Cray J90 fixes for long ints.
This was a convenient excuse to create the pyport.h file recently
discussed!
Please use new Py_ARITHMETIC_RIGHT_SHIFT when right-shifting a
signed int and you *need* sign-extension. This is #define'd in
pyport.h, keying off new config symbol SIGNED_RIGHT_SHIFT_ZERO_FILLS.
If you're running on a platform that needs that symbol #define'd,
the std tests never would have worked for you (in particular,
at least test_long would have failed).
The autoconfig stuff got added to Python after my Unix days, so
I don't know how that works. Would someone please look into doing
& testing an auto-config of the SIGNED_RIGHT_SHIFT_ZERO_FILLS
symbol? It needs to be defined if & only if, e.g., (-1) >> 3 is
not -1.
diff --git a/Include/Python.h b/Include/Python.h
index 3389c0a..b36b5da 100644
--- a/Include/Python.h
+++ b/Include/Python.h
@@ -31,6 +31,7 @@
#include "patchlevel.h"
#include "config.h"
+#include "pyport.h"
/* config.h may or may not define DL_IMPORT */
#ifndef DL_IMPORT /* declarations for DLL import/export */
diff --git a/Include/longintrepr.h b/Include/longintrepr.h
index 4ddbd06..fed01ed 100644
--- a/Include/longintrepr.h
+++ b/Include/longintrepr.h
@@ -18,7 +18,7 @@
/* Parameters of the long integer representation.
These shouldn't have to be changed as C should guarantee that a short
- contains at least 16 bits, but it's made changeable any way.
+ contains at least 16 bits, but it's made changeable anyway.
Note: 'digit' should be able to hold 2*MASK+1, and 'twodigits'
should be able to hold the intermediate results in 'mul'
(at most MASK << SHIFT).
@@ -28,8 +28,9 @@
typedef unsigned short digit;
typedef unsigned int wdigit; /* digit widened to parameter size */
-typedef unsigned long twodigits;
-typedef long stwodigits; /* signed variant of twodigits */
+#define BASE_TWODIGITS_TYPE long
+typedef unsigned BASE_TWODIGITS_TYPE twodigits;
+typedef BASE_TWODIGITS_TYPE stwodigits; /* signed variant of twodigits */
#define SHIFT 15
#define BASE ((digit)1 << SHIFT)
diff --git a/Include/pyport.h b/Include/pyport.h
new file mode 100644
index 0000000..558b17d
--- /dev/null
+++ b/Include/pyport.h
@@ -0,0 +1,57 @@
+/***********************************************************
+Copyright (c) 2000, BeOpen.com.
+All rights reserved.
+
+See the file "Misc/COPYRIGHT" for information on usage and
+redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+******************************************************************/
+
+#ifndef Py_PYPORT_H
+#define Py_PYPORT_H 1
+
+/**************************************************************************
+Symbols and macros to supply platform-independent interfaces to basic
+C-language operations whose spellings vary across platforms.
+
+Please try to make documentation here as clear as possible: by definition,
+the stuff here is trying to illuminate C's darkest corners.
+
+Config #defines referenced here:
+
+SIGNED_RIGHT_SHIFT_ZERO_FILLS
+Meaning: To be defined iff i>>j does not extend the sign bit when i is a
+ signed integral type and i < 0.
+Used in: Py_ARITHMETIC_RIGHT_SHIFT
+**************************************************************************/
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Py_ARITHMETIC_RIGHT_SHIFT
+ * C doesn't define whether a right-shift of a signed integer sign-extends
+ * or zero-fills. Here a macro to force sign extension:
+ * Py_ARITHMETIC_RIGHT_SHIFT(TYPE, I, J)
+ * Return I >> J, forcing sign extension.
+ * Requirements:
+ * I is of basic signed type TYPE (char, short, int, long, or long long).
+ * TYPE is one of char, short, int, long, or long long, although long long
+ * must not be used except on platforms that support it.
+ * J is an integer >= 0 and strictly less than the number of bits in TYPE
+ * (because C doesn't define what happens for J outside that range either).
+ * Caution:
+ * I may be evaluated more than once.
+ */
+#ifdef SIGNED_RIGHT_SHIFT_ZERO_FILLS
+#define Py_ARITHMETIC_RIGHT_SHIFT(TYPE, I, J) \
+ ((I) < 0 ? ~((~(unsigned TYPE)(I)) >> (J)) : (I) >> (J))
+#else
+#define Py_ARITHMETIC_RIGHT_SHIFT(TYPE, I, J) ((I) >> (J))
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* Py_PYPORT_H */
diff --git a/Objects/intobject.c b/Objects/intobject.c
index ba3dde1..a5dc134 100644
--- a/Objects/intobject.c
+++ b/Objects/intobject.c
@@ -721,10 +721,7 @@
a = 0;
}
else {
- if (a < 0)
- a = ~( ~(unsigned long)a >> b );
- else
- a = (unsigned long)a >> b;
+ a = Py_ARITHMETIC_RIGHT_SHIFT(long, a, b);
}
return PyInt_FromLong(a);
}
diff --git a/Objects/longobject.c b/Objects/longobject.c
index a28dbaf..df3c6a5 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -571,7 +571,8 @@
int last = abs(a->ob_size);
int basebits = 1;
i = base;
- while ((i >>= 1) > 1) ++basebits;
+ while ((i >>= 1) > 1)
+ ++basebits;
i = 0;
for (;;) {
@@ -853,7 +854,9 @@
carry += v->ob_digit[i+k] - z
+ ((twodigits)zz << SHIFT);
v->ob_digit[i+k] = carry & MASK;
- carry = (carry >> SHIFT) - zz;
+ carry = Py_ARITHMETIC_RIGHT_SHIFT(BASE_TWODIGITS_TYPE,
+ carry, SHIFT);
+ carry -= zz;
}
if (i+k < size_v) {
@@ -870,7 +873,9 @@
for (i = 0; i < size_w && i+k < size_v; ++i) {
carry += v->ob_digit[i+k] + w->ob_digit[i];
v->ob_digit[i+k] = carry & MASK;
- carry >>= SHIFT;
+ carry = Py_ARITHMETIC_RIGHT_SHIFT(
+ BASE_TWODIGITS_TYPE,
+ carry, SHIFT);
}
}
} /* for j, k */
@@ -988,8 +993,6 @@
for (i = 0; i < size_b; ++i) {
carry += a->ob_digit[i] + b->ob_digit[i];
z->ob_digit[i] = carry & MASK;
- /* The following assumes unsigned shifts don't
- propagate the sign bit. */
carry >>= SHIFT;
}
for (; i < size_a; ++i) {
diff --git a/acconfig.h b/acconfig.h
index ab775e9..210f381 100644
--- a/acconfig.h
+++ b/acconfig.h
@@ -169,5 +169,10 @@
/* Defined when any dynamic module loading is enabled */
#undef HAVE_DYNAMIC_LOADING
+/* Define if i>>j for signed int i does not extend the sign bit
+ when i < 0
+*/
+#undef SIGNED_RIGHT_SHIFT_ZERO_FILLS
+
/* Leave that blank line there-- autoheader needs it! */