diff options
Diffstat (limited to 'sysdeps/powerpc/powerpc64/power4/fpu/mpa.c')
-rw-r--r-- | sysdeps/powerpc/powerpc64/power4/fpu/mpa.c | 112 |
1 files changed, 60 insertions, 52 deletions
diff --git a/sysdeps/powerpc/powerpc64/power4/fpu/mpa.c b/sysdeps/powerpc/powerpc64/power4/fpu/mpa.c index f30d2cb379..b22664772e 100644 --- a/sysdeps/powerpc/powerpc64/power4/fpu/mpa.c +++ b/sysdeps/powerpc/powerpc64/power4/fpu/mpa.c @@ -363,6 +363,7 @@ add_magnitudes (const mp_no *x, const mp_no *y, mp_no *z, int p) { long i, j, k; long p2 = p; + double zk; EZ = EX; @@ -370,45 +371,54 @@ add_magnitudes (const mp_no *x, const mp_no *y, mp_no *z, int p) j = p2 + EY - EX; k = p2 + 1; - if (j < 1) + if (__glibc_unlikely (j < 1)) { __cpy (x, z, p); return; } - else - Z[k] = ZERO; + + zk = ZERO; for (; j > 0; i--, j--) { - Z[k] += X[i] + Y[j]; - if (Z[k] >= RADIX) + zk += X[i] + Y[j]; + if (zk >= RADIX) { - Z[k] -= RADIX; - Z[--k] = ONE; + Z[k--] = zk - RADIX; + zk = ONE; } else - Z[--k] = ZERO; + { + Z[k--] = zk; + zk = ZERO; + } } for (; i > 0; i--) { - Z[k] += X[i]; - if (Z[k] >= RADIX) + zk += X[i]; + if (zk >= RADIX) { - Z[k] -= RADIX; - Z[--k] = ONE; + Z[k--] = zk - RADIX; + zk = ONE; } else - Z[--k] = ZERO; + { + Z[k--] = zk; + zk = ZERO; + } } - if (Z[1] == ZERO) + if (zk == ZERO) { for (i = 1; i <= p2; i++) Z[i] = Z[i + 1]; } else - EZ += ONE; + { + Z[1] = zk; + EZ += ONE; + } } /* Subtract the magnitudes of *X and *Y assuming that abs (*x) > abs (*y) > 0. @@ -420,65 +430,63 @@ sub_magnitudes (const mp_no *x, const mp_no *y, mp_no *z, int p) { long i, j, k; long p2 = p; + double zk; EZ = EX; + i = p2; + j = p2 + EY - EX; + k = p2; - if (EX == EY) + /* Y is too small compared to X, copy X over to the result. */ + if (__glibc_unlikely (j < 1)) { - i = j = k = p2; - Z[k] = Z[k + 1] = ZERO; + __cpy (x, z, p); + return; } - else + + /* The relevant least significant digit in Y is non-zero, so we factor it in + to enhance accuracy. */ + if (j < p2 && Y[j + 1] > ZERO) { - j = EX - EY; - if (j > p2) - { - __cpy (x, z, p); - return; - } - else - { - i = p2; - j = p2 + 1 - j; - k = p2; - if (Y[j] > ZERO) - { - Z[k + 1] = RADIX - Y[j--]; - Z[k] = MONE; - } - else - { - Z[k + 1] = ZERO; - Z[k] = ZERO; - j--; - } - } + Z[k + 1] = RADIX - Y[j + 1]; + zk = MONE; } + else + zk = Z[k + 1] = ZERO; + /* Subtract and borrow. */ for (; j > 0; i--, j--) { - Z[k] += (X[i] - Y[j]); - if (Z[k] < ZERO) + zk += (X[i] - Y[j]); + if (zk < ZERO) { - Z[k] += RADIX; - Z[--k] = MONE; + Z[k--] = zk + RADIX; + zk = MONE; } else - Z[--k] = ZERO; + { + Z[k--] = zk; + zk = ZERO; + } } + /* We're done with digits from Y, so it's just digits in X. */ for (; i > 0; i--) { - Z[k] += X[i]; - if (Z[k] < ZERO) + zk += X[i]; + if (zk < ZERO) { - Z[k] += RADIX; - Z[--k] = MONE; + Z[k--] = zk + RADIX; + zk = MONE; } else - Z[--k] = ZERO; + { + Z[k--] = zk; + zk = ZERO; + } } + /* Normalize. */ for (i = 1; Z[i] == ZERO; i++); EZ = EZ - i + 1; for (k = 1; i <= p2 + 1;) |