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Unified Diff: Modules/_decimal/libmpdec/bits.h

Issue 7652: Merge C version of decimal into py3k.
Patch Set: Created 7 years, 5 months ago
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/Modules/_decimal/libmpdec/bits.h Sat Mar 10 18:12:20 2012 +0100
@@ -0,0 +1,192 @@
+/*
+ * Copyright (c) 2008-2010 Stefan Krah. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+
+#ifndef BITS_H
+#define BITS_H
+
+
+#include "mpdecimal.h"
+#include <stdio.h>
+
+
+/* Check if n is a power of 2. */
+static inline int
+ispower2(mpd_size_t n)
+{
+ return n != 0 && (n & (n-1)) == 0;
+}
+
+#if defined(ANSI)
+/*
+ * Return the most significant bit position of n from 0 to 31 (63).
+ * Assumptions: n != 0.
+ */
+static inline int
+mpd_bsr(mpd_size_t n)
+{
+ int pos = 0;
+ mpd_size_t tmp;
+
+#ifdef CONFIG_64
+ tmp = n >> 32;
+ if (tmp != 0) { n = tmp; pos += 32; }
+#endif
+ tmp = n >> 16;
+ if (tmp != 0) { n = tmp; pos += 16; }
+ tmp = n >> 8;
+ if (tmp != 0) { n = tmp; pos += 8; }
+ tmp = n >> 4;
+ if (tmp != 0) { n = tmp; pos += 4; }
+ tmp = n >> 2;
+ if (tmp != 0) { n = tmp; pos += 2; }
+ tmp = n >> 1;
+ if (tmp != 0) { n = tmp; pos += 1; }
+
+ return pos + (int)n - 1;
+}
+
+/*
+ * Return the least significant bit position of n from 0 to 31 (63).
+ * Assumptions: n != 0.
+ */
+static inline int
+mpd_bsf(mpd_size_t n)
+{
+ int pos;
+
+#ifdef CONFIG_64
+ pos = 63;
+ if (n & 0x00000000FFFFFFFFULL) { pos -= 32; } else { n >>= 32; }
+ if (n & 0x000000000000FFFFULL) { pos -= 16; } else { n >>= 16; }
+ if (n & 0x00000000000000FFULL) { pos -= 8; } else { n >>= 8; }
+ if (n & 0x000000000000000FULL) { pos -= 4; } else { n >>= 4; }
+ if (n & 0x0000000000000003ULL) { pos -= 2; } else { n >>= 2; }
+ if (n & 0x0000000000000001ULL) { pos -= 1; }
+#else
+ pos = 31;
+ if (n & 0x000000000000FFFFUL) { pos -= 16; } else { n >>= 16; }
+ if (n & 0x00000000000000FFUL) { pos -= 8; } else { n >>= 8; }
+ if (n & 0x000000000000000FUL) { pos -= 4; } else { n >>= 4; }
+ if (n & 0x0000000000000003UL) { pos -= 2; } else { n >>= 2; }
+ if (n & 0x0000000000000001UL) { pos -= 1; }
+#endif
+ return pos;
+}
+/* END ANSI */
+
+#elif defined(ASM)
+/*
+ * Bit scan reverse. Assumptions: a != 0.
+ */
+static inline int
+mpd_bsr(mpd_size_t a)
+{
+ mpd_size_t retval;
+
+ __asm__ (
+#ifdef CONFIG_64
+ "bsrq %1, %0\n\t"
+#else
+ "bsr %1, %0\n\t"
+#endif
+ :"=r" (retval)
+ :"r" (a)
+ :"cc"
+ );
+
+ return (int)retval;
+}
+
+/*
+ * Bit scan forward. Assumptions: a != 0.
+ */
+static inline int
+mpd_bsf(mpd_size_t a)
+{
+ mpd_size_t retval;
+
+ __asm__ (
+#ifdef CONFIG_64
+ "bsfq %1, %0\n\t"
+#else
+ "bsf %1, %0\n\t"
+#endif
+ :"=r" (retval)
+ :"r" (a)
+ :"cc"
+ );
+
+ return (int)retval;
+}
+/* END ASM */
+
+#elif defined(MASM)
+#include <intrin.h>
+/*
+ * Bit scan reverse. Assumptions: a != 0.
+ */
+static inline int __cdecl
+mpd_bsr(mpd_size_t a)
+{
+ unsigned long retval;
+
+#ifdef CONFIG_64
+ _BitScanReverse64(&retval, a);
+#else
+ _BitScanReverse(&retval, a);
+#endif
+
+ return (int)retval;
+}
+
+/*
+ * Bit scan forward. Assumptions: a != 0.
+ */
+static inline int __cdecl
+mpd_bsf(mpd_size_t a)
+{
+ unsigned long retval;
+
+#ifdef CONFIG_64
+ _BitScanForward64(&retval, a);
+#else
+ _BitScanForward(&retval, a);
+#endif
+
+ return (int)retval;
+}
+/* END MASM (_MSC_VER) */
+#else
+ #error "missing preprocessor definitions"
+#endif /* BSR/BSF */
+
+
+#endif /* BITS_H */
+
+
+
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