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bpo-45412: Move _Py_SET_53BIT_PRECISION_START to pycore_pymath.h (GH-28882)
Move the following macros , to pycore_pymath.h (internal C API): * _Py_SET_53BIT_PRECISION_HEADER * _Py_SET_53BIT_PRECISION_START * _Py_SET_53BIT_PRECISION_END PEP 7: add braces to if and "do { ... } while (0)" in these macros. Move also _Py_get_387controlword() and _Py_set_387controlword() definitions to pycore_pymath.h. These functions are no longer exported. pystrtod.c now includes pycore_pymath.h.
1 parent a9fe1a8 commit 7103356

5 files changed

Lines changed: 113 additions & 90 deletions

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‎Include/internal/pycore_pymath.h‎

Lines changed: 91 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -74,6 +74,97 @@ static inline void _Py_ADJUST_ERANGE2(double x, double y)
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#define _Py_InIntegralTypeRange(type, v) \
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(_Py_IntegralTypeMin(type) <= v && v <= _Py_IntegralTypeMax(type))
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//--- Implementation of the HAVE_PY_SET_53BIT_PRECISION macro -------------
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//--- defined in pyport.h -------------------------------------------------
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//
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// Give appropriate definitions for the following three macros:
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//
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// _Py_SET_53BIT_PRECISION_HEADER : any variable declarations needed to
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// use the two macros below.
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// _Py_SET_53BIT_PRECISION_START : store original FPU settings, and
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// set FPU to 53-bit precision/round-half-to-even
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// _Py_SET_53BIT_PRECISION_END : restore original FPU settings
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// Get and set x87 control word for gcc/x86
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#ifdef HAVE_GCC_ASM_FOR_X87
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// Functions defined in Python/pymath.c
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extern unsigned short _Py_get_387controlword(void);
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extern void _Py_set_387controlword(unsigned short);
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#define _Py_SET_53BIT_PRECISION_HEADER \
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unsigned short old_387controlword, new_387controlword
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#define _Py_SET_53BIT_PRECISION_START \
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do { \
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old_387controlword = _Py_get_387controlword(); \
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new_387controlword = (old_387controlword & ~0x0f00) | 0x0200; \
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if (new_387controlword != old_387controlword) { \
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_Py_set_387controlword(new_387controlword); \
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} \
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} while (0)
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#define _Py_SET_53BIT_PRECISION_END \
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do { \
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if (new_387controlword != old_387controlword) { \
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_Py_set_387controlword(old_387controlword); \
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} \
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} while (0)
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#endif
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// Get and set x87 control word for VisualStudio/x86.
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// x87 is not supported in 64-bit or ARM.
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#if defined(_MSC_VER) && !defined(_WIN64) && !defined(_M_ARM)
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#define _Py_SET_53BIT_PRECISION_HEADER \
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unsigned int old_387controlword, new_387controlword, out_387controlword
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// We use the __control87_2 function to set only the x87 control word.
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// The SSE control word is unaffected.
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#define _Py_SET_53BIT_PRECISION_START \
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do { \
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__control87_2(0, 0, &old_387controlword, NULL); \
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new_387controlword = \
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(old_387controlword & ~(_MCW_PC | _MCW_RC)) | (_PC_53 | _RC_NEAR); \
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if (new_387controlword != old_387controlword) { \
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__control87_2(new_387controlword, _MCW_PC | _MCW_RC, \
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&out_387controlword, NULL); \
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} \
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} while (0)
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#define _Py_SET_53BIT_PRECISION_END \
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do { \
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if (new_387controlword != old_387controlword) { \
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__control87_2(old_387controlword, _MCW_PC | _MCW_RC, \
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&out_387controlword, NULL); \
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} \
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} while (0)
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#endif
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#ifdef HAVE_GCC_ASM_FOR_MC68881
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#define _Py_SET_53BIT_PRECISION_HEADER \
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unsigned int old_fpcr, new_fpcr
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#define _Py_SET_53BIT_PRECISION_START \
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do { \
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__asm__ ("fmove.l %%fpcr,%0" : "=g" (old_fpcr)); \
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/* Set double precision / round to nearest. */ \
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new_fpcr = (old_fpcr & ~0xf0) | 0x80; \
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if (new_fpcr != old_fpcr) { \
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__asm__ volatile ("fmove.l %0,%%fpcr" : : "g" (new_fpcr));\
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} \
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} while (0)
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#define _Py_SET_53BIT_PRECISION_END \
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do { \
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if (new_fpcr != old_fpcr) { \
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__asm__ volatile ("fmove.l %0,%%fpcr" : : "g" (old_fpcr)); \
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} \
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} while (0)
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#endif
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// Default definitions are empty
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#ifndef _Py_SET_53BIT_PRECISION_HEADER
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# define _Py_SET_53BIT_PRECISION_HEADER
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# define _Py_SET_53BIT_PRECISION_START
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# define _Py_SET_53BIT_PRECISION_END
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#endif
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#ifdef __cplusplus
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}
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#endif

‎Include/pymath.h‎

Lines changed: 5 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -78,13 +78,6 @@ PyAPI_FUNC(double) _Py_force_double(double);
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#endif
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#endif
8080

81-
#ifndef Py_LIMITED_API
82-
#ifdef HAVE_GCC_ASM_FOR_X87
83-
PyAPI_FUNC(unsigned short) _Py_get_387controlword(void);
84-
PyAPI_FUNC(void) _Py_set_387controlword(unsigned short);
85-
#endif
86-
#endif
87-
8881
/* Py_IS_NAN(X)
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* Return 1 if float or double arg is a NaN, else 0.
9083
* Caution:
@@ -95,11 +88,11 @@ PyAPI_FUNC(void) _Py_set_387controlword(unsigned short);
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* Note: PC/pyconfig.h defines Py_IS_NAN as _isnan
9689
*/
9790
#ifndef Py_IS_NAN
98-
#if defined HAVE_DECL_ISNAN && HAVE_DECL_ISNAN == 1
99-
#define Py_IS_NAN(X) isnan(X)
100-
#else
101-
#define Py_IS_NAN(X) ((X) != (X))
102-
#endif
91+
# if defined HAVE_DECL_ISNAN && HAVE_DECL_ISNAN == 1
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# define Py_IS_NAN(X) isnan(X)
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# else
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# define Py_IS_NAN(X) ((X) != (X))
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# endif
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#endif
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/* Py_IS_INFINITY(X)

‎Include/pyport.h‎

Lines changed: 12 additions & 73 deletions
Original file line numberDiff line numberDiff line change
@@ -335,86 +335,25 @@ extern "C" {
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*
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* #define HAVE_PY_SET_53BIT_PRECISION 1
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*
338-
* and also give appropriate definitions for the following three macros:
339-
*
340-
* _PY_SET_53BIT_PRECISION_START : store original FPU settings, and
341-
* set FPU to 53-bit precision/round-half-to-even
342-
* _PY_SET_53BIT_PRECISION_END : restore original FPU settings
343-
* _PY_SET_53BIT_PRECISION_HEADER : any variable declarations needed to
344-
* use the two macros above.
345-
*
346338
* The macros are designed to be used within a single C function: see
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* Python/pystrtod.c for an example of their use.
348340
*/
349341

350-
/* get and set x87 control word for gcc/x86 */
342+
// HAVE_PY_SET_53BIT_PRECISION macro must be kept in sync with pycore_pymath.h
351343
#ifdef HAVE_GCC_ASM_FOR_X87
352-
#define HAVE_PY_SET_53BIT_PRECISION 1
353-
/* _Py_get/set_387controlword functions are defined in Python/pymath.c */
354-
#define _Py_SET_53BIT_PRECISION_HEADER \
355-
unsigned short old_387controlword, new_387controlword
356-
#define _Py_SET_53BIT_PRECISION_START \
357-
do { \
358-
old_387controlword = _Py_get_387controlword(); \
359-
new_387controlword = (old_387controlword & ~0x0f00) | 0x0200; \
360-
if (new_387controlword != old_387controlword) \
361-
_Py_set_387controlword(new_387controlword); \
362-
} while (0)
363-
#define _Py_SET_53BIT_PRECISION_END \
364-
if (new_387controlword != old_387controlword) \
365-
_Py_set_387controlword(old_387controlword)
366-
#endif
367-
368-
/* get and set x87 control word for VisualStudio/x86 */
369-
#if defined(_MSC_VER) && !defined(_WIN64) && !defined(_M_ARM) /* x87 not supported in 64-bit or ARM */
370-
#define HAVE_PY_SET_53BIT_PRECISION 1
371-
#define _Py_SET_53BIT_PRECISION_HEADER \
372-
unsigned int old_387controlword, new_387controlword, out_387controlword
373-
/* We use the __control87_2 function to set only the x87 control word.
374-
The SSE control word is unaffected. */
375-
#define _Py_SET_53BIT_PRECISION_START \
376-
do { \
377-
__control87_2(0, 0, &old_387controlword, NULL); \
378-
new_387controlword = \
379-
(old_387controlword & ~(_MCW_PC | _MCW_RC)) | (_PC_53 | _RC_NEAR); \
380-
if (new_387controlword != old_387controlword) \
381-
__control87_2(new_387controlword, _MCW_PC | _MCW_RC, \
382-
&out_387controlword, NULL); \
383-
} while (0)
384-
#define _Py_SET_53BIT_PRECISION_END \
385-
do { \
386-
if (new_387controlword != old_387controlword) \
387-
__control87_2(old_387controlword, _MCW_PC | _MCW_RC, \
388-
&out_387controlword, NULL); \
389-
} while (0)
344+
// Get and set x87 control word for gcc/x86
345+
# define HAVE_PY_SET_53BIT_PRECISION 1
346+
#endif
347+
#if defined(_MSC_VER) && !defined(_WIN64) && !defined(_M_ARM)
348+
// Get and set x87 control word for VisualStudio/x86.
349+
// x87 not supported in 64-bit or ARM.
350+
# define HAVE_PY_SET_53BIT_PRECISION 1
390351
#endif
391-
392352
#ifdef HAVE_GCC_ASM_FOR_MC68881
393-
#define HAVE_PY_SET_53BIT_PRECISION 1
394-
#define _Py_SET_53BIT_PRECISION_HEADER \
395-
unsigned int old_fpcr, new_fpcr
396-
#define _Py_SET_53BIT_PRECISION_START \
397-
do { \
398-
__asm__ ("fmove.l %%fpcr,%0" : "=g" (old_fpcr)); \
399-
/* Set double precision / round to nearest. */ \
400-
new_fpcr = (old_fpcr & ~0xf0) | 0x80; \
401-
if (new_fpcr != old_fpcr) \
402-
__asm__ volatile ("fmove.l %0,%%fpcr" : : "g" (new_fpcr)); \
403-
} while (0)
404-
#define _Py_SET_53BIT_PRECISION_END \
405-
do { \
406-
if (new_fpcr != old_fpcr) \
407-
__asm__ volatile ("fmove.l %0,%%fpcr" : : "g" (old_fpcr)); \
408-
} while (0)
409-
#endif
410-
411-
/* default definitions are empty */
412-
#ifndef HAVE_PY_SET_53BIT_PRECISION
413-
#define _Py_SET_53BIT_PRECISION_HEADER
414-
#define _Py_SET_53BIT_PRECISION_START
415-
#define _Py_SET_53BIT_PRECISION_END
353+
# define HAVE_PY_SET_53BIT_PRECISION 1
416354
#endif
417355

356+
418357
/* If we can't guarantee 53-bit precision, don't use the code
419358
in Python/dtoa.c, but fall back to standard code. This
420359
means that repr of a float will be long (17 sig digits).
@@ -430,14 +369,14 @@ extern "C" {
430369
#if !defined(DOUBLE_IS_LITTLE_ENDIAN_IEEE754) && \
431370
!defined(DOUBLE_IS_BIG_ENDIAN_IEEE754) && \
432371
!defined(DOUBLE_IS_ARM_MIXED_ENDIAN_IEEE754)
433-
#define PY_NO_SHORT_FLOAT_REPR
372+
# define PY_NO_SHORT_FLOAT_REPR
434373
#endif
435374

436375
/* double rounding is symptomatic of use of extended precision on x86. If
437376
we're seeing double rounding, and we don't have any mechanism available for
438377
changing the FPU rounding precision, then don't use Python/dtoa.c. */
439378
#if defined(X87_DOUBLE_ROUNDING) && !defined(HAVE_PY_SET_53BIT_PRECISION)
440-
#define PY_NO_SHORT_FLOAT_REPR
379+
# define PY_NO_SHORT_FLOAT_REPR
441380
#endif
442381

443382

‎Python/pymath.c‎

Lines changed: 4 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -13,10 +13,10 @@ double _Py_force_double(double x)
1313
}
1414
#endif
1515

16-
#ifdef HAVE_GCC_ASM_FOR_X87
1716

18-
/* inline assembly for getting and setting the 387 FPU control word on
19-
gcc/x86 */
17+
#ifdef HAVE_GCC_ASM_FOR_X87
18+
// Inline assembly for getting and setting the 387 FPU control word on
19+
// GCC/x86.
2020
#ifdef _Py_MEMORY_SANITIZER
2121
__attribute__((no_sanitize_memory))
2222
#endif
@@ -29,8 +29,7 @@ unsigned short _Py_get_387controlword(void) {
2929
void _Py_set_387controlword(unsigned short cw) {
3030
__asm__ __volatile__ ("fldcw %0" : : "m" (cw));
3131
}
32-
33-
#endif
32+
#endif // HAVE_GCC_ASM_FOR_X87
3433

3534

3635
#ifndef HAVE_HYPOT

‎Python/pystrtod.c‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2,6 +2,7 @@
22

33
#include <Python.h>
44
#include "pycore_dtoa.h"
5+
#include "pycore_pymath.h" // _Py_SET_53BIT_PRECISION_START
56
#include <locale.h>
67

78
/* Case-insensitive string match used for nan and inf detection; t should be

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