From 5e0b8d508ed51004bd836384293be00950ee62c9 Mon Sep 17 00:00:00 2001
From: Pasha <pasha@member.fsf.org>
Date: Tue, 20 Feb 2024 18:49:50 +0000
Subject: init gnumach copy

---
 linux/src/include/asm-i386/bitops.h | 201 ++++++++++++++++++++++++++++++++++++
 1 file changed, 201 insertions(+)
 create mode 100644 linux/src/include/asm-i386/bitops.h

(limited to 'linux/src/include/asm-i386/bitops.h')

diff --git a/linux/src/include/asm-i386/bitops.h b/linux/src/include/asm-i386/bitops.h
new file mode 100644
index 0000000..e2a4c14
--- /dev/null
+++ b/linux/src/include/asm-i386/bitops.h
@@ -0,0 +1,201 @@
+#ifndef _I386_BITOPS_H
+#define _I386_BITOPS_H
+
+/*
+ * Copyright 1992, Linus Torvalds.
+ */
+
+/*
+ * These have to be done with inline assembly: that way the bit-setting
+ * is guaranteed to be atomic. All bit operations return 0 if the bit
+ * was cleared before the operation and != 0 if it was not.
+ *
+ * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
+ */
+
+#ifdef __SMP__
+#define LOCK_PREFIX "lock ; "
+#define SMPVOL volatile
+#else
+#define LOCK_PREFIX ""
+#define SMPVOL
+#endif
+
+/*
+ * Some hacks to defeat gcc over-optimizations..
+ */
+struct __dummy { unsigned long a[100]; };
+#define ADDR (*(struct __dummy *) addr)
+#define CONST_ADDR (*(const struct __dummy *) addr)
+
+static __inline__ int set_bit(int nr, SMPVOL void * addr)
+{
+	int oldbit;
+
+	__asm__ __volatile__(LOCK_PREFIX
+		"btsl %2,%1\n\tsbbl %0,%0"
+		:"=r" (oldbit),"=m" (ADDR)
+		:"ir" (nr));
+	return oldbit;
+}
+
+static __inline__ int clear_bit(int nr, SMPVOL void * addr)
+{
+	int oldbit;
+
+	__asm__ __volatile__(LOCK_PREFIX
+		"btrl %2,%1\n\tsbbl %0,%0"
+		:"=r" (oldbit),"=m" (ADDR)
+		:"ir" (nr));
+	return oldbit;
+}
+
+static __inline__ int change_bit(int nr, SMPVOL void * addr)
+{
+	int oldbit;
+
+	__asm__ __volatile__(LOCK_PREFIX
+		"btcl %2,%1\n\tsbbl %0,%0"
+		:"=r" (oldbit),"=m" (ADDR)
+		:"ir" (nr));
+	return oldbit;
+}
+
+static __inline__ int test_and_set_bit(int nr, volatile void * addr)
+{
+	int oldbit;
+
+	__asm__ __volatile__( LOCK_PREFIX
+		"btsl %2,%1\n\tsbbl %0,%0"
+		:"=r" (oldbit),"=m" (ADDR)
+		:"Ir" (nr));
+	return oldbit;
+}
+
+static __inline__ int test_and_clear_bit(int nr, volatile void * addr)
+{
+	int oldbit;
+
+	__asm__ __volatile__( LOCK_PREFIX
+		"btrl %2,%1\n\tsbbl %0,%0"
+		:"=r" (oldbit),"=m" (ADDR)
+		:"Ir" (nr));
+	return oldbit;
+}
+
+static __inline__ int test_and_change_bit(int nr, volatile void * addr)
+{
+	int oldbit;
+
+	__asm__ __volatile__( LOCK_PREFIX
+		"btcl %2,%1\n\tsbbl %0,%0"
+		:"=r" (oldbit),"=m" (ADDR)
+		:"Ir" (nr));
+	return oldbit;
+}
+
+
+/*
+ * This routine doesn't need to be atomic.
+ */
+static __inline__ int test_bit(int nr, const SMPVOL void * addr)
+{
+	return ((1UL << (nr & 31)) & (((const unsigned int *) addr)[nr >> 5])) != 0;
+}
+
+/*
+ * Find-bit routines..
+ */
+static __inline__ int find_first_zero_bit(void * addr, unsigned size)
+{
+	int d0, d1, d2;
+	int res;
+
+	if (!size)
+		return 0;
+	__asm__("cld\n\t"
+		"movl $-1,%%eax\n\t"
+		"xorl %%edx,%%edx\n\t"
+		"repe; scasl\n\t"
+		"je 1f\n\t"
+		"xorl -4(%%edi),%%eax\n\t"
+		"subl $4,%%edi\n\t"
+		"bsfl %%eax,%%edx\n"
+		"1:\tsubl %%ebx,%%edi\n\t"
+		"shll $3,%%edi\n\t"
+		"addl %%edi,%%edx"
+		:"=d" (res), "=&c" (d0), "=&D" (d1), "=&a" (d2)
+		:"1" ((size + 31) >> 5), "2" (addr), "b" (addr));
+	return res;
+}
+
+static __inline__ int find_next_zero_bit (void * addr, int size, int offset)
+{
+	unsigned long * p = ((unsigned long *) addr) + (offset >> 5);
+	int set = 0, bit = offset & 31, res;
+	
+	if (bit) {
+		/*
+		 * Look for zero in first byte
+		 */
+		__asm__("bsfl %1,%0\n\t"
+			"jne 1f\n\t"
+			"movl $32, %0\n"
+			"1:"
+			: "=r" (set)
+			: "r" (~(*p >> bit)));
+		if (set < (32 - bit))
+			return set + offset;
+		set = 32 - bit;
+		p++;
+	}
+	/*
+	 * No zero yet, search remaining full bytes for a zero
+	 */
+	res = find_first_zero_bit (p, size - 32 * (p - (unsigned long *) addr));
+	return (offset + set + res);
+}
+
+/*
+ * ffz = Find First Zero in word. Undefined if no zero exists,
+ * so code should check against ~0UL first..
+ */
+static __inline__ unsigned long ffz(unsigned long word)
+{
+	__asm__("bsfl %1,%0"
+		:"=r" (word)
+		:"r" (~word));
+	return word;
+}
+
+#ifdef __KERNEL__
+
+/*
+ * ffs: find first bit set. This is defined the same way as
+ * the libc and compiler builtin ffs routines, therefore
+ * differs in spirit from the above ffz (man ffs).
+ */
+
+static __inline__ int ffs(int x)
+{
+	int r;
+
+	__asm__("bsfl %1,%0\n\t"
+		"jnz 1f\n\t"
+		"movl $-1,%0\n"
+		"1:" : "=r" (r) : "g" (x));
+	return r+1;
+}
+
+/*
+ * hweightN: returns the hamming weight (i.e. the number
+ * of bits set) of a N-bit word
+ */
+
+#define hweight32(x) generic_hweight32(x)
+#define hweight16(x) generic_hweight16(x)
+#define hweight8(x) generic_hweight8(x)
+
+#endif /* __KERNEL__ */
+
+#endif /* _I386_BITOPS_H */
-- 
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