第一次提交

devices/include/bits.h

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+/*
+ * Copyright (c) 2008 Travis Geiselbrecht
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#ifndef DEV_BITS_H
+#define DEV_BITS_H
+
+#include <types.h>
+#include <compiler.h>
+#include <armv7-r/atomic.h>
+
+#define BIT(x, bit) ((x) & (1UL << (bit)))
+#define BIT_SHIFT(x, bit) (((x) >> (bit)) & 1)
+#define BITS(x, high, low) ((x) & (((1UL<<((high)+1))-1) & ~((1UL<<(low))-1)))
+#define BITS_SHIFT(x, high, low) (((x) >> (low)) & ((1UL<<((high)-(low)+1))-1))
+#define BIT_SET(x, bit) (((x) & (1UL << (bit))) ? 1 : 0)
+
+#define BITMAP_BITS_PER_WORD (sizeof(unsigned long) * 8)
+#define BITMAP_NUM_WORDS(x) (((x) + BITMAP_BITS_PER_WORD - 1) / BITMAP_BITS_PER_WORD)
+#define BITMAP_WORD(x) ((x) / BITMAP_BITS_PER_WORD)
+#define BITMAP_BIT_IN_WORD(x) ((x) & (BITMAP_BITS_PER_WORD - 1))
+
+#define BITMAP_BITS_PER_INT (sizeof(unsigned int) * 8)
+#define BITMAP_BIT_IN_INT(x) ((x) & (BITMAP_BITS_PER_INT - 1))
+#define BITMAP_INT(x) ((x) / BITMAP_BITS_PER_INT)
+
+#define BIT_MASK(x) (((x) >= sizeof(unsigned long) * 8) ? (0UL-1) : ((1UL << (x)) - 1))
+
+static inline int bitmap_set(unsigned long *bitmap, int bit)
+{
+    unsigned long mask = 1UL << BITMAP_BIT_IN_INT(bit);
+    return arch_atomic_or(&((int *)bitmap)[BITMAP_INT(bit)], mask) & mask ? 1 : 0;
+}
+
+static inline int bitmap_clear(unsigned long *bitmap, int bit)
+{
+    unsigned long mask = 1UL << BITMAP_BIT_IN_INT(bit);
+
+    return arch_atomic_and(&((int *)bitmap)[BITMAP_INT(bit)], ~mask) & mask ? 1:0;
+}
+
+static inline int bitmap_test(unsigned long *bitmap, int bit)
+{
+    return BIT_SET(bitmap[BITMAP_WORD(bit)], BITMAP_BIT_IN_WORD(bit));
+}
+
+/* find first zero bit starting from LSB */
+static inline unsigned long _ffz(unsigned long x)
+{
+    /* only for gcc, TODO */
+    return __builtin_ffsl(~x) - 1;
+}
+
+static inline int bitmap_ffz(unsigned long *bitmap, int numbits)
+{
+    uint32_t i;
+    int bit;
+
+    for (i = 0; i < BITMAP_NUM_WORDS(numbits); i++) {
+        if (bitmap[i] == ~0UL)
+            continue;
+        bit = i * BITMAP_BITS_PER_WORD + _ffz(bitmap[i]);
+        if (bit < numbits)
+            return bit;
+        return -1;
+    }
+    return -1;
+}
+
+#endif