diff libgcc/config/libbid/bid_from_int.c @ 0:a06113de4d67

first commit
author kent <kent@cr.ie.u-ryukyu.ac.jp>
date Fri, 17 Jul 2009 14:47:48 +0900
parents
children 04ced10e8804
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libgcc/config/libbid/bid_from_int.c	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,349 @@
+/* Copyright (C) 2007, 2009  Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+#include "bid_internal.h"
+
+/*****************************************************************************
+ *  BID64_round_integral_exact
+ ****************************************************************************/
+
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid64_from_int32 (UINT64 * pres,
+		  int *px _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
+  int x = *px;
+#else
+UINT64
+bid64_from_int32 (int x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
+#endif
+  UINT64 res;
+
+  // if integer is negative, put the absolute value
+  // in the lowest 32bits of the result
+  if ((x & SIGNMASK32) == SIGNMASK32) {
+    // negative int32
+    x = ~x + 1;	// 2's complement of x
+    res = (unsigned int) x | 0xb1c0000000000000ull;
+    // (exp << 53)) = biased exp. is 0
+  } else {	// positive int32
+    res = x | 0x31c0000000000000ull;	// (exp << 53)) = biased exp. is 0
+  }
+  BID_RETURN (res);
+}
+
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid64_from_uint32 (UINT64 * pres, unsigned int *px
+		   _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
+  unsigned int x = *px;
+#else
+UINT64
+bid64_from_uint32 (unsigned int x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
+#endif
+  UINT64 res;
+
+  res = x | 0x31c0000000000000ull;	// (exp << 53)) = biased exp. is 0
+  BID_RETURN (res);
+}
+
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid64_from_int64 (UINT64 * pres, SINT64 * px
+		  _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+		  _EXC_INFO_PARAM) {
+  SINT64 x = *px;
+#if !DECIMAL_GLOBAL_ROUNDING
+  unsigned int rnd_mode = *prnd_mode;
+#endif
+#else
+UINT64
+bid64_from_int64 (SINT64 x
+		  _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+		  _EXC_INFO_PARAM) {
+#endif
+
+  UINT64 res;
+  UINT64 x_sign, C;
+  unsigned int q, ind;
+  int incr_exp = 0;
+  int is_midpoint_lt_even = 0, is_midpoint_gt_even = 0;
+  int is_inexact_lt_midpoint = 0, is_inexact_gt_midpoint = 0;
+
+  x_sign = x & 0x8000000000000000ull;
+  // if the integer is negative, use the absolute value
+  if (x_sign)
+    C = ~((UINT64) x) + 1;
+  else
+    C = x;
+  if (C <= BID64_SIG_MAX) {	// |C| <= 10^16-1 and the result is exact
+    if (C < 0x0020000000000000ull) {	// C < 2^53
+      res = x_sign | 0x31c0000000000000ull | C;
+    } else {	// C >= 2^53
+      res =
+	x_sign | 0x6c70000000000000ull | (C & 0x0007ffffffffffffull);
+    }
+  } else {	// |C| >= 10^16 and the result may be inexact 
+    // the smallest |C| is 10^16 which has 17 decimal digits
+    // the largest |C| is 0x8000000000000000 = 9223372036854775808 w/ 19 digits
+    if (C < 0x16345785d8a0000ull) {	// x < 10^17 
+      q = 17;
+      ind = 1;	// number of digits to remove for q = 17
+    } else if (C < 0xde0b6b3a7640000ull) {	// C < 10^18
+      q = 18;
+      ind = 2;	// number of digits to remove for q = 18 
+    } else {	// C < 10^19
+      q = 19;
+      ind = 3;	// number of digits to remove for q = 19
+    }
+    // overflow and underflow are not possible
+    // Note: performace can be improved by inlining this call
+    round64_2_18 (	// will work for 19 digits too if C fits in 64 bits
+		   q, ind, C, &res, &incr_exp,
+		   &is_midpoint_lt_even, &is_midpoint_gt_even,
+		   &is_inexact_lt_midpoint, &is_inexact_gt_midpoint);
+    if (incr_exp)
+      ind++;
+    // set the inexact flag
+    if (is_inexact_lt_midpoint || is_inexact_gt_midpoint ||
+	is_midpoint_lt_even || is_midpoint_gt_even)
+      *pfpsf |= INEXACT_EXCEPTION;
+    // general correction from RN to RA, RM, RP, RZ; result uses ind for exp
+    if (rnd_mode != ROUNDING_TO_NEAREST) {
+      if ((!x_sign
+	   && ((rnd_mode == ROUNDING_UP && is_inexact_lt_midpoint)
+	       ||
+	       ((rnd_mode == ROUNDING_TIES_AWAY
+		 || rnd_mode == ROUNDING_UP) && is_midpoint_gt_even)))
+	  || (x_sign
+	      && ((rnd_mode == ROUNDING_DOWN && is_inexact_lt_midpoint)
+		  ||
+		  ((rnd_mode == ROUNDING_TIES_AWAY
+		    || rnd_mode == ROUNDING_DOWN)
+		   && is_midpoint_gt_even)))) {
+	res = res + 1;
+	if (res == 0x002386f26fc10000ull) {	// res = 10^16 => rounding overflow
+	  res = 0x00038d7ea4c68000ull;	// 10^15
+	  ind = ind + 1;
+	}
+      } else if ((is_midpoint_lt_even || is_inexact_gt_midpoint) &&
+		 ((x_sign && (rnd_mode == ROUNDING_UP ||
+			      rnd_mode == ROUNDING_TO_ZERO)) ||
+		  (!x_sign && (rnd_mode == ROUNDING_DOWN ||
+			       rnd_mode == ROUNDING_TO_ZERO)))) {
+	res = res - 1;
+	// check if we crossed into the lower decade
+	if (res == 0x00038d7ea4c67fffull) {	// 10^15 - 1
+	  res = 0x002386f26fc0ffffull;	// 10^16 - 1
+	  ind = ind - 1;
+	}
+      } else {
+	;	// exact, the result is already correct
+      }
+    }
+    if (res < 0x0020000000000000ull) {	// res < 2^53
+      res = x_sign | (((UINT64) ind + 398) << 53) | res;
+    } else {	// res >= 2^53 
+      res =
+	x_sign | 0x6000000000000000ull | (((UINT64) ind + 398) << 51) |
+	(res & 0x0007ffffffffffffull);
+    }
+  }
+  BID_RETURN (res);
+}
+
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid64_from_uint64 (UINT64 * pres, UINT64 * px
+		   _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+		   _EXC_INFO_PARAM) {
+  UINT64 x = *px;
+#if !DECIMAL_GLOBAL_ROUNDING
+  unsigned int rnd_mode = *prnd_mode;
+#endif
+#else
+UINT64
+bid64_from_uint64 (UINT64 x
+		   _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
+		   _EXC_INFO_PARAM) {
+#endif
+
+  UINT64 res;
+  UINT128 x128, res128;
+  unsigned int q, ind;
+  int incr_exp = 0;
+  int is_midpoint_lt_even = 0, is_midpoint_gt_even = 0;
+  int is_inexact_lt_midpoint = 0, is_inexact_gt_midpoint = 0;
+
+  if (x <= BID64_SIG_MAX) {	// x <= 10^16-1 and the result is exact
+    if (x < 0x0020000000000000ull) {	// x < 2^53
+      res = 0x31c0000000000000ull | x;
+    } else {	// x >= 2^53
+      res = 0x6c70000000000000ull | (x & 0x0007ffffffffffffull);
+    }
+  } else {	// x >= 10^16 and the result may be inexact 
+    // the smallest x is 10^16 which has 17 decimal digits
+    // the largest x is 0xffffffffffffffff = 18446744073709551615 w/ 20 digits
+    if (x < 0x16345785d8a0000ull) {	// x < 10^17 
+      q = 17;
+      ind = 1;	// number of digits to remove for q = 17
+    } else if (x < 0xde0b6b3a7640000ull) {	// x < 10^18
+      q = 18;
+      ind = 2;	// number of digits to remove for q = 18 
+    } else if (x < 0x8ac7230489e80000ull) {	// x < 10^19
+      q = 19;
+      ind = 3;	// number of digits to remove for q = 19
+    } else {	// x < 10^20
+      q = 20;
+      ind = 4;	// number of digits to remove for q = 20
+    }
+    // overflow and underflow are not possible
+    // Note: performace can be improved by inlining this call
+    if (q <= 19) {
+      round64_2_18 (	// will work for 20 digits too if x fits in 64 bits
+		     q, ind, x, &res, &incr_exp,
+		     &is_midpoint_lt_even, &is_midpoint_gt_even,
+		     &is_inexact_lt_midpoint, &is_inexact_gt_midpoint);
+    } else {	// q = 20
+      x128.w[1] = 0x0;
+      x128.w[0] = x;
+      round128_19_38 (q, ind, x128, &res128, &incr_exp,
+		      &is_midpoint_lt_even, &is_midpoint_gt_even,
+		      &is_inexact_lt_midpoint, &is_inexact_gt_midpoint);
+      res = res128.w[0];	// res.w[1] is 0
+    }
+    if (incr_exp)
+      ind++;
+    // set the inexact flag
+    if (is_inexact_lt_midpoint || is_inexact_gt_midpoint ||
+	is_midpoint_lt_even || is_midpoint_gt_even)
+      *pfpsf |= INEXACT_EXCEPTION;
+    // general correction from RN to RA, RM, RP, RZ; result uses ind for exp
+    if (rnd_mode != ROUNDING_TO_NEAREST) {
+      if ((rnd_mode == ROUNDING_UP && is_inexact_lt_midpoint) ||
+	  ((rnd_mode == ROUNDING_TIES_AWAY || rnd_mode == ROUNDING_UP)
+	   && is_midpoint_gt_even)) {
+	res = res + 1;
+	if (res == 0x002386f26fc10000ull) {	// res = 10^16 => rounding overflow
+	  res = 0x00038d7ea4c68000ull;	// 10^15
+	  ind = ind + 1;
+	}
+      } else if ((is_midpoint_lt_even || is_inexact_gt_midpoint) &&
+		 (rnd_mode == ROUNDING_DOWN ||
+		  rnd_mode == ROUNDING_TO_ZERO)) {
+	res = res - 1;
+	// check if we crossed into the lower decade
+	if (res == 0x00038d7ea4c67fffull) {	// 10^15 - 1
+	  res = 0x002386f26fc0ffffull;	// 10^16 - 1
+	  ind = ind - 1;
+	}
+      } else {
+	;	// exact, the result is already correct
+      }
+    }
+    if (res < 0x0020000000000000ull) {	// res < 2^53
+      res = (((UINT64) ind + 398) << 53) | res;
+    } else {	// res >= 2^53 
+      res = 0x6000000000000000ull | (((UINT64) ind + 398) << 51) |
+	(res & 0x0007ffffffffffffull);
+    }
+  }
+  BID_RETURN (res);
+}
+
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid128_from_int32 (UINT128 * pres,
+		   int *px _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
+  int x = *px;
+#else
+UINT128
+bid128_from_int32 (int x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
+#endif
+  UINT128 res;
+
+  // if integer is negative, use the absolute value
+  if ((x & SIGNMASK32) == SIGNMASK32) {
+    res.w[HIGH_128W] = 0xb040000000000000ull;
+    res.w[LOW_128W] = ~((unsigned int) x) + 1;	// 2's complement of x
+  } else {
+    res.w[HIGH_128W] = 0x3040000000000000ull;
+    res.w[LOW_128W] = (unsigned int) x;
+  }
+  BID_RETURN (res);
+}
+
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid128_from_uint32 (UINT128 * pres, unsigned int *px
+		    _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
+  unsigned int x = *px;
+#else
+UINT128
+bid128_from_uint32 (unsigned int x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
+#endif
+  UINT128 res;
+
+  res.w[HIGH_128W] = 0x3040000000000000ull;
+  res.w[LOW_128W] = x;
+  BID_RETURN (res);
+}
+
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid128_from_int64 (UINT128 * pres, SINT64 * px
+		   _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
+  SINT64 x = *px;
+#else
+UINT128
+bid128_from_int64 (SINT64 x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
+#endif
+
+  UINT128 res;
+
+  // if integer is negative, use the absolute value
+  if ((x & SIGNMASK64) == SIGNMASK64) {
+    res.w[HIGH_128W] = 0xb040000000000000ull;
+    res.w[LOW_128W] = ~x + 1;	// 2's complement of x
+  } else {
+    res.w[HIGH_128W] = 0x3040000000000000ull;
+    res.w[LOW_128W] = x;
+  }
+  BID_RETURN (res);
+}
+
+#if DECIMAL_CALL_BY_REFERENCE
+void
+bid128_from_uint64 (UINT128 * pres, UINT64 * px
+		    _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
+  UINT64 x = *px;
+#else
+UINT128
+bid128_from_uint64 (UINT64 x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
+#endif
+
+  UINT128 res;
+
+  res.w[HIGH_128W] = 0x3040000000000000ull;
+  res.w[LOW_128W] = x;
+  BID_RETURN (res);
+}