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-rw-r--r--lib/udivmodti4.c221
1 files changed, 118 insertions, 103 deletions
diff --git a/lib/udivmodti4.c b/lib/udivmodti4.c
index 79cf6f2fc..12fa49cda 100644
--- a/lib/udivmodti4.c
+++ b/lib/udivmodti4.c
@@ -1,24 +1,26 @@
-//===-- udivmodti4.c - Implement __udivmodti4 -----------------------------===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file implements __udivmodti4 for the compiler_rt library.
-//
-//===----------------------------------------------------------------------===//
+/* ===-- udivmodti4.c - Implement __udivmodti4 -----------------------------===
+ *
+ * The LLVM Compiler Infrastructure
+ *
+ * This file is distributed under the University of Illinois Open Source
+ * License. See LICENSE.TXT for details.
+ *
+ * ===----------------------------------------------------------------------===
+ *
+ * This file implements __udivmodti4 for the compiler_rt library.
+ *
+ * ===----------------------------------------------------------------------===
+ */
#if __x86_64
#include "int_lib.h"
-// Effects: if rem != 0, *rem = a % b
-// Returns: a / b
+/* Effects: if rem != 0, *rem = a % b
+ * Returns: a / b
+ */
-// Translated from Figure 3-40 of The PowerPC Compiler Writer's Guide
+/* Translated from Figure 3-40 of The PowerPC Compiler Writer's Guide */
tu_int
__udivmodti4(tu_int a, tu_int b, tu_int* rem)
@@ -32,43 +34,47 @@ __udivmodti4(tu_int a, tu_int b, tu_int* rem)
utwords q;
utwords r;
unsigned sr;
- // special cases, X is unknown, K != 0
+ /* special cases, X is unknown, K != 0 */
if (n.high == 0)
{
if (d.high == 0)
{
- // 0 X
- // ---
- // 0 X
+ /* 0 X
+ * ---
+ * 0 X
+ */
if (rem)
*rem = n.low % d.low;
return n.low / d.low;
}
- // 0 X
- // ---
- // K X
+ /* 0 X
+ * ---
+ * K X
+ */
if (rem)
*rem = n.low;
return 0;
}
- // n.high != 0
+ /* n.high != 0 */
if (d.low == 0)
{
if (d.high == 0)
{
- // K X
- // ---
- // 0 0
+ /* K X
+ * ---
+ * 0 0
+ */
if (rem)
*rem = n.high % d.low;
return n.high / d.low;
}
- // d.high != 0
+ /* d.high != 0 */
if (n.low == 0)
{
- // K 0
- // ---
- // K 0
+ /* K 0
+ * ---
+ * K 0
+ */
if (rem)
{
r.high = n.high % d.high;
@@ -77,10 +83,11 @@ __udivmodti4(tu_int a, tu_int b, tu_int* rem)
}
return n.high / d.high;
}
- // K K
- // ---
- // K 0
- if ((d.high & (d.high - 1)) == 0) // if d is a power of 2
+ /* K K
+ * ---
+ * K 0
+ */
+ if ((d.high & (d.high - 1)) == 0) /* if d is a power of 2 */
{
if (rem)
{
@@ -90,11 +97,12 @@ __udivmodti4(tu_int a, tu_int b, tu_int* rem)
}
return n.high >> __builtin_ctzll(d.high);
}
- // K K
- // ---
- // K 0
+ /* K K
+ * ---
+ * K 0
+ */
sr = __builtin_clzll(d.high) - __builtin_clzll(n.high);
- // 0 <= sr <= n_udword_bits - 2 or sr large
+ /* 0 <= sr <= n_udword_bits - 2 or sr large */
if (sr > n_udword_bits - 2)
{
if (rem)
@@ -102,22 +110,23 @@ __udivmodti4(tu_int a, tu_int b, tu_int* rem)
return 0;
}
++sr;
- // 1 <= sr <= n_udword_bits - 1
- // q.all = n.all << (n_utword_bits - sr);
+ /* 1 <= sr <= n_udword_bits - 1 */
+ /* q.all = n.all << (n_utword_bits - sr); */
q.low = 0;
q.high = n.low << (n_udword_bits - sr);
- // r.all = n.all >> sr;
+ /* r.all = n.all >> sr; */
r.high = n.high >> sr;
r.low = (n.high << (n_udword_bits - sr)) | (n.low >> sr);
}
- else // d.low != 0
+ else /* d.low != 0 */
{
if (d.high == 0)
{
- // K X
- // ---
- // 0 K
- if ((d.low & (d.low - 1)) == 0) // if d is a power of 2
+ /* K X
+ * ---
+ * 0 K
+ */
+ if ((d.low & (d.low - 1)) == 0) /* if d is a power of 2 */
{
if (rem)
*rem = n.low & (d.low - 1);
@@ -128,36 +137,38 @@ __udivmodti4(tu_int a, tu_int b, tu_int* rem)
q.low = (n.high << (n_udword_bits - sr)) | (n.low >> sr);
return q.all;
}
- // K X
- // ---
- // 0 K
+ /* K X
+ * ---
+ * 0 K
+ */
sr = 1 + n_udword_bits + __builtin_clzll(d.low)
- __builtin_clzll(n.high);
- // 2 <= sr <= n_utword_bits - 1
- // q.all = n.all << (n_utword_bits - sr);
- // r.all = n.all >> sr;
- // if (sr == n_udword_bits)
- // {
- // q.low = 0;
- // q.high = n.low;
- // r.high = 0;
- // r.low = n.high;
- // }
- // else if (sr < n_udword_bits) // 2 <= sr <= n_udword_bits - 1
- // {
- // q.low = 0;
- // q.high = n.low << (n_udword_bits - sr);
- // r.high = n.high >> sr;
- // r.low = (n.high << (n_udword_bits - sr)) | (n.low >> sr);
- // }
- // else // n_udword_bits + 1 <= sr <= n_utword_bits - 1
- // {
- // q.low = n.low << (n_utword_bits - sr);
- // q.high = (n.high << (n_utword_bits - sr)) |
- // (n.low >> (sr - n_udword_bits));
- // r.high = 0;
- // r.low = n.high >> (sr - n_udword_bits);
- // }
+ /* 2 <= sr <= n_utword_bits - 1
+ * q.all = n.all << (n_utword_bits - sr);
+ * r.all = n.all >> sr;
+ * if (sr == n_udword_bits)
+ * {
+ * q.low = 0;
+ * q.high = n.low;
+ * r.high = 0;
+ * r.low = n.high;
+ * }
+ * else if (sr < n_udword_bits) // 2 <= sr <= n_udword_bits - 1
+ * {
+ * q.low = 0;
+ * q.high = n.low << (n_udword_bits - sr);
+ * r.high = n.high >> sr;
+ * r.low = (n.high << (n_udword_bits - sr)) | (n.low >> sr);
+ * }
+ * else // n_udword_bits + 1 <= sr <= n_utword_bits - 1
+ * {
+ * q.low = n.low << (n_utword_bits - sr);
+ * q.high = (n.high << (n_utword_bits - sr)) |
+ * (n.low >> (sr - n_udword_bits));
+ * r.high = 0;
+ * r.low = n.high >> (sr - n_udword_bits);
+ * }
+ */
q.low = (n.low << (n_utword_bits - sr)) &
((di_int)(int)(n_udword_bits - sr) >> (n_udword_bits-1));
q.high = ((n.low << ( n_udword_bits - sr)) &
@@ -175,11 +186,12 @@ __udivmodti4(tu_int a, tu_int b, tu_int* rem)
}
else
{
- // K X
- // ---
- // K K
+ /* K X
+ * ---
+ * K K
+ */
sr = __builtin_clzll(d.high) - __builtin_clzll(n.high);
- // 0 <= sr <= n_udword_bits - 1 or sr large
+ /*0 <= sr <= n_udword_bits - 1 or sr large */
if (sr > n_udword_bits - 1)
{
if (rem)
@@ -187,21 +199,22 @@ __udivmodti4(tu_int a, tu_int b, tu_int* rem)
return 0;
}
++sr;
- // 1 <= sr <= n_udword_bits
- // q.all = n.all << (n_utword_bits - sr);
+ /* 1 <= sr <= n_udword_bits */
+ /* q.all = n.all << (n_utword_bits - sr); */
q.low = 0;
q.high = n.low << (n_udword_bits - sr);
- // r.all = n.all >> sr;
- // if (sr < n_udword_bits)
- // {
- // r.high = n.high >> sr;
- // r.low = (n.high << (n_udword_bits - sr)) | (n.low >> sr);
- // }
- // else
- // {
- // r.high = 0;
- // r.low = n.high;
- // }
+ /* r.all = n.all >> sr;
+ * if (sr < n_udword_bits)
+ * {
+ * r.high = n.high >> sr;
+ * r.low = (n.high << (n_udword_bits - sr)) | (n.low >> sr);
+ * }
+ * else
+ * {
+ * r.high = 0;
+ * r.low = n.high;
+ * }
+ */
r.high = (n.high >> sr) &
((di_int)(int)(sr - n_udword_bits) >> (n_udword_bits-1));
r.low = (n.high << (n_udword_bits - sr)) |
@@ -209,25 +222,27 @@ __udivmodti4(tu_int a, tu_int b, tu_int* rem)
((di_int)(int)(sr - n_udword_bits) >> (n_udword_bits-1)));
}
}
- // Not a special case
- // q and r are initialized with:
- // q.all = n.all << (n_utword_bits - sr);
- // r.all = n.all >> sr;
- // 1 <= sr <= n_utword_bits - 1
+ /* Not a special case
+ * q and r are initialized with:
+ * q.all = n.all << (n_utword_bits - sr);
+ * r.all = n.all >> sr;
+ * 1 <= sr <= n_utword_bits - 1
+ */
su_int carry = 0;
for (; sr > 0; --sr)
{
- // r:q = ((r:q) << 1) | carry
+ /* r:q = ((r:q) << 1) | carry */
r.high = (r.high << 1) | (r.low >> (n_udword_bits - 1));
r.low = (r.low << 1) | (q.high >> (n_udword_bits - 1));
q.high = (q.high << 1) | (q.low >> (n_udword_bits - 1));
q.low = (q.low << 1) | carry;
- // carry = 0;
- // if (r.all >= d.all)
- // {
- // r.all -= d.all;
- // carry = 1;
- // }
+ /* carry = 0;
+ * if (r.all >= d.all)
+ * {
+ * r.all -= d.all;
+ * carry = 1;
+ * }
+ */
const ti_int s = (ti_int)(d.all - r.all - 1) >> (n_utword_bits - 1);
carry = s & 1;
r.all -= d.all & s;
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-19 09:03:19 +0000