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Subject[PATCH v2 21/36] MIPS: bitops: Allow immediates in test_and_{set,clear,change}_bit
Date
The logical operations or & xor used in the test_and_set_bit_lock(),
test_and_clear_bit() & test_and_change_bit() functions currently force
the value 1<<bit to be placed in a register. If the bit is compile-time
constant & fits within the immediate field of an or/xor instruction (ie.
16 bits) then we can make use of the ori/xori instruction variants &
avoid the use of an extra register. Add the extra "i" constraints in
order to allow use of these immediate encodings.

Signed-off-by: Paul Burton <paul.burton@mips.com>
---

Changes in v2: None

arch/mips/include/asm/bitops.h | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/mips/include/asm/bitops.h b/arch/mips/include/asm/bitops.h
index ea35a2e87b6d..7314ba5a3683 100644
--- a/arch/mips/include/asm/bitops.h
+++ b/arch/mips/include/asm/bitops.h
@@ -261,7 +261,7 @@ static inline int test_and_set_bit_lock(unsigned long nr,
" and %2, %0, %3 \n"
" .set pop \n"
: "=&r" (temp), "+m" (*m), "=&r" (res)
- : "r" (1UL << bit)
+ : "ir" (1UL << bit)
: __LLSC_CLOBBER);
} else {
loongson_llsc_mb();
@@ -274,7 +274,7 @@ static inline int test_and_set_bit_lock(unsigned long nr,
" " __SC "%2, %1 \n"
" .set pop \n"
: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (*m), "=&r" (res)
- : "r" (1UL << bit)
+ : "ir" (1UL << bit)
: __LLSC_CLOBBER);
} while (unlikely(!res));

@@ -332,7 +332,7 @@ static inline int test_and_clear_bit(unsigned long nr,
" and %2, %0, %3 \n"
" .set pop \n"
: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (*m), "=&r" (res)
- : "r" (1UL << bit)
+ : "ir" (1UL << bit)
: __LLSC_CLOBBER);
} else if ((MIPS_ISA_REV >= 2) && __builtin_constant_p(nr)) {
loongson_llsc_mb();
@@ -358,7 +358,7 @@ static inline int test_and_clear_bit(unsigned long nr,
" " __SC "%2, %1 \n"
" .set pop \n"
: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (*m), "=&r" (res)
- : "r" (1UL << bit)
+ : "ir" (1UL << bit)
: __LLSC_CLOBBER);
} while (unlikely(!res));

@@ -400,7 +400,7 @@ static inline int test_and_change_bit(unsigned long nr,
" and %2, %0, %3 \n"
" .set pop \n"
: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (*m), "=&r" (res)
- : "r" (1UL << bit)
+ : "ir" (1UL << bit)
: __LLSC_CLOBBER);
} else {
loongson_llsc_mb();
@@ -413,7 +413,7 @@ static inline int test_and_change_bit(unsigned long nr,
" " __SC "\t%2, %1 \n"
" .set pop \n"
: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (*m), "=&r" (res)
- : "r" (1UL << bit)
+ : "ir" (1UL << bit)
: __LLSC_CLOBBER);
} while (unlikely(!res));

--
2.23.0
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