[MIPS] Use MIPS R2 instructions for bitops.

Add R2 optimized variants of clear_bit, set_bit and test_and_clear_bit.
With gcc 4.1.1 this saves 1592 bytes on a defconfig (minus IPv6) kernel.
Turns out that R2 bitop instructions are no gain for the other bitop
functions.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/include/asm-mips/bitops.h b/include/asm-mips/bitops.h
index 06c08228a5256cbb3fa9320b102b09eb6e21774d..89436b96ad66ea9953309aa5ef8ba4560b03584b 100644 (file)
--- a/include/asm-mips/bitops.h
+++ b/include/asm-mips/bitops.h
@@ -3,7 +3,7 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (c) 1994 - 1997, 1999, 2000, 06  Ralf Baechle (ralf@linux-mips.org)
+ * Copyright (c) 1994 - 1997, 99, 2000, 06, 07  Ralf Baechle (ralf@linux-mips.org)
  * Copyright (c) 1999, 2000  Silicon Graphics, Inc.
  */
 #ifndef _ASM_BITOPS_H
@@ -24,11 +24,15 @@
 #define SZLONG_MASK 31UL
 #define __LL           "ll     "
 #define __SC           "sc     "
+#define __INS          "ins    "
+#define __EXT          "ext    "
 #elif (_MIPS_SZLONG == 64)
 #define SZLONG_LOG 6
 #define SZLONG_MASK 63UL
 #define __LL           "lld    "
 #define __SC           "scd    "
+#define __INS          "dins    "
+#define __EXT          "dext    "
 #endif
 
 /*
@@ -62,6 +66,19 @@ static inline void set_bit(unsigned long nr, volatile unsigned long *addr)
                "       .set    mips0                                   \n"
                : "=&r" (temp), "=m" (*m)
                : "ir" (1UL << (nr & SZLONG_MASK)), "m" (*m));
+#ifdef CONFIG_CPU_MIPSR2
+       } else if (__builtin_constant_p(nr)) {
+               __asm__ __volatile__(
+               "1:     " __LL "%0, %1                  # set_bit       \n"
+               "       " __INS "%0, %4, %2, 1                          \n"
+               "       " __SC "%0, %1                                  \n"
+               "       beqz    %0, 2f                                  \n"
+               "       .subsection 2                                   \n"
+               "2:     b       1b                                      \n"
+               "       .previous                                       \n"
+               : "=&r" (temp), "=m" (*m)
+               : "ir" (nr & SZLONG_MASK), "m" (*m), "r" (~0));
+#endif /* CONFIG_CPU_MIPSR2 */
        } else if (cpu_has_llsc) {
                __asm__ __volatile__(
                "       .set    mips3                                   \n"
@@ -113,6 +130,19 @@ static inline void clear_bit(unsigned long nr, volatile unsigned long *addr)
                "       .set    mips0                                   \n"
                : "=&r" (temp), "=m" (*m)
                : "ir" (~(1UL << (nr & SZLONG_MASK))), "m" (*m));
+#ifdef CONFIG_CPU_MIPSR2
+       } else if (__builtin_constant_p(nr)) {
+               __asm__ __volatile__(
+               "1:     " __LL "%0, %1                  # clear_bit     \n"
+               "       " __INS "%0, $0, %2, 1                          \n"
+               "       " __SC "%0, %1                                  \n"
+               "       beqz    %0, 2f                                  \n"
+               "       .subsection 2                                   \n"
+               "2:     b       1b                                      \n"
+               "       .previous                                       \n"
+               : "=&r" (temp), "=m" (*m)
+               : "ir" (nr & SZLONG_MASK), "m" (*m));
+#endif /* CONFIG_CPU_MIPSR2 */
        } else if (cpu_has_llsc) {
                __asm__ __volatile__(
                "       .set    mips3                                   \n"
@@ -291,6 +321,26 @@ static inline int test_and_clear_bit(unsigned long nr,
                : "memory");
 
                return res != 0;
+#ifdef CONFIG_CPU_MIPSR2
+       } else if (__builtin_constant_p(nr)) {
+               unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
+               unsigned long temp, res;
+
+               __asm__ __volatile__(
+               "1:     " __LL  "%0, %1         # test_and_clear_bit    \n"
+               "       " __EXT "%2, %0, %3, 1                          \n"
+               "       " __INS "%0, $0, %3, 1                          \n"
+               "       " __SC  "%0, %1                                 \n"
+               "       beqz    %0, 2f                                  \n"
+               "       .subsection 2                                   \n"
+               "2:     b       1b                                      \n"
+               "       .previous                                       \n"
+               : "=&r" (temp), "=m" (*m), "=&r" (res)
+               : "ri" (nr & SZLONG_MASK), "m" (*m)
+               : "memory");
+
+               return res;
+#endif
        } else if (cpu_has_llsc) {
                unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
                unsigned long temp, res;