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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.5.1/] [libgcc/] [config/] [libbid/] [bid64_string.c] - Rev 272
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/* 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 <ctype.h> #include "bid_internal.h" #include "bid128_2_str.h" #include "bid128_2_str_macros.h" #define MAX_FORMAT_DIGITS 16 #define DECIMAL_EXPONENT_BIAS 398 #define MAX_DECIMAL_EXPONENT 767 #if DECIMAL_CALL_BY_REFERENCE void bid64_to_string (char *ps, UINT64 * px _EXC_FLAGS_PARAM _EXC_MASKS_PARAM _EXC_INFO_PARAM) { UINT64 x; #else void bid64_to_string (char *ps, UINT64 x _EXC_FLAGS_PARAM _EXC_MASKS_PARAM _EXC_INFO_PARAM) { #endif // the destination string (pointed to by ps) must be pre-allocated UINT64 sign_x, coefficient_x, D, ER10; int istart, exponent_x, j, digits_x, bin_expon_cx; int_float tempx; UINT32 MiDi[12], *ptr; UINT64 HI_18Dig, LO_18Dig, Tmp; char *c_ptr_start, *c_ptr; int midi_ind, k_lcv, len; unsigned int save_fpsf; #if DECIMAL_CALL_BY_REFERENCE x = *px; #endif save_fpsf = *pfpsf; // place holder only // unpack arguments, check for NaN or Infinity if (!unpack_BID64 (&sign_x, &exponent_x, &coefficient_x, x)) { // x is Inf. or NaN or 0 // Inf or NaN? if ((x & 0x7800000000000000ull) == 0x7800000000000000ull) { if ((x & 0x7c00000000000000ull) == 0x7c00000000000000ull) { ps[0] = (sign_x) ? '-' : '+'; ps[1] = ((x & MASK_SNAN) == MASK_SNAN)? 'S':'Q'; ps[2] = 'N'; ps[3] = 'a'; ps[4] = 'N'; ps[5] = 0; return; } // x is Inf ps[0] = (sign_x) ? '-' : '+'; ps[1] = 'I'; ps[2] = 'n'; ps[3] = 'f'; ps[4] = 0; return; } // 0 istart = 0; if (sign_x) { ps[istart++] = '-'; } ps[istart++] = '0'; ps[istart++] = 'E'; exponent_x -= 398; if (exponent_x < 0) { ps[istart++] = '-'; exponent_x = -exponent_x; } else ps[istart++] = '+'; if (exponent_x) { // get decimal digits in coefficient_x tempx.d = (float) exponent_x; bin_expon_cx = ((tempx.i >> 23) & 0xff) - 0x7f; digits_x = estimate_decimal_digits[bin_expon_cx]; if ((UINT64)exponent_x >= power10_table_128[digits_x].w[0]) digits_x++; j = istart + digits_x - 1; istart = j + 1; // 2^32/10 ER10 = 0x1999999a; while (exponent_x > 9) { D = (UINT64) exponent_x *ER10; D >>= 32; exponent_x = exponent_x - (D << 1) - (D << 3); ps[j--] = '0' + (char) exponent_x; exponent_x = D; } ps[j] = '0' + (char) exponent_x; } else { ps[istart++] = '0'; } ps[istart] = 0; return; } // convert expon, coeff to ASCII exponent_x -= DECIMAL_EXPONENT_BIAS; ER10 = 0x1999999a; istart = 0; if (sign_x) { ps[0] = '-'; istart = 1; } // if zero or non-canonical, set coefficient to '0' if ((coefficient_x > 9999999999999999ull) || // non-canonical ((coefficient_x == 0)) // significand is zero ) { ps[istart++] = '0'; } else { /* **************************************************** This takes a bid coefficient in C1.w[1],C1.w[0] and put the converted character sequence at location starting at &(str[k]). The function returns the number of MiDi returned. Note that the character sequence does not have leading zeros EXCEPT when the input is of zero value. It will then output 1 character '0' The algorithm essentailly tries first to get a sequence of Millenial Digits "MiDi" and then uses table lookup to get the character strings of these MiDis. **************************************************** */ /* Algorithm first decompose possibly 34 digits in hi and lo 18 digits. (The high can have at most 16 digits). It then uses macro that handle 18 digit portions. The first step is to get hi and lo such that 2^(64) C1.w[1] + C1.w[0] = hi * 10^18 + lo, 0 <= lo < 10^18. We use a table lookup method to obtain the hi and lo 18 digits. [C1.w[1],C1.w[0]] = c_8 2^(107) + c_7 2^(101) + ... + c_0 2^(59) + d where 0 <= d < 2^59 and each c_j has 6 bits. Because d fits in 18 digits, we set hi = 0, and lo = d to begin with. We then retrieve from a table, for j = 0, 1, ..., 8 that gives us A and B where c_j 2^(59+6j) = A * 10^18 + B. hi += A ; lo += B; After each accumulation into lo, we normalize immediately. So at the end, we have the decomposition as we need. */ Tmp = coefficient_x >> 59; LO_18Dig = (coefficient_x << 5) >> 5; HI_18Dig = 0; k_lcv = 0; while (Tmp) { midi_ind = (int) (Tmp & 0x000000000000003FLL); midi_ind <<= 1; Tmp >>= 6; HI_18Dig += mod10_18_tbl[k_lcv][midi_ind++]; LO_18Dig += mod10_18_tbl[k_lcv++][midi_ind]; __L0_Normalize_10to18 (HI_18Dig, LO_18Dig); } ptr = MiDi; __L1_Split_MiDi_6_Lead (LO_18Dig, ptr); len = ptr - MiDi; c_ptr_start = &(ps[istart]); c_ptr = c_ptr_start; /* now convert the MiDi into character strings */ __L0_MiDi2Str_Lead (MiDi[0], c_ptr); for (k_lcv = 1; k_lcv < len; k_lcv++) { __L0_MiDi2Str (MiDi[k_lcv], c_ptr); } istart = istart + (c_ptr - c_ptr_start); } ps[istart++] = 'E'; if (exponent_x < 0) { ps[istart++] = '-'; exponent_x = -exponent_x; } else ps[istart++] = '+'; if (exponent_x) { // get decimal digits in coefficient_x tempx.d = (float) exponent_x; bin_expon_cx = ((tempx.i >> 23) & 0xff) - 0x7f; digits_x = estimate_decimal_digits[bin_expon_cx]; if ((UINT64)exponent_x >= power10_table_128[digits_x].w[0]) digits_x++; j = istart + digits_x - 1; istart = j + 1; // 2^32/10 ER10 = 0x1999999a; while (exponent_x > 9) { D = (UINT64) exponent_x *ER10; D >>= 32; exponent_x = exponent_x - (D << 1) - (D << 3); ps[j--] = '0' + (char) exponent_x; exponent_x = D; } ps[j] = '0' + (char) exponent_x; } else { ps[istart++] = '0'; } ps[istart] = 0; return; } #if DECIMAL_CALL_BY_REFERENCE void bid64_from_string (UINT64 * pres, char *ps _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM _EXC_INFO_PARAM) { #else UINT64 bid64_from_string (char *ps _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM _EXC_INFO_PARAM) { #endif UINT64 sign_x, coefficient_x = 0, rounded = 0, res; int expon_x = 0, sgn_expon, ndigits, add_expon = 0, midpoint = 0, rounded_up = 0; int dec_expon_scale = 0, right_radix_leading_zeros = 0, rdx_pt_enc = 0; unsigned fpsc; char c; unsigned int save_fpsf; #if DECIMAL_CALL_BY_REFERENCE #if !DECIMAL_GLOBAL_ROUNDING _IDEC_round rnd_mode = *prnd_mode; #endif #endif save_fpsf = *pfpsf; // place holder only // eliminate leading whitespace while (((*ps == ' ') || (*ps == '\t')) && (*ps)) ps++; // get first non-whitespace character c = *ps; // detect special cases (INF or NaN) if (!c || (c != '.' && c != '-' && c != '+' && (c < '0' || c > '9'))) { // Infinity? if ((tolower_macro (ps[0]) == 'i' && tolower_macro (ps[1]) == 'n' && tolower_macro (ps[2]) == 'f') && (!ps[3] || (tolower_macro (ps[3]) == 'i' && tolower_macro (ps[4]) == 'n' && tolower_macro (ps[5]) == 'i' && tolower_macro (ps[6]) == 't' && tolower_macro (ps[7]) == 'y' && !ps[8]))) { res = 0x7800000000000000ull; BID_RETURN (res); } // return sNaN if (tolower_macro (ps[0]) == 's' && tolower_macro (ps[1]) == 'n' && tolower_macro (ps[2]) == 'a' && tolower_macro (ps[3]) == 'n') { // case insensitive check for snan res = 0x7e00000000000000ull; BID_RETURN (res); } else { // return qNaN res = 0x7c00000000000000ull; BID_RETURN (res); } } // detect +INF or -INF if ((tolower_macro (ps[1]) == 'i' && tolower_macro (ps[2]) == 'n' && tolower_macro (ps[3]) == 'f') && (!ps[4] || (tolower_macro (ps[4]) == 'i' && tolower_macro (ps[5]) == 'n' && tolower_macro (ps[6]) == 'i' && tolower_macro (ps[7]) == 't' && tolower_macro (ps[8]) == 'y' && !ps[9]))) { if (c == '+') res = 0x7800000000000000ull; else if (c == '-') res = 0xf800000000000000ull; else res = 0x7c00000000000000ull; BID_RETURN (res); } // if +sNaN, +SNaN, -sNaN, or -SNaN if (tolower_macro (ps[1]) == 's' && tolower_macro (ps[2]) == 'n' && tolower_macro (ps[3]) == 'a' && tolower_macro (ps[4]) == 'n') { if (c == '-') res = 0xfe00000000000000ull; else res = 0x7e00000000000000ull; BID_RETURN (res); } // determine sign if (c == '-') sign_x = 0x8000000000000000ull; else sign_x = 0; // get next character if leading +/- sign if (c == '-' || c == '+') { ps++; c = *ps; } // if c isn't a decimal point or a decimal digit, return NaN if (c != '.' && (c < '0' || c > '9')) { // return NaN res = 0x7c00000000000000ull | sign_x; BID_RETURN (res); } rdx_pt_enc = 0; // detect zero (and eliminate/ignore leading zeros) if (*(ps) == '0' || *(ps) == '.') { if (*(ps) == '.') { rdx_pt_enc = 1; ps++; } // if all numbers are zeros (with possibly 1 radix point, the number is zero // should catch cases such as: 000.0 while (*ps == '0') { ps++; // for numbers such as 0.0000000000000000000000000000000000001001, // we want to count the leading zeros if (rdx_pt_enc) { right_radix_leading_zeros++; } // if this character is a radix point, make sure we haven't already // encountered one if (*(ps) == '.') { if (rdx_pt_enc == 0) { rdx_pt_enc = 1; // if this is the first radix point, and the next character is NULL, // we have a zero if (!*(ps + 1)) { res = ((UINT64) (398 - right_radix_leading_zeros) << 53) | sign_x; BID_RETURN (res); } ps = ps + 1; } else { // if 2 radix points, return NaN res = 0x7c00000000000000ull | sign_x; BID_RETURN (res); } } else if (!*(ps)) { //pres->w[1] = 0x3040000000000000ull | sign_x; res = ((UINT64) (398 - right_radix_leading_zeros) << 53) | sign_x; BID_RETURN (res); } } } c = *ps; ndigits = 0; while ((c >= '0' && c <= '9') || c == '.') { if (c == '.') { if (rdx_pt_enc) { // return NaN res = 0x7c00000000000000ull | sign_x; BID_RETURN (res); } rdx_pt_enc = 1; ps++; c = *ps; continue; } dec_expon_scale += rdx_pt_enc; ndigits++; if (ndigits <= 16) { coefficient_x = (coefficient_x << 1) + (coefficient_x << 3); coefficient_x += (UINT64) (c - '0'); } else if (ndigits == 17) { // coefficient rounding switch(rnd_mode){ case ROUNDING_TO_NEAREST: midpoint = (c == '5' && !(coefficient_x & 1)) ? 1 : 0; // if coefficient is even and c is 5, prepare to round up if // subsequent digit is nonzero // if str[MAXDIG+1] > 5, we MUST round up // if str[MAXDIG+1] == 5 and coefficient is ODD, ROUND UP! if (c > '5' || (c == '5' && (coefficient_x & 1))) { coefficient_x++; rounded_up = 1; break; case ROUNDING_DOWN: if(sign_x) { coefficient_x++; rounded_up=1; } break; case ROUNDING_UP: if(!sign_x) { coefficient_x++; rounded_up=1; } break; case ROUNDING_TIES_AWAY: if(c>='5') { coefficient_x++; rounded_up=1; } break; } if (coefficient_x == 10000000000000000ull) { coefficient_x = 1000000000000000ull; add_expon = 1; } } if (c > '0') rounded = 1; add_expon += 1; } else { // ndigits > 17 add_expon++; if (midpoint && c > '0') { coefficient_x++; midpoint = 0; rounded_up = 1; } if (c > '0') rounded = 1; } ps++; c = *ps; } add_expon -= (dec_expon_scale + right_radix_leading_zeros); if (!c) { res = fast_get_BID64_check_OF (sign_x, add_expon + DECIMAL_EXPONENT_BIAS, coefficient_x, 0, &fpsc); BID_RETURN (res); } if (c != 'E' && c != 'e') { // return NaN res = 0x7c00000000000000ull | sign_x; BID_RETURN (res); } ps++; c = *ps; sgn_expon = (c == '-') ? 1 : 0; if (c == '-' || c == '+') { ps++; c = *ps; } if (!c || c < '0' || c > '9') { // return NaN res = 0x7c00000000000000ull | sign_x; BID_RETURN (res); } while (c >= '0' && c <= '9') { expon_x = (expon_x << 1) + (expon_x << 3); expon_x += (int) (c - '0'); ps++; c = *ps; } if (c) { // return NaN res = 0x7c00000000000000ull | sign_x; BID_RETURN (res); } if (sgn_expon) expon_x = -expon_x; expon_x += add_expon + DECIMAL_EXPONENT_BIAS; if (expon_x < 0) { if (rounded_up) coefficient_x--; rnd_mode = 0; res = get_BID64_UF (sign_x, expon_x, coefficient_x, rounded, rnd_mode, &fpsc); BID_RETURN (res); } res = get_BID64 (sign_x, expon_x, coefficient_x, rnd_mode, &fpsc); BID_RETURN (res); }