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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libgcc/config/libbid/bid64_sqrt.c | |
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Diffstat (limited to 'libgcc/config/libbid/bid64_sqrt.c')
-rw-r--r-- | libgcc/config/libbid/bid64_sqrt.c | 552 |
1 files changed, 552 insertions, 0 deletions
diff --git a/libgcc/config/libbid/bid64_sqrt.c b/libgcc/config/libbid/bid64_sqrt.c new file mode 100644 index 000000000..310ab9459 --- /dev/null +++ b/libgcc/config/libbid/bid64_sqrt.c @@ -0,0 +1,552 @@ +/* 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/>. */ + +/***************************************************************************** + * BID64 square root + ***************************************************************************** + * + * Algorithm description: + * + * if(exponent_x is odd) + * scale coefficient_x by 10, adjust exponent + * - get lower estimate for number of digits in coefficient_x + * - scale coefficient x to between 31 and 33 decimal digits + * - in parallel, check for exact case and return if true + * - get high part of result coefficient using double precision sqrt + * - compute remainder and refine coefficient in one iteration (which + * modifies it by at most 1) + * - result exponent is easy to compute from the adjusted arg. exponent + * + ****************************************************************************/ + +#include "bid_internal.h" +#include "bid_sqrt_macros.h" +#ifdef UNCHANGED_BINARY_STATUS_FLAGS +#include <fenv.h> + +#define FE_ALL_FLAGS FE_INVALID|FE_DIVBYZERO|FE_OVERFLOW|FE_UNDERFLOW|FE_INEXACT +#endif + +extern double sqrt (double); + +#if DECIMAL_CALL_BY_REFERENCE + +void +bid64_sqrt (UINT64 * pres, + UINT64 * + px _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM + _EXC_INFO_PARAM) { + UINT64 x; +#else + +UINT64 +bid64_sqrt (UINT64 x _RND_MODE_PARAM _EXC_FLAGS_PARAM + _EXC_MASKS_PARAM _EXC_INFO_PARAM) { +#endif + UINT128 CA, CT; + UINT64 sign_x, coefficient_x; + UINT64 Q, Q2, A10, C4, R, R2, QE, res; + SINT64 D; + int_double t_scale; + int_float tempx; + double da, dq, da_h, da_l, dqe; + int exponent_x, exponent_q, bin_expon_cx; + int digits_x; + int scale; +#ifdef UNCHANGED_BINARY_STATUS_FLAGS + fexcept_t binaryflags = 0; +#endif + +#if DECIMAL_CALL_BY_REFERENCE +#if !DECIMAL_GLOBAL_ROUNDING + _IDEC_round rnd_mode = *prnd_mode; +#endif + x = *px; +#endif + + // unpack arguments, check for NaN or Infinity + if (!unpack_BID64 (&sign_x, &exponent_x, &coefficient_x, x)) { + // x is Inf. or NaN or 0 + if ((x & INFINITY_MASK64) == INFINITY_MASK64) { + res = coefficient_x; + if ((coefficient_x & SSNAN_MASK64) == SINFINITY_MASK64) // -Infinity + { + res = NAN_MASK64; +#ifdef SET_STATUS_FLAGS + __set_status_flags (pfpsf, INVALID_EXCEPTION); +#endif + } +#ifdef SET_STATUS_FLAGS + if ((x & SNAN_MASK64) == SNAN_MASK64) // sNaN + __set_status_flags (pfpsf, INVALID_EXCEPTION); +#endif + BID_RETURN (res & QUIET_MASK64); + } + // x is 0 + exponent_x = (exponent_x + DECIMAL_EXPONENT_BIAS) >> 1; + res = sign_x | (((UINT64) exponent_x) << 53); + BID_RETURN (res); + } + // x<0? + if (sign_x && coefficient_x) { + res = NAN_MASK64; +#ifdef SET_STATUS_FLAGS + __set_status_flags (pfpsf, INVALID_EXCEPTION); +#endif + BID_RETURN (res); + } +#ifdef UNCHANGED_BINARY_STATUS_FLAGS + (void) fegetexceptflag (&binaryflags, FE_ALL_FLAGS); +#endif + //--- get number of bits in the coefficient of x --- + tempx.d = (float) coefficient_x; + bin_expon_cx = ((tempx.i >> 23) & 0xff) - 0x7f; + digits_x = estimate_decimal_digits[bin_expon_cx]; + // add test for range + if (coefficient_x >= power10_index_binexp[bin_expon_cx]) + digits_x++; + + A10 = coefficient_x; + if (exponent_x & 1) { + A10 = (A10 << 2) + A10; + A10 += A10; + } + + dqe = sqrt ((double) A10); + QE = (UINT32) dqe; + if (QE * QE == A10) { + res = + very_fast_get_BID64 (0, (exponent_x + DECIMAL_EXPONENT_BIAS) >> 1, + QE); +#ifdef UNCHANGED_BINARY_STATUS_FLAGS + (void) fesetexceptflag (&binaryflags, FE_ALL_FLAGS); +#endif + BID_RETURN (res); + } + // if exponent is odd, scale coefficient by 10 + scale = 31 - digits_x; + exponent_q = exponent_x - scale; + scale += (exponent_q & 1); // exp. bias is even + + CT = power10_table_128[scale]; + __mul_64x128_short (CA, coefficient_x, CT); + + // 2^64 + t_scale.i = 0x43f0000000000000ull; + // convert CA to DP + da_h = CA.w[1]; + da_l = CA.w[0]; + da = da_h * t_scale.d + da_l; + + dq = sqrt (da); + + Q = (UINT64) dq; + + // get sign(sqrt(CA)-Q) + R = CA.w[0] - Q * Q; + R = ((SINT64) R) >> 63; + D = R + R + 1; + + exponent_q = (exponent_q + DECIMAL_EXPONENT_BIAS) >> 1; + +#ifdef SET_STATUS_FLAGS + __set_status_flags (pfpsf, INEXACT_EXCEPTION); +#endif + +#ifndef IEEE_ROUND_NEAREST +#ifndef IEEE_ROUND_NEAREST_TIES_AWAY + if (!((rnd_mode) & 3)) { +#endif +#endif + + // midpoint to check + Q2 = Q + Q + D; + C4 = CA.w[0] << 2; + + // get sign(-sqrt(CA)+Midpoint) + R2 = Q2 * Q2 - C4; + R2 = ((SINT64) R2) >> 63; + + // adjust Q if R!=R2 + Q += (D & (R ^ R2)); +#ifndef IEEE_ROUND_NEAREST +#ifndef IEEE_ROUND_NEAREST_TIES_AWAY + } else { + C4 = CA.w[0]; + Q += D; + if ((SINT64) (Q * Q - C4) > 0) + Q--; + if (rnd_mode == ROUNDING_UP) + Q++; + } +#endif +#endif + + res = fast_get_BID64 (0, exponent_q, Q); +#ifdef UNCHANGED_BINARY_STATUS_FLAGS + (void) fesetexceptflag (&binaryflags, FE_ALL_FLAGS); +#endif + BID_RETURN (res); +} + + +TYPE0_FUNCTION_ARG1 (UINT64, bid64q_sqrt, x) + + UINT256 M256, C4, C8; + UINT128 CX, CX2, A10, S2, T128, CS, CSM, CS2, C256, CS1, + mul_factor2_long = { {0x0ull, 0x0ull} }, QH, Tmp, TP128, Qh, Ql; +UINT64 sign_x, Carry, B10, res, mul_factor, mul_factor2 = 0x0ull, CS0; +SINT64 D; +int_float fx, f64; +int exponent_x, bin_expon_cx, done = 0; +int digits, scale, exponent_q = 0, exact = 1, amount, extra_digits; +#ifdef UNCHANGED_BINARY_STATUS_FLAGS +fexcept_t binaryflags = 0; +#endif + + // unpack arguments, check for NaN or Infinity +if (!unpack_BID128_value (&sign_x, &exponent_x, &CX, x)) { + res = CX.w[1]; + // NaN ? + if ((x.w[1] & 0x7c00000000000000ull) == 0x7c00000000000000ull) { +#ifdef SET_STATUS_FLAGS + if ((x.w[1] & 0x7e00000000000000ull) == 0x7e00000000000000ull) // sNaN + __set_status_flags (pfpsf, INVALID_EXCEPTION); +#endif + Tmp.w[1] = (CX.w[1] & 0x00003fffffffffffull); + Tmp.w[0] = CX.w[0]; + TP128 = reciprocals10_128[18]; + __mul_128x128_full (Qh, Ql, Tmp, TP128); + amount = recip_scale[18]; + __shr_128 (Tmp, Qh, amount); + res = (CX.w[1] & 0xfc00000000000000ull) | Tmp.w[0]; + BID_RETURN (res); + } + // x is Infinity? + if ((x.w[1] & 0x7800000000000000ull) == 0x7800000000000000ull) { + if (sign_x) { + // -Inf, return NaN + res = 0x7c00000000000000ull; +#ifdef SET_STATUS_FLAGS + __set_status_flags (pfpsf, INVALID_EXCEPTION); +#endif + } + BID_RETURN (res); + } + // x is 0 otherwise + + exponent_x = + ((exponent_x - DECIMAL_EXPONENT_BIAS_128) >> 1) + + DECIMAL_EXPONENT_BIAS; + if (exponent_x < 0) + exponent_x = 0; + if (exponent_x > DECIMAL_MAX_EXPON_64) + exponent_x = DECIMAL_MAX_EXPON_64; + //res= sign_x | (((UINT64)exponent_x)<<53); + res = get_BID64 (sign_x, exponent_x, 0, rnd_mode, pfpsf); + BID_RETURN (res); +} +if (sign_x) { + res = 0x7c00000000000000ull; +#ifdef SET_STATUS_FLAGS + __set_status_flags (pfpsf, INVALID_EXCEPTION); +#endif + BID_RETURN (res); +} +#ifdef UNCHANGED_BINARY_STATUS_FLAGS +(void) fegetexceptflag (&binaryflags, FE_ALL_FLAGS); +#endif + + // 2^64 +f64.i = 0x5f800000; + + // fx ~ CX +fx.d = (float) CX.w[1] * f64.d + (float) CX.w[0]; +bin_expon_cx = ((fx.i >> 23) & 0xff) - 0x7f; +digits = estimate_decimal_digits[bin_expon_cx]; + +A10 = CX; +if (exponent_x & 1) { + A10.w[1] = (CX.w[1] << 3) | (CX.w[0] >> 61); + A10.w[0] = CX.w[0] << 3; + CX2.w[1] = (CX.w[1] << 1) | (CX.w[0] >> 63); + CX2.w[0] = CX.w[0] << 1; + __add_128_128 (A10, A10, CX2); +} + +C256.w[1] = A10.w[1]; +C256.w[0] = A10.w[0]; +CS.w[0] = short_sqrt128 (A10); +CS.w[1] = 0; +mul_factor = 0; + // check for exact result +if (CS.w[0] < 10000000000000000ull) { + if (CS.w[0] * CS.w[0] == A10.w[0]) { + __sqr64_fast (S2, CS.w[0]); + if (S2.w[1] == A10.w[1]) // && S2.w[0]==A10.w[0]) + { + res = + get_BID64 (0, + ((exponent_x - DECIMAL_EXPONENT_BIAS_128) >> 1) + + DECIMAL_EXPONENT_BIAS, CS.w[0], rnd_mode, pfpsf); +#ifdef UNCHANGED_BINARY_STATUS_FLAGS + (void) fesetexceptflag (&binaryflags, FE_ALL_FLAGS); +#endif + BID_RETURN (res); + } + } + if (CS.w[0] >= 1000000000000000ull) { + done = 1; + exponent_q = exponent_x; + C256.w[1] = A10.w[1]; + C256.w[0] = A10.w[0]; + } +#ifdef SET_STATUS_FLAGS + __set_status_flags (pfpsf, INEXACT_EXCEPTION); +#endif + exact = 0; +} else { + B10 = 0x3333333333333334ull; + __mul_64x64_to_128_full (CS2, CS.w[0], B10); + CS0 = CS2.w[1] >> 1; + if (CS.w[0] != ((CS0 << 3) + (CS0 << 1))) { +#ifdef SET_STATUS_FLAGS + __set_status_flags (pfpsf, INEXACT_EXCEPTION); +#endif + exact = 0; + } + done = 1; + CS.w[0] = CS0; + exponent_q = exponent_x + 2; + mul_factor = 10; + mul_factor2 = 100; + if (CS.w[0] >= 10000000000000000ull) { + __mul_64x64_to_128_full (CS2, CS.w[0], B10); + CS0 = CS2.w[1] >> 1; + if (CS.w[0] != ((CS0 << 3) + (CS0 << 1))) { +#ifdef SET_STATUS_FLAGS + __set_status_flags (pfpsf, INEXACT_EXCEPTION); +#endif + exact = 0; + } + exponent_q += 2; + CS.w[0] = CS0; + mul_factor = 100; + mul_factor2 = 10000; + } + if (exact) { + CS0 = CS.w[0] * mul_factor; + __sqr64_fast (CS1, CS0) + if ((CS1.w[0] != A10.w[0]) || (CS1.w[1] != A10.w[1])) { +#ifdef SET_STATUS_FLAGS + __set_status_flags (pfpsf, INEXACT_EXCEPTION); +#endif + exact = 0; + } + } +} + +if (!done) { + // get number of digits in CX + D = CX.w[1] - power10_index_binexp_128[bin_expon_cx].w[1]; + if (D > 0 + || (!D && CX.w[0] >= power10_index_binexp_128[bin_expon_cx].w[0])) + digits++; + + // if exponent is odd, scale coefficient by 10 + scale = 31 - digits; + exponent_q = exponent_x - scale; + scale += (exponent_q & 1); // exp. bias is even + + T128 = power10_table_128[scale]; + __mul_128x128_low (C256, CX, T128); + + + CS.w[0] = short_sqrt128 (C256); +} + //printf("CS=%016I64x\n",CS.w[0]); + +exponent_q = + ((exponent_q - DECIMAL_EXPONENT_BIAS_128) >> 1) + + DECIMAL_EXPONENT_BIAS; +if ((exponent_q < 0) && (exponent_q + MAX_FORMAT_DIGITS >= 0)) { + extra_digits = -exponent_q; + exponent_q = 0; + + // get coeff*(2^M[extra_digits])/10^extra_digits + __mul_64x64_to_128 (QH, CS.w[0], reciprocals10_64[extra_digits]); + + // now get P/10^extra_digits: shift Q_high right by M[extra_digits]-128 + amount = short_recip_scale[extra_digits]; + + CS0 = QH.w[1] >> amount; + +#ifdef SET_STATUS_FLAGS + if (exact) { + if (CS.w[0] != CS0 * power10_table_128[extra_digits].w[0]) + exact = 0; + } + if (!exact) + __set_status_flags (pfpsf, UNDERFLOW_EXCEPTION | INEXACT_EXCEPTION); +#endif + + CS.w[0] = CS0; + if (!mul_factor) + mul_factor = 1; + mul_factor *= power10_table_128[extra_digits].w[0]; + __mul_64x64_to_128 (mul_factor2_long, mul_factor, mul_factor); + if (mul_factor2_long.w[1]) + mul_factor2 = 0; + else + mul_factor2 = mul_factor2_long.w[1]; +} + // 4*C256 +C4.w[1] = (C256.w[1] << 2) | (C256.w[0] >> 62); +C4.w[0] = C256.w[0] << 2; + +#ifndef IEEE_ROUND_NEAREST +#ifndef IEEE_ROUND_NEAREST_TIES_AWAY +if (!((rnd_mode) & 3)) { +#endif +#endif + // compare to midpoints + CSM.w[0] = (CS.w[0] + CS.w[0]) | 1; + //printf("C256=%016I64x %016I64x, CSM=%016I64x %016I64x %016I64x\n",C4.w[1],C4.w[0],CSM.w[1],CSM.w[0], CS.w[0]); + if (mul_factor) + CSM.w[0] *= mul_factor; + // CSM^2 + __mul_64x64_to_128 (M256, CSM.w[0], CSM.w[0]); + //__mul_128x128_to_256(M256, CSM, CSM); + + if (C4.w[1] > M256.w[1] || + (C4.w[1] == M256.w[1] && C4.w[0] > M256.w[0])) { + // round up + CS.w[0]++; + } else { + C8.w[0] = CS.w[0] << 3; + C8.w[1] = 0; + if (mul_factor) { + if (mul_factor2) { + __mul_64x64_to_128 (C8, C8.w[0], mul_factor2); + } else { + __mul_64x128_low (C8, C8.w[0], mul_factor2_long); + } + } + // M256 - 8*CSM + __sub_borrow_out (M256.w[0], Carry, M256.w[0], C8.w[0]); + M256.w[1] = M256.w[1] - C8.w[1] - Carry; + + // if CSM' > C256, round up + if (M256.w[1] > C4.w[1] || + (M256.w[1] == C4.w[1] && M256.w[0] > C4.w[0])) { + // round down + if (CS.w[0]) + CS.w[0]--; + } + } +#ifndef IEEE_ROUND_NEAREST +#ifndef IEEE_ROUND_NEAREST_TIES_AWAY +} else { + CS.w[0]++; + CSM.w[0] = CS.w[0]; + C8.w[0] = CSM.w[0] << 1; + if (mul_factor) + CSM.w[0] *= mul_factor; + __mul_64x64_to_128 (M256, CSM.w[0], CSM.w[0]); + C8.w[1] = 0; + if (mul_factor) { + if (mul_factor2) { + __mul_64x64_to_128 (C8, C8.w[0], mul_factor2); + } else { + __mul_64x128_low (C8, C8.w[0], mul_factor2_long); + } + } + //printf("C256=%016I64x %016I64x, CSM=%016I64x %016I64x %016I64x\n",C256.w[1],C256.w[0],M256.w[1],M256.w[0], CS.w[0]); + + if (M256.w[1] > C256.w[1] || + (M256.w[1] == C256.w[1] && M256.w[0] > C256.w[0])) { + __sub_borrow_out (M256.w[0], Carry, M256.w[0], C8.w[0]); + M256.w[1] = M256.w[1] - Carry - C8.w[1]; + M256.w[0]++; + if (!M256.w[0]) { + M256.w[1]++; + + } + + if ((M256.w[1] > C256.w[1] || + (M256.w[1] == C256.w[1] && M256.w[0] > C256.w[0])) + && (CS.w[0] > 1)) { + + CS.w[0]--; + + if (CS.w[0] > 1) { + __sub_borrow_out (M256.w[0], Carry, M256.w[0], C8.w[0]); + M256.w[1] = M256.w[1] - Carry - C8.w[1]; + M256.w[0]++; + if (!M256.w[0]) { + M256.w[1]++; + } + + if (M256.w[1] > C256.w[1] || + (M256.w[1] == C256.w[1] && M256.w[0] > C256.w[0])) + CS.w[0]--; + } + } + } + + else { + /*__add_carry_out(M256.w[0], Carry, M256.w[0], C8.w[0]); + M256.w[1] = M256.w[1] + Carry + C8.w[1]; + M256.w[0]++; + if(!M256.w[0]) + { + M256.w[1]++; + } + CS.w[0]++; + if(M256.w[1]<C256.w[1] || + (M256.w[1]==C256.w[1] && M256.w[0]<=C256.w[0])) + { + CS.w[0]++; + }*/ + CS.w[0]++; + } + //printf("C256=%016I64x %016I64x, CSM=%016I64x %016I64x %016I64x %d\n",C4.w[1],C4.w[0],M256.w[1],M256.w[0], CS.w[0], exact); + // RU? + if (((rnd_mode) != ROUNDING_UP) || exact) { + if (CS.w[0]) + CS.w[0]--; + } + +} +#endif +#endif + //printf("C256=%016I64x %016I64x, CSM=%016I64x %016I64x %016I64x %d\n",C4.w[1],C4.w[0],M256.w[1],M256.w[0], CS.w[0], exact); + +res = get_BID64 (0, exponent_q, CS.w[0], rnd_mode, pfpsf); +#ifdef UNCHANGED_BINARY_STATUS_FLAGS +(void) fesetexceptflag (&binaryflags, FE_ALL_FLAGS); +#endif +BID_RETURN (res); + + +} |