_value.lv_tag & SIGN_MASK);
assert(!_PyLong_IsCompact(op));
if (size == 0) {
op->ob_digit[0] = 0;
} else if (size == 1) {
if (!_PyLong_IsCompact(op)) {
op->ob_digit[0] = (
(op->ob_digit[0] & PyLong_IS_NEGATIVE_MASK) |
(op->ob_digit[PyLong_LONG_HEADER_DIGITS] & PyLong_MASK)
);
}
} else {
assert(op->ob_digit[0] & PyLong_IS_LONG_MASK);
assert(_PyLong_DigitCount(op) >= size);
op->ob_digit[0] = (
(op->ob_digit[0] & PyLong_FLAGS_MASK) |
size >> 32
);
op->ob_digit[1] = (size & 0xffffffff);
}
}

#define NON_SIZE_MASK ~((1 << NON_SIZE_BITS) - 1)

static inline void
_PyLong_FlipSign(PyLongObject *op) {
unsigned int flipped_sign = 2 - (op->long_value.lv_tag & SIGN_MASK);
op->long_value.lv_tag &= NON_SIZE_MASK;
op->long_value.lv_tag |= flipped_sign;
op->ob_digit[0] ^= PyLong_IS_NEGATIVE_MASK;
}

// MGDTODO: These objects will be 4 bytes larger than needed.

#define _PyLong_DIGIT_INIT(val) \
{ \
.ob_base = _PyObject_HEAD_INIT(&PyLong_Type), \
.long_value = { \
.lv_tag = TAG_FROM_SIGN_AND_SIZE( \
(val) == 0 ? 0 : ((val) < 0 ? -1 : 1), \
(val) == 0 ? 0 : 1), \
{ ((val) >= 0 ? (val) : -(val)) }, \
.ob_digit = { \
(((val) < 0) ? PyLong_IS_NEGATIVE_MASK : 0) | \
(((val) < 0) ? -(val) : (val)) \
} \
}

#define _PyLong_FALSE_TAG TAG_FROM_SIGN_AND_SIZE(0, 0)
#define _PyLong_TRUE_TAG TAG_FROM_SIGN_AND_SIZE(1, 1)

#ifdef __cplusplus
}
#endif
Expand Down
6 changes: 3 additions & 3 deletions Modules/_decimal/_decimal.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2299,17 +2299,17 @@ dec_from_long(PyTypeObject *type, PyObject *v,
uint8_t sign = _PyLong_IsNegative(l) ? MPD_NEG : MPD_POS;

if (_PyLong_IsCompact(l)) {
_dec_settriple(dec, sign, l->long_value.ob_digit[0], 0);
_dec_settriple(dec, sign, l->ob_digit[0] & PyLong_MASK, 0);
mpd_qfinalize(MPD(dec), ctx, status);
return dec;
}
size_t len = _PyLong_DigitCount(l);

#if PYLONG_BITS_IN_DIGIT == 30
mpd_qimport_u32(MPD(dec), l->long_value.ob_digit, len, sign, PyLong_BASE,
mpd_qimport_u32(MPD(dec), l->ob_digit + 2, len, sign, PyLong_BASE,
ctx, status);
#elif PYLONG_BITS_IN_DIGIT == 15
mpd_qimport_u16(MPD(dec), l->long_value.ob_digit, len, sign, PyLong_BASE,
mpd_qimport_u16(MPD(dec), l->ob_digit + 2, len, sign, PyLong_BASE,
ctx, status);
#else
#error "PYLONG_BITS_IN_DIGIT should be 15 or 30"
Expand Down
10 changes: 3 additions & 7 deletions Objects/boolobject.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -171,7 +171,7 @@ bool_dealloc(PyObject *boolean)
PyTypeObject PyBool_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"bool",
offsetof(struct _longobject, long_value.ob_digit), /* tp_basicsize */
offsetof(struct _longobject, ob_digit) + sizeof(digit), /* tp_basicsize */ // MGDTODO: Too big?
sizeof(digit), /* tp_itemsize */
bool_dealloc, /* tp_dealloc */
0, /* tp_vectorcall_offset */
Expand Down Expand Up @@ -214,14 +214,10 @@ PyTypeObject PyBool_Type = {

struct _longobject _Py_FalseStruct = {
PyObject_HEAD_INIT(&PyBool_Type)
{ .lv_tag = _PyLong_FALSE_TAG,
{ 0 }
}
.ob_digit = { 0 },
};

struct _longobject _Py_TrueStruct = {
PyObject_HEAD_INIT(&PyBool_Type)
{ .lv_tag = _PyLong_TRUE_TAG,
{ 1 }
}
.ob_digit = { 1 },
};
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