Complete rewrite by Granlund and Drepper.
authorroland <roland>
Fri, 13 Oct 1995 23:47:59 +0000 (23:47 +0000)
committerroland <roland>
Fri, 13 Oct 1995 23:47:59 +0000 (23:47 +0000)
stdio/_itoa.c

index 19e732d..caa8179 100644 (file)
@@ -1,6 +1,8 @@
 /* Internal function for converting integers to ASCII.
 Copyright (C) 1994, 1995 Free Software Foundation, Inc.
 This file is part of the GNU C Library.
+Contributed by Torbjorn Granlund <tege@matematik.su.se>
+and Ulrich Drepper <drepper@gnu.ai.mit.edu>.
 
 The GNU C Library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Library General Public License as
@@ -17,13 +19,400 @@ License along with the GNU C Library; see the file COPYING.LIB.  If
 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
 Cambridge, MA 02139, USA.  */
 
+#include <gmp-mparam.h>
+#include "../stdlib/gmp.h"
+#include "../stdlib/gmp-impl.h"
+#include "../stdlib/longlong.h"
+
+#include "_itoa.h"
+
+
+/* Canonize environment.  For some architectures not all values might
+   be defined in the GMP header files.  */
+#ifndef UMUL_TIME
+# define UMUL_TIME 1
+#endif
+#ifndef UDIV_TIME
+# define UDIV_TIME 1
+#endif
+
+/* Control memory layout.  */
+#ifdef PACK
+# undef PACK
+# define PACK __attribute__ ((packed))
+#else
+# define PACK
+#endif
+
+
+/* Declare local types.  */
+struct base_table_t
+{
+#if (UDIV_TIME > 2 * UMUL_TIME)
+  mp_limb base_multiplier;
+#endif
+  char flag;
+  char post_shift;
+#if BITS_PER_MP_LIMB == 32
+  struct
+    {
+      char normalization_steps;
+      char ndigits;
+      mp_limb base PACK;
+#if UDIV_TIME > 2 * UMUL_TIME
+      mp_limb base_ninv PACK;
+#endif
+    } big;
+#endif
+};
+
+/* To reduce the memory needed we include some fields of the tables
+   only confitionally.  */
+#if BITS_PER_MP_LIMB == 32
+# if UDIV_TIME > 2 * UMUL_TIME
+#  define SEL1(X) X,
+#  define SEL2(X) ,X
+# else
+#  define SEL1(X)
+#  define SEL2(X)
+# endif
+#endif
+
+
+/* Local variables.  */
+static const struct base_table_t base_table[] =
+{
+#if BITS_PER_MP_LIMB == 64
+  /*  2 */ {0ul, 1, 1},
+  /*  3 */ {0xaaaaaaaaaaaaaaabul, 0, 1},
+  /*  4 */ {0ul, 1, 2},
+  /*  5 */ {0xcccccccccccccccdul, 0, 2},
+  /*  6 */ {0xaaaaaaaaaaaaaaabul, 0, 2},
+  /*  7 */ {0x2492492492492493ul, 1, 3},
+  /*  8 */ {0ul, 1, 3},
+  /*  9 */ {0xe38e38e38e38e38ful, 0, 3},
+  /* 10 */ {0xcccccccccccccccdul, 0, 3},
+  /* 11 */ {0x2e8ba2e8ba2e8ba3ul, 0, 1},
+  /* 12 */ {0xaaaaaaaaaaaaaaabul, 0, 3},
+  /* 13 */ {0x4ec4ec4ec4ec4ec5ul, 0, 2},
+  /* 14 */ {0x2492492492492493ul, 1, 4},
+  /* 15 */ {0x8888888888888889ul, 0, 3},
+  /* 16 */ {0ul, 1, 4},
+  /* 17 */ {0xf0f0f0f0f0f0f0f1ul, 0, 4},
+  /* 18 */ {0xe38e38e38e38e38ful, 0, 4},
+  /* 19 */ {0xd79435e50d79435ful, 0, 4},
+  /* 20 */ {0xcccccccccccccccdul, 0, 4},
+  /* 21 */ {0x8618618618618619ul, 1, 5},
+  /* 22 */ {0x2e8ba2e8ba2e8ba3ul, 0, 2},
+  /* 23 */ {0x642c8590b21642c9ul, 1, 5},
+  /* 24 */ {0xaaaaaaaaaaaaaaabul, 0, 4},
+  /* 25 */ {0x47ae147ae147ae15ul, 1, 5},
+  /* 26 */ {0x4ec4ec4ec4ec4ec5ul, 0, 3},
+  /* 27 */ {0x97b425ed097b425ful, 0, 4},
+  /* 28 */ {0x2492492492492493ul, 1, 5},
+  /* 29 */ {0x1a7b9611a7b9611bul, 1, 5},
+  /* 30 */ {0x8888888888888889ul, 0, 4},
+  /* 31 */ {0x0842108421084211ul, 1, 5},
+  /* 32 */ {0ul, 1, 5},
+  /* 33 */ {0x0f83e0f83e0f83e1ul, 0, 1},
+  /* 34 */ {0xf0f0f0f0f0f0f0f1ul, 0, 5},
+  /* 35 */ {0xea0ea0ea0ea0ea0ful, 0, 5},
+  /* 36 */ {0xe38e38e38e38e38ful, 0, 5}
+#endif
+#if BITS_PER_MP_LIMB == 32
+  /*  2 */ {SEL1(0ul) 1, 1, {0, 31, 0x80000000ul SEL2(0xfffffffful)}},
+  /*  3 */ {SEL1(0xaaaaaaabul) 0, 1, {0, 20, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
+  /*  4 */ {SEL1(0ul) 1, 2, {1, 15, 0x40000000ul SEL2(0xfffffffful)}},
+  /*  5 */ {SEL1(0xcccccccdul) 0, 2, {1, 13, 0x48c27395ul SEL2(0xc25c2684ul)}},
+  /*  6 */ {SEL1(0xaaaaaaabul) 0, 2, {0, 12, 0x81bf1000ul SEL2(0xf91bd1b6ul)}},
+  /*  7 */ {SEL1(0x24924925ul) 1, 3, {1, 11, 0x75db9c97ul SEL2(0x1607a2cbul)}},
+  /*  8 */ {SEL1(0ul) 1, 3, {1, 10, 0x40000000ul SEL2(0xfffffffful)}},
+  /*  9 */ {SEL1(0x38e38e39ul) 0, 1, {0, 10, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
+  /* 10 */ {SEL1(0xcccccccdul) 0, 3, {2, 9, 0x3b9aca00ul SEL2(0x12e0be82ul)}},
+  /* 11 */ {SEL1(0xba2e8ba3ul) 0, 3, {0, 9, 0x8c8b6d2bul SEL2(0xd24cde04ul)}},
+  /* 12 */ {SEL1(0xaaaaaaabul) 0, 3, {3, 8, 0x19a10000ul SEL2(0x3fa39ab5ul)}},
+  /* 13 */ {SEL1(0x4ec4ec4ful) 0, 2, {2, 8, 0x309f1021ul SEL2(0x50f8ac5ful)}},
+  /* 14 */ {SEL1(0x24924925ul) 1, 4, {1, 8, 0x57f6c100ul SEL2(0x74843b1eul)}},
+  /* 15 */ {SEL1(0x88888889ul) 0, 3, {0, 8, 0x98c29b81ul SEL2(0xad0326c2ul)}},
+  /* 16 */ {SEL1(0ul) 1, 4, {3, 7, 0x10000000ul SEL2(0xfffffffful)}},
+  /* 17 */ {SEL1(0xf0f0f0f1ul) 0, 4, {3, 7, 0x18754571ul SEL2(0x4ef0b6bdul)}},
+  /* 18 */ {SEL1(0x38e38e39ul) 0, 2, {2, 7, 0x247dbc80ul SEL2(0xc0fc48a1ul)}},
+  /* 19 */ {SEL1(0xaf286bcbul) 1, 5, {2, 7, 0x3547667bul SEL2(0x33838942ul)}},
+  /* 20 */ {SEL1(0xcccccccdul) 0, 4, {1, 7, 0x4c4b4000ul SEL2(0xad7f29abul)}},
+  /* 21 */ {SEL1(0x86186187ul) 1, 5, {1, 7, 0x6b5a6e1dul SEL2(0x313c3d15ul)}},
+  /* 22 */ {SEL1(0xba2e8ba3ul) 0, 4, {0, 7, 0x94ace180ul SEL2(0xb8cca9e0ul)}},
+  /* 23 */ {SEL1(0xb21642c9ul) 0, 4, {0, 7, 0xcaf18367ul SEL2(0x42ed6de9ul)}},
+  /* 24 */ {SEL1(0xaaaaaaabul) 0, 4, {4, 6, 0x0b640000ul SEL2(0x67980e0bul)}},
+  /* 25 */ {SEL1(0x51eb851ful) 0, 3, {4, 6, 0x0e8d4a51ul SEL2(0x19799812ul)}},
+  /* 26 */ {SEL1(0x4ec4ec4ful) 0, 3, {3, 6, 0x1269ae40ul SEL2(0xbce85396ul)}},
+  /* 27 */ {SEL1(0x2f684bdbul) 1, 5, {3, 6, 0x17179149ul SEL2(0x62c103a9ul)}},
+  /* 28 */ {SEL1(0x24924925ul) 1, 5, {3, 6, 0x1cb91000ul SEL2(0x1d353d43ul)}},
+  /* 29 */ {SEL1(0x8d3dcb09ul) 0, 4, {2, 6, 0x23744899ul SEL2(0xce1deceaul)}},
+  /* 30 */ {SEL1(0x88888889ul) 0, 4, {2, 6, 0x2b73a840ul SEL2(0x790fc511ul)}},
+  /* 31 */ {SEL1(0x08421085ul) 1, 5, {2, 6, 0x34e63b41ul SEL2(0x35b865a0ul)}},
+  /* 32 */ {SEL1(0ul) 1, 5, {1, 6, 0x40000000ul SEL2(0xfffffffful)}},
+  /* 33 */ {SEL1(0x3e0f83e1ul) 0, 3, {1, 6, 0x4cfa3cc1ul SEL2(0xa9aed1b3ul)}},
+  /* 34 */ {SEL1(0xf0f0f0f1ul) 0, 5, {1, 6, 0x5c13d840ul SEL2(0x63dfc229ul)}},
+  /* 35 */ {SEL1(0xd41d41d5ul) 1, 6, {1, 6, 0x6d91b519ul SEL2(0x2b0fee30ul)}},
+  /* 36 */ {SEL1(0x38e38e39ul) 0, 3, {0, 6, 0x81bf1000ul SEL2(0xf91bd1b6ul)}}
+#endif
+};
+
 /* Lower-case digits.  */
-const char _itoa_lower_digits[] = "0123456789abcdefghijklmnopqrstuvwxyz";
+static const char _itoa_lower_digits[]
+       = "0123456789abcdefghijklmnopqrstuvwxyz";
 /* Upper-case digits.  */
-const char _itoa_upper_digits[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+static const char _itoa_upper_digits[]
+       = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 
-/* Cause _itoa.h to define _itoa as a real function instead of an
-   `extern inline'.  */
-#define _EXTERN_INLINE /* empty */
 
-#include "_itoa.h"
+char *
+_itoa (value, buflim, base, upper_case)
+     unsigned long long int value;
+     char *buflim;
+     unsigned int base;
+     int upper_case;
+{
+  const char *digits = upper_case ? _itoa_upper_digits : _itoa_lower_digits;
+  char *bp = buflim;
+  const struct base_table_t *brec = &base_table[base - 2];
+
+  switch (base)
+    {
+#define RUN_2N(BITS)                                                     \
+      do                                                                 \
+        {                                                                \
+         /* `unsigned long long int' always has 64 bits.  */             \
+         mp_limb work_hi = value >> (64 - BITS_PER_MP_LIMB);             \
+                                                                         \
+         if (BITS_PER_MP_LIMB == 32)                                     \
+           if (work_hi != 0)                                             \
+             {                                                           \
+               mp_limb work_lo;                                          \
+               int cnt;                                                  \
+                                                                         \
+               work_lo = value & 0xfffffffful;                           \
+               for (cnt = BITS_PER_MP_LIMB / BITS; cnt > 0; --cnt)       \
+                 {                                                       \
+                   *--bp = digits[work_lo & ((1ul << BITS) - 1)];        \
+                   work_lo >>= BITS;                                     \
+                 }                                                       \
+               if (BITS_PER_MP_LIMB % BITS != 0)                         \
+                 {                                                       \
+                   work_lo |= ((work_hi                                  \
+                                & ((1 << BITS - BITS_PER_MP_LIMB % BITS) \
+                                   - 1))                                 \
+                               << BITS_PER_MP_LIMB % BITS);              \
+                   *--bp = digits[work_lo];                              \
+                   work_hi >>= BITS - BITS_PER_MP_LIMB % BITS;           \
+                 }                                                       \
+             }                                                           \
+           else                                                          \
+             work_hi = value & 0xfffffffful;                             \
+         do                                                              \
+           {                                                             \
+             *--bp = digits[work_hi & ((1 << BITS) - 1)];                \
+             work_hi >>= BITS;                                           \
+           }                                                             \
+         while (work_hi != 0);                                           \
+       }                                                                 \
+      while (0)
+    case 8:
+      RUN_2N (3);
+      break;
+
+    case 16:
+      RUN_2N (4);
+      break;
+
+    default:
+      {
+#if BITS_PER_MP_LIMB == 64
+       mp_limb base_multiplier = brec->base_multiplier;
+       if (brec->flag)
+         while (value != 0)
+           {
+             mp_limb quo, rem, x, dummy;
+
+             umul_ppmm (x, dummy, value, base_multiplier);
+             quo = (x + ((value - x) >> 1)) >> (brec->post_shift - 1);
+             rem = value - quo * base;
+             *--bp = digits[rem];
+             value = quo;
+           }
+       else
+         while (value != 0)
+           {
+             mp_limb quo, rem, x, dummy;
+
+             umul_ppmm (x, dummy, value, base_multiplier);
+             quo = x >> brec->post_shift;
+             rem = value - quo * base;
+             *--bp = digits[rem];
+             value = quo;
+           }
+#endif
+#if BITS_PER_MP_LIMB == 32
+       mp_limb t[3];
+       int n;
+
+       /* First convert x0 to 1-3 words in base s->big.base.
+          Optimize for frequent cases of 32 bit numbers.  */
+       if ((mp_limb) (value >> 32) >= 1)
+         {
+           int big_normalization_steps = brec->big.normalization_steps;
+           mp_limb big_base_norm = brec->big.base << big_normalization_steps;
+
+           if ((mp_limb) (value >> 32) >= brec->big.base)
+             {
+               mp_limb x1hi, x1lo, r;
+               /* If you want to optimize this, take advantage of
+                  that the quotient in the first udiv_qrnnd will
+                  always be very small.  It might be faster just to
+                  subtract in a tight loop.  */
+
+#if UDIV_TIME > 2 * UMUL_TIME
+               mp_limb x, xh, xl;
+
+               if (big_normalization_steps == 0)
+                 xh = 0;
+               else
+                 xh = (mp_limb) (value >> 64 - big_normalization_steps);
+               xl = (mp_limb) (value >> 32 - big_normalization_steps);
+               udiv_qrnnd_preinv (x1hi, r, xh, xl, big_base_norm,
+                                  brec->big.base_ninv);
+
+               xl = ((mp_limb) value) << big_normalization_steps;
+               udiv_qrnnd_preinv (x1lo, x, r, xl, big_base_norm,
+                                  big_normalization_steps);
+               t[2] = x >> big_normalization_steps;
+
+               if (big_normalization_steps == 0)
+                 xh = x1hi;
+               else
+                 xh = ((x1hi << big_normalization_steps)
+                       | (x1lo >> 32 - big_normalization_steps));
+               xl = x1lo << big_normalization_steps;
+               udiv_qrnnd_preinv (t[0], x, xh, xl, big_base_norm,
+                                  big_normalization_steps);
+               t[1] = x >> big_normalization_steps;
+#elif UDIV_NEEDS_NORMALIZATION
+               mp_limb x, xh, xl;
+
+               if (big_normalization_steps == 0)
+                 xh = 0;
+               else
+                 xh = (mp_limb) (value >> 64 - big_normalization_steps);
+               xl = (mp_limb) (value >> 32 - big_normalization_steps);
+               udiv_qrnnd (x1hi, r, xh, xl, big_base_norm);
+
+               xl = ((mp_limb) value) << big_normalization_steps;
+               udiv_qrnnd (x1lo, x, r, xl, big_base_norm);
+               t[2] = x >> big_normalization_steps;
+
+               if (big_normalization_steps == 0)
+                 xh = x1hi;
+               else
+                 xh = ((x1hi << big_normalization_steps)
+                       | (x1lo >> 32 - big_normalization_steps));
+               xl = x1lo << big_normalization_steps;
+               udiv_qrnnd (t[0], x, xh, xl, big_base_norm);
+               t[1] = x >> big_normalization_steps;
+#else
+               udiv_qrnnd (x1hi, r, 0, (mp_limb) (value >> 32),
+                           brec->big.base);
+               udiv_qrnnd (x1lo, t[2], r, (mp_limb) value, brec->big.base);
+               udiv_qrnnd (t[0], t[1], x1hi, x1lo, brec->big.base);
+#endif
+               n = 3;
+             }
+           else
+             {
+#if (UDIV_TIME > 2 * UMUL_TIME)
+               mp_limb x;
+
+               value <<= brec->big.normalization_steps;
+               udiv_qrnnd_preinv (t[0], x, (mp_limb) (value >> 32),
+                                  (mp_limb) value, big_base_norm,
+                                  brec->big.base_ninv);
+               t[1] = x >> brec->big.normalization_steps;
+#elif UDIV_NEEDS_NORMALIZATION
+               mp_limb x;
+
+               value <<= big_normalization_steps;
+               udiv_qrnnd (t[0], x, (mp_limb) (value >> 32),
+                           (mp_limb) value, big_base_norm);
+               t[1] = x >> big_normalization_steps;
+#else
+               udiv_qrnnd (t[0], t[1], (mp_limb) (value >> 32),
+                           (mp_limb) value, brec->big.base);
+#endif
+               n = 2;
+             }
+         }
+       else
+         {
+           t[0] = value;
+           n = 1;
+         }
+
+       /* Convert the 1-3 words in t[], word by word, to ASCII.  */
+       do
+         {
+           mp_limb ti = t[--n];
+           int ndig_for_this_limb = 0;
+
+#if UDIV_TIME > 2 * UMUL_TIME
+           mp_limb base_multiplier = brec->base_multiplier;
+           if (brec->flag)
+             while (ti != 0)
+               {
+                 mp_limb quo, rem, x, dummy;
+
+                 umul_ppmm (x, dummy, ti, base_multiplier);
+                 quo = (x + ((ti - x) >> 1)) >> (brec->post_shift - 1);
+                 rem = ti - quo * base;
+                 *--bp = digits[rem];
+                 ti = quo;
+                 ++ndig_for_this_limb;
+               }
+           else
+             while (ti != 0)
+               {
+                 mp_limb quo, rem, x, dummy;
+
+                 umul_ppmm (x, dummy, ti, base_multiplier);
+                 quo = x >> brec->post_shift;
+                 rem = ti - quo * base;
+                 *--bp = digits[rem];
+                 ti = quo;
+                 ++ndig_for_this_limb;
+               }
+#else
+           while (ti != 0)
+             {
+               mp_limb quo, rem;
+
+               quo = ti / base;
+               rem = ti % base;
+               *--bp = digits[rem];
+               ti = quo;
+               ++ndig_for_this_limb;
+             }
+#endif
+           /* If this wasn't the most significant word, pad with zeros.  */
+           if (n != 0)
+             while (ndig_for_this_limb < brec->big.ndigits)
+               {
+                 *--bp = '0';
+                 ++ndig_for_this_limb;
+               }
+         }
+       while (n != 0);
+#endif
+      }
+      break;
+    }
+
+  return bp;
+}