libgcc/config/libbid/bid64_quantize.c - rust-lang/gcc - Git at Google

 /* Copyright (C) 2007-2020 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"

 #define MAX_FORMAT_DIGITS     16
 #define DECIMAL_EXPONENT_BIAS 398
 #define MAX_DECIMAL_EXPONENT  767

 #if DECIMAL_CALL_BY_REFERENCE

 void
 bid64_quantize (UINT64 * pres, UINT64 * px,
 		UINT64 *
 		py _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
 		_EXC_INFO_PARAM) {
   UINT64 x, y;
 #else

 UINT64
 bid64_quantize (UINT64 x,
 		UINT64 y _RND_MODE_PARAM _EXC_FLAGS_PARAM
 		_EXC_MASKS_PARAM _EXC_INFO_PARAM) {
 #endif
   UINT128 CT;
   UINT64 sign_x, sign_y, coefficient_x, coefficient_y, remainder_h, C64,
     valid_x;
   UINT64 tmp, carry, res;
   int_float tempx;
   int exponent_x, exponent_y, digits_x, extra_digits, amount, amount2;
   int expon_diff, total_digits, bin_expon_cx;
   unsigned rmode, status;

 #if DECIMAL_CALL_BY_REFERENCE
 #if !DECIMAL_GLOBAL_ROUNDING
   _IDEC_round rnd_mode = *prnd_mode;
 #endif
   x = *px;
   y = *py;
 #endif

   valid_x = unpack_BID64 (&sign_x, &exponent_x, &coefficient_x, x);
   // unpack arguments, check for NaN or Infinity
   if (!unpack_BID64 (&sign_y, &exponent_y, &coefficient_y, y)) {
     // Inf. or NaN or 0
 #ifdef SET_STATUS_FLAGS
     if ((x & SNAN_MASK64) == SNAN_MASK64)	// y is sNaN
       __set_status_flags (pfpsf, INVALID_EXCEPTION);
 #endif

     // x=Inf, y=Inf?
     if (((coefficient_x << 1) == 0xf000000000000000ull)
 	&& ((coefficient_y << 1) == 0xf000000000000000ull)) {
       res = coefficient_x;
       BID_RETURN (res);
     }
     // Inf or NaN?
     if ((y & 0x7800000000000000ull) == 0x7800000000000000ull) {
 #ifdef SET_STATUS_FLAGS
       if (((y & 0x7e00000000000000ull) == 0x7e00000000000000ull)	// sNaN
 	  || (((y & 0x7c00000000000000ull) == 0x7800000000000000ull) &&	//Inf
 	      ((x & 0x7c00000000000000ull) < 0x7800000000000000ull)))
 	__set_status_flags (pfpsf, INVALID_EXCEPTION);
 #endif
       if ((y & NAN_MASK64) != NAN_MASK64)
 	coefficient_y = 0;
       if ((x & NAN_MASK64) != NAN_MASK64) {
 	res = 0x7c00000000000000ull | (coefficient_y & QUIET_MASK64);
 	if (((y & NAN_MASK64) != NAN_MASK64) && ((x & NAN_MASK64) == 0x7800000000000000ull))
 		res = x;
 	BID_RETURN (res);
       }
     }
   }
   // unpack arguments, check for NaN or Infinity
   if (!valid_x) {
     // x is Inf. or NaN or 0

     // Inf or NaN?
     if ((x & 0x7800000000000000ull) == 0x7800000000000000ull) {
 #ifdef SET_STATUS_FLAGS
       if (((x & 0x7e00000000000000ull) == 0x7e00000000000000ull)	// sNaN
 	  || ((x & 0x7c00000000000000ull) == 0x7800000000000000ull))	//Inf
 	__set_status_flags (pfpsf, INVALID_EXCEPTION);
 #endif
       if ((x & NAN_MASK64) != NAN_MASK64)
 	coefficient_x = 0;
       res = 0x7c00000000000000ull | (coefficient_x & QUIET_MASK64);
       BID_RETURN (res);
     }

     res = very_fast_get_BID64_small_mantissa (sign_x, exponent_y, 0);
     BID_RETURN (res);
   }
   // get number of decimal digits in coefficient_x
   tempx.d = (float) coefficient_x;
   bin_expon_cx = ((tempx.i >> 23) & 0xff) - 0x7f;
   digits_x = estimate_decimal_digits[bin_expon_cx];
   if (coefficient_x >= power10_table_128[digits_x].w[0])
     digits_x++;

   expon_diff = exponent_x - exponent_y;
   total_digits = digits_x + expon_diff;

   // check range of scaled coefficient
   if ((UINT32) (total_digits + 1) <= 17) {
     if (expon_diff >= 0) {
       coefficient_x *= power10_table_128[expon_diff].w[0];
       res = very_fast_get_BID64 (sign_x, exponent_y, coefficient_x);
       BID_RETURN (res);
     }
     // must round off -expon_diff digits
     extra_digits = -expon_diff;
 #ifndef IEEE_ROUND_NEAREST_TIES_AWAY
 #ifndef IEEE_ROUND_NEAREST
     rmode = rnd_mode;
     if (sign_x && (unsigned) (rmode - 1) < 2)
       rmode = 3 - rmode;
 #else
     rmode = 0;
 #endif
 #else
     rmode = 0;
 #endif
     coefficient_x += round_const_table[rmode][extra_digits];

     // get P*(2^M[extra_digits])/10^extra_digits
     __mul_64x64_to_128 (CT, coefficient_x,
 			reciprocals10_64[extra_digits]);

     // now get P/10^extra_digits: shift C64 right by M[extra_digits]-128
     amount = short_recip_scale[extra_digits];
     C64 = CT.w[1] >> amount;
 #ifndef IEEE_ROUND_NEAREST_TIES_AWAY
 #ifndef IEEE_ROUND_NEAREST
     if (rnd_mode == 0)
 #endif
       if (C64 & 1) {
 	// check whether fractional part of initial_P/10^extra_digits
 	// is exactly .5
 	// this is the same as fractional part of
 	//   (initial_P + 0.5*10^extra_digits)/10^extra_digits is exactly zero

 	// get remainder
 	amount2 = 64 - amount;
 	remainder_h = 0;
 	remainder_h--;
 	remainder_h >>= amount2;
 	remainder_h = remainder_h & CT.w[1];

 	// test whether fractional part is 0
 	if (!remainder_h && (CT.w[0] < reciprocals10_64[extra_digits])) {
 	  C64--;
 	}
       }
 #endif

 #ifdef SET_STATUS_FLAGS
     status = INEXACT_EXCEPTION;
     // get remainder
     remainder_h = CT.w[1] << (64 - amount);
     switch (rmode) {
     case ROUNDING_TO_NEAREST:
     case ROUNDING_TIES_AWAY:
       // test whether fractional part is 0
       if ((remainder_h == 0x8000000000000000ull)
 	  && (CT.w[0] < reciprocals10_64[extra_digits]))
 	status = EXACT_STATUS;
       break;
     case ROUNDING_DOWN:
     case ROUNDING_TO_ZERO:
       if (!remainder_h && (CT.w[0] < reciprocals10_64[extra_digits]))
 	status = EXACT_STATUS;
       //if(!C64 && rmode==ROUNDING_DOWN) sign_s=sign_y;
       break;
     default:
       // round up
       __add_carry_out (tmp, carry, CT.w[0],
 		       reciprocals10_64[extra_digits]);
       if ((remainder_h >> (64 - amount)) + carry >=
 	  (((UINT64) 1) << amount))
 	status = EXACT_STATUS;
       break;
     }
     __set_status_flags (pfpsf, status);
 #endif

     res = very_fast_get_BID64_small_mantissa (sign_x, exponent_y, C64);
     BID_RETURN (res);
   }

   if (total_digits < 0) {
 #ifdef SET_STATUS_FLAGS
     __set_status_flags (pfpsf, INEXACT_EXCEPTION);
 #endif
     C64 = 0;
 #ifndef IEEE_ROUND_NEAREST_TIES_AWAY
 #ifndef IEEE_ROUND_NEAREST
     rmode = rnd_mode;
     if (sign_x && (unsigned) (rmode - 1) < 2)
       rmode = 3 - rmode;
     if (rmode == ROUNDING_UP)
       C64 = 1;
 #endif
 #endif
     res = very_fast_get_BID64_small_mantissa (sign_x, exponent_y, C64);
     BID_RETURN (res);
   }
   // else  more than 16 digits in coefficient
 #ifdef SET_STATUS_FLAGS
   __set_status_flags (pfpsf, INVALID_EXCEPTION);
 #endif
   res = 0x7c00000000000000ull;
   BID_RETURN (res);

 }
	/* Copyright (C) 2007-2020 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"

	#define MAX_FORMAT_DIGITS 16
	#define DECIMAL_EXPONENT_BIAS 398
	#define MAX_DECIMAL_EXPONENT 767

	#if DECIMAL_CALL_BY_REFERENCE

	void
	bid64_quantize (UINT64 * pres, UINT64 * px,
	UINT64 *
	py _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
	_EXC_INFO_PARAM) {
	UINT64 x, y;
	#else

	UINT64
	bid64_quantize (UINT64 x,
	UINT64 y _RND_MODE_PARAM _EXC_FLAGS_PARAM
	_EXC_MASKS_PARAM _EXC_INFO_PARAM) {
	#endif
	UINT128 CT;
	UINT64 sign_x, sign_y, coefficient_x, coefficient_y, remainder_h, C64,
	valid_x;
	UINT64 tmp, carry, res;
	int_float tempx;
	int exponent_x, exponent_y, digits_x, extra_digits, amount, amount2;
	int expon_diff, total_digits, bin_expon_cx;
	unsigned rmode, status;

	#if DECIMAL_CALL_BY_REFERENCE
	#if !DECIMAL_GLOBAL_ROUNDING
	_IDEC_round rnd_mode = *prnd_mode;
	#endif
	x = *px;
	y = *py;
	#endif

	valid_x = unpack_BID64 (&sign_x, &exponent_x, &coefficient_x, x);
	// unpack arguments, check for NaN or Infinity
	if (!unpack_BID64 (&sign_y, &exponent_y, &coefficient_y, y)) {
	// Inf. or NaN or 0
	#ifdef SET_STATUS_FLAGS
	if ((x & SNAN_MASK64) == SNAN_MASK64) // y is sNaN
	__set_status_flags (pfpsf, INVALID_EXCEPTION);
	#endif

	// x=Inf, y=Inf?
	if (((coefficient_x << 1) == 0xf000000000000000ull)
	&& ((coefficient_y << 1) == 0xf000000000000000ull)) {
	res = coefficient_x;
	BID_RETURN (res);
	}
	// Inf or NaN?
	if ((y & 0x7800000000000000ull) == 0x7800000000000000ull) {
	#ifdef SET_STATUS_FLAGS
	if (((y & 0x7e00000000000000ull) == 0x7e00000000000000ull) // sNaN
	\|\| (((y & 0x7c00000000000000ull) == 0x7800000000000000ull) && //Inf
	((x & 0x7c00000000000000ull) < 0x7800000000000000ull)))
	__set_status_flags (pfpsf, INVALID_EXCEPTION);
	#endif
	if ((y & NAN_MASK64) != NAN_MASK64)
	coefficient_y = 0;
	if ((x & NAN_MASK64) != NAN_MASK64) {
	res = 0x7c00000000000000ull \| (coefficient_y & QUIET_MASK64);
	if (((y & NAN_MASK64) != NAN_MASK64) && ((x & NAN_MASK64) == 0x7800000000000000ull))
	res = x;
	BID_RETURN (res);
	}
	}
	}
	// unpack arguments, check for NaN or Infinity
	if (!valid_x) {
	// x is Inf. or NaN or 0

	// Inf or NaN?
	if ((x & 0x7800000000000000ull) == 0x7800000000000000ull) {
	#ifdef SET_STATUS_FLAGS
	if (((x & 0x7e00000000000000ull) == 0x7e00000000000000ull) // sNaN
	\|\| ((x & 0x7c00000000000000ull) == 0x7800000000000000ull)) //Inf
	__set_status_flags (pfpsf, INVALID_EXCEPTION);
	#endif
	if ((x & NAN_MASK64) != NAN_MASK64)
	coefficient_x = 0;
	res = 0x7c00000000000000ull \| (coefficient_x & QUIET_MASK64);
	BID_RETURN (res);
	}

	res = very_fast_get_BID64_small_mantissa (sign_x, exponent_y, 0);
	BID_RETURN (res);
	}
	// get number of decimal digits in coefficient_x
	tempx.d = (float) coefficient_x;
	bin_expon_cx = ((tempx.i >> 23) & 0xff) - 0x7f;
	digits_x = estimate_decimal_digits[bin_expon_cx];
	if (coefficient_x >= power10_table_128[digits_x].w[0])
	digits_x++;

	expon_diff = exponent_x - exponent_y;
	total_digits = digits_x + expon_diff;

	// check range of scaled coefficient
	if ((UINT32) (total_digits + 1) <= 17) {
	if (expon_diff >= 0) {
	coefficient_x *= power10_table_128[expon_diff].w[0];
	res = very_fast_get_BID64 (sign_x, exponent_y, coefficient_x);
	BID_RETURN (res);
	}
	// must round off -expon_diff digits
	extra_digits = -expon_diff;
	#ifndef IEEE_ROUND_NEAREST_TIES_AWAY
	#ifndef IEEE_ROUND_NEAREST
	rmode = rnd_mode;
	if (sign_x && (unsigned) (rmode - 1) < 2)
	rmode = 3 - rmode;
	#else
	rmode = 0;
	#endif
	#else
	rmode = 0;
	#endif
	coefficient_x += round_const_table[rmode][extra_digits];

	// get P*(2^M[extra_digits])/10^extra_digits
	__mul_64x64_to_128 (CT, coefficient_x,
	reciprocals10_64[extra_digits]);

	// now get P/10^extra_digits: shift C64 right by M[extra_digits]-128
	amount = short_recip_scale[extra_digits];
	C64 = CT.w[1] >> amount;
	#ifndef IEEE_ROUND_NEAREST_TIES_AWAY
	#ifndef IEEE_ROUND_NEAREST
	if (rnd_mode == 0)
	#endif
	if (C64 & 1) {
	// check whether fractional part of initial_P/10^extra_digits
	// is exactly .5
	// this is the same as fractional part of
	// (initial_P + 0.5*10^extra_digits)/10^extra_digits is exactly zero

	// get remainder
	amount2 = 64 - amount;
	remainder_h = 0;
	remainder_h--;
	remainder_h >>= amount2;
	remainder_h = remainder_h & CT.w[1];

	// test whether fractional part is 0
	if (!remainder_h && (CT.w[0] < reciprocals10_64[extra_digits])) {
	C64--;
	}
	}
	#endif

	#ifdef SET_STATUS_FLAGS
	status = INEXACT_EXCEPTION;
	// get remainder
	remainder_h = CT.w[1] << (64 - amount);
	switch (rmode) {
	case ROUNDING_TO_NEAREST:
	case ROUNDING_TIES_AWAY:
	// test whether fractional part is 0
	if ((remainder_h == 0x8000000000000000ull)
	&& (CT.w[0] < reciprocals10_64[extra_digits]))
	status = EXACT_STATUS;
	break;
	case ROUNDING_DOWN:
	case ROUNDING_TO_ZERO:
	if (!remainder_h && (CT.w[0] < reciprocals10_64[extra_digits]))
	status = EXACT_STATUS;
	//if(!C64 && rmode==ROUNDING_DOWN) sign_s=sign_y;
	break;
	default:
	// round up
	__add_carry_out (tmp, carry, CT.w[0],
	reciprocals10_64[extra_digits]);
	if ((remainder_h >> (64 - amount)) + carry >=
	(((UINT64) 1) << amount))
	status = EXACT_STATUS;
	break;
	}
	__set_status_flags (pfpsf, status);
	#endif

	res = very_fast_get_BID64_small_mantissa (sign_x, exponent_y, C64);
	BID_RETURN (res);
	}

	if (total_digits < 0) {
	#ifdef SET_STATUS_FLAGS
	__set_status_flags (pfpsf, INEXACT_EXCEPTION);
	#endif
	C64 = 0;
	#ifndef IEEE_ROUND_NEAREST_TIES_AWAY
	#ifndef IEEE_ROUND_NEAREST
	rmode = rnd_mode;
	if (sign_x && (unsigned) (rmode - 1) < 2)
	rmode = 3 - rmode;
	if (rmode == ROUNDING_UP)
	C64 = 1;
	#endif
	#endif
	res = very_fast_get_BID64_small_mantissa (sign_x, exponent_y, C64);
	BID_RETURN (res);
	}
	// else more than 16 digits in coefficient
	#ifdef SET_STATUS_FLAGS
	__set_status_flags (pfpsf, INVALID_EXCEPTION);
	#endif
	res = 0x7c00000000000000ull;
	BID_RETURN (res);

	}