[src/rec_sqrt.c] fixed for 8-bit limb

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@13172 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 15 insertions, 6 deletions

diff --git a/src/rec_sqrt.c b/src/rec_sqrt.c
index 0e5a435ee..a6b106a3e 100644
--- a/src/rec_sqrt.c
+++ b/src/rec_sqrt.c
@@ -179,7 +179,7 @@ mpfr_mpn_rec_sqrt (mpfr_limb_ptr x, mpfr_prec_t p,
   if (p == 11) /* should happen only from recursive calls */
     {
       unsigned long i, ab, ac;
-      mp_limb_t t;
+      int t;
 
       /* take the 12+as most significant bits of A */
 #if GMP_NUMB_BITS >= 16
@@ -196,8 +196,16 @@ mpfr_mpn_rec_sqrt (mpfr_limb_ptr x, mpfr_prec_t p,
       /* if one wants faithful rounding for p=11, replace #if 0 by #if 1 */
       ab = i >> 4;
       ac = (ab & 0x3F0) | (i & 0x0F);
-      t = (mp_limb_t) T1[ab - 0x80] + (mp_limb_t) T2[ac - 0x80];
-      x[0] = t << (GMP_NUMB_BITS - p);
+      t = (int) T1[ab - 0x80] + (int) T2[ac - 0x80];
+      if (GMP_NUMB_BITS >= 16) /* x has only one limb */
+        x[0] = t << (GMP_NUMB_BITS - p);
+      else
+        {
+          MPFR_ASSERTD(GMP_NUMB_BITS == 8);
+          /* 1024 <= t <= 2047 */
+          x[1] = t >> 3; /* 128 <= x[1] <= 255 */
+          x[0] = MPFR_LIMB_LSHIFT(t, 5);
+        }
     }
   else /* p >= 12 */
     {
@@ -235,7 +243,7 @@ mpfr_mpn_rec_sqrt (mpfr_limb_ptr x, mpfr_prec_t p,
 
       /* we need h+1+as bits of a */
       ahn = LIMB_SIZE(h + 1 + as); /* number of high limbs of A
-                                      needed for the recursive call*/
+                                      needed for the recursive call */
       if (MPFR_UNLIKELY(ahn > an))
         ahn = an;
       mpfr_mpn_rec_sqrt (x + ln, h, a + an - ahn, ahn * GMP_NUMB_BITS, as);
@@ -383,9 +391,10 @@ mpfr_mpn_rec_sqrt (mpfr_limb_ptr x, mpfr_prec_t p,
          thus we round u to nearest at bit pl-1 of u[0] */
       if (pl > 0)
         {
-          cu = mpn_add_1 (u, u, un, u[0] & (MPFR_LIMB_ONE << (pl - 1)));
+          cu = mpn_add_1 (u, u, un,
+                          u[0] & MPFR_LIMB_LSHIFT(MPFR_LIMB_ONE, pl - 1));
           /* mask bits 0..pl-1 of u[0] */
-          u[0] &= ~MPFR_LIMB_MASK(pl);
+          u[0] &= MPFR_LIMB(~MPFR_LIMB_MASK(pl));
         }
       else /* round bit is in u[-1] */
         cu = mpn_add_1 (u, u, un, u[-1] >> (GMP_NUMB_BITS - 1));