Merge tag 'ti-v2020.07-rc3' of https://gitlab.denx.de/u-boot/custodians/u-boot-ti

[oweals/u-boot.git] / lib / div64.c

diff --git a/lib/div64.c b/lib/div64.c
index 795ef0e1e4671ac7a68a189839d48028353c1c29..779d7521f69fdeab66d92e3dc736004eaefe306e 100644 (file)
--- a/lib/div64.c
+++ b/lib/div64.c
@@ -13,25 +13,38 @@
  *
  * Code generated for this function might be very inefficient
  * for some CPUs. __div64_32() can be overridden by linking arch-specific
- * assembly versions such as arch/powerpc/lib/div64.S and arch/sh/lib/div64.S.
+ * assembly versions such as arch/ppc/lib/div64.S and arch/sh/lib/div64.S
+ * or by defining a preprocessor macro in arch/include/asm/div64.h.
  */
 
-#include <div64.h>
-#include <linux/types.h>
+#include <linux/bitops.h>
+#include <linux/compat.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
 
-uint32_t __div64_32(uint64_t *n, uint32_t base)
+/* Not needed on 64bit architectures */
+#if BITS_PER_LONG == 32
+
+#ifndef __div64_32
+/*
+ * Don't instrument this function as it may be called from tracing code, since
+ * it needs to read the timer and this often requires calling do_div(), which
+ * calls this function.
+ */
+uint32_t __attribute__((weak, no_instrument_function)) __div64_32(u64 *n,
+                                                                 u32 base)
 {
-       uint64_t rem = *n;
-       uint64_t b = base;
-       uint64_t res, d = 1;
-       uint32_t high = rem >> 32;
+       u64 rem = *n;
+       u64 b = base;
+       u64 res, d = 1;
+       u32 high = rem >> 32;
 
        /* Reduce the thing a bit first */
        res = 0;
        if (high >= base) {
                high /= base;
-               res = (uint64_t) high << 32;
-               rem -= (uint64_t) (high*base) << 32;
+               res = (u64)high << 32;
+               rem -= (u64)(high * base) << 32;
        }
 
        while ((int64_t)b > 0 && b < rem) {
@@ -51,3 +64,129 @@ uint32_t __div64_32(uint64_t *n, uint32_t base)
        *n = res;
        return rem;
 }
+EXPORT_SYMBOL(__div64_32);
+#endif
+
+#ifndef div_s64_rem
+s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
+{
+       u64 quotient;
+
+       if (dividend < 0) {
+               quotient = div_u64_rem(-dividend, abs(divisor), (u32 *)remainder);
+               *remainder = -*remainder;
+               if (divisor > 0)
+                       quotient = -quotient;
+       } else {
+               quotient = div_u64_rem(dividend, abs(divisor), (u32 *)remainder);
+               if (divisor < 0)
+                       quotient = -quotient;
+       }
+       return quotient;
+}
+EXPORT_SYMBOL(div_s64_rem);
+#endif
+
+/**
+ * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder
+ * @dividend:  64bit dividend
+ * @divisor:   64bit divisor
+ * @remainder:  64bit remainder
+ *
+ * This implementation is a comparable to algorithm used by div64_u64.
+ * But this operation, which includes math for calculating the remainder,
+ * is kept distinct to avoid slowing down the div64_u64 operation on 32bit
+ * systems.
+ */
+#ifndef div64_u64_rem
+u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder)
+{
+       u32 high = divisor >> 32;
+       u64 quot;
+
+       if (high == 0) {
+               u32 rem32;
+               quot = div_u64_rem(dividend, divisor, &rem32);
+               *remainder = rem32;
+       } else {
+               int n = 1 + fls(high);
+               quot = div_u64(dividend >> n, divisor >> n);
+
+               if (quot != 0)
+                       quot--;
+
+               *remainder = dividend - quot * divisor;
+               if (*remainder >= divisor) {
+                       quot++;
+                       *remainder -= divisor;
+               }
+       }
+
+       return quot;
+}
+EXPORT_SYMBOL(div64_u64_rem);
+#endif
+
+/**
+ * div64_u64 - unsigned 64bit divide with 64bit divisor
+ * @dividend:  64bit dividend
+ * @divisor:   64bit divisor
+ *
+ * This implementation is a modified version of the algorithm proposed
+ * by the book 'Hacker's Delight'.  The original source and full proof
+ * can be found here and is available for use without restriction.
+ *
+ * 'http://www.hackersdelight.org/hdcodetxt/divDouble.c.txt'
+ */
+#ifndef div64_u64
+u64 div64_u64(u64 dividend, u64 divisor)
+{
+       u32 high = divisor >> 32;
+       u64 quot;
+
+       if (high == 0) {
+               quot = div_u64(dividend, divisor);
+       } else {
+               int n = 1 + fls(high);
+               quot = div_u64(dividend >> n, divisor >> n);
+
+               if (quot != 0)
+                       quot--;
+               if ((dividend - quot * divisor) >= divisor)
+                       quot++;
+       }
+
+       return quot;
+}
+EXPORT_SYMBOL(div64_u64);
+#endif
+
+/**
+ * div64_s64 - signed 64bit divide with 64bit divisor
+ * @dividend:  64bit dividend
+ * @divisor:   64bit divisor
+ */
+#ifndef div64_s64
+s64 div64_s64(s64 dividend, s64 divisor)
+{
+       s64 quot, t;
+
+       quot = div64_u64(abs(dividend), abs(divisor));
+       t = (dividend ^ divisor) >> 63;
+
+       return (quot ^ t) - t;
+}
+EXPORT_SYMBOL(div64_s64);
+#endif
+
+#endif /* BITS_PER_LONG == 32 */
+
+/*
+ * Iterative div/mod for use when dividend is not expected to be much
+ * bigger than divisor.
+ */
+u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
+{
+       return __iter_div_u64_rem(dividend, divisor, remainder);
+}
+EXPORT_SYMBOL(iter_div_u64_rem);