[PATCH] riscv: Avoid code duplication with generic bitops implementation
Xiao Wang
xiao.w.wang at intel.com
Sun Nov 12 01:44:21 PST 2023
There's code duplication between the fallback implementation for bitops
__ffs/__fls/ffs/fls API and the generic C implementation in
include/asm-generic/bitops/. To avoid this duplication, this patch renames
the generic C implementation by adding a "generic_" prefix to them, then we
can use these generic APIs as fallback.
Suggested-by: Geert Uytterhoeven <geert at linux-m68k.org>
Signed-off-by: Xiao Wang <xiao.w.wang at intel.com>
---
arch/riscv/include/asm/bitops.h | 138 +++++------------------------
include/asm-generic/bitops/__ffs.h | 8 +-
include/asm-generic/bitops/__fls.h | 8 +-
include/asm-generic/bitops/ffs.h | 8 +-
include/asm-generic/bitops/fls.h | 8 +-
5 files changed, 48 insertions(+), 122 deletions(-)
diff --git a/arch/riscv/include/asm/bitops.h b/arch/riscv/include/asm/bitops.h
index f7c167646460..23f7c122b151 100644
--- a/arch/riscv/include/asm/bitops.h
+++ b/arch/riscv/include/asm/bitops.h
@@ -22,6 +22,16 @@
#include <asm-generic/bitops/fls.h>
#else
+#define __HAVE_ARCH___FFS
+#define __HAVE_ARCH___FLS
+#define __HAVE_ARCH_FFS
+#define __HAVE_ARCH_FLS
+
+#include <asm-generic/bitops/__ffs.h>
+#include <asm-generic/bitops/__fls.h>
+#include <asm-generic/bitops/ffs.h>
+#include <asm-generic/bitops/fls.h>
+
#include <asm/alternative-macros.h>
#include <asm/hwcap.h>
@@ -37,8 +47,6 @@
static __always_inline unsigned long variable__ffs(unsigned long word)
{
- int num;
-
asm_volatile_goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
@@ -52,32 +60,7 @@ static __always_inline unsigned long variable__ffs(unsigned long word)
return word;
legacy:
- num = 0;
-#if BITS_PER_LONG == 64
- if ((word & 0xffffffff) == 0) {
- num += 32;
- word >>= 32;
- }
-#endif
- if ((word & 0xffff) == 0) {
- num += 16;
- word >>= 16;
- }
- if ((word & 0xff) == 0) {
- num += 8;
- word >>= 8;
- }
- if ((word & 0xf) == 0) {
- num += 4;
- word >>= 4;
- }
- if ((word & 0x3) == 0) {
- num += 2;
- word >>= 2;
- }
- if ((word & 0x1) == 0)
- num += 1;
- return num;
+ return generic___ffs(word);
}
/**
@@ -93,8 +76,6 @@ static __always_inline unsigned long variable__ffs(unsigned long word)
static __always_inline unsigned long variable__fls(unsigned long word)
{
- int num;
-
asm_volatile_goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
@@ -108,32 +89,7 @@ static __always_inline unsigned long variable__fls(unsigned long word)
return BITS_PER_LONG - 1 - word;
legacy:
- num = BITS_PER_LONG - 1;
-#if BITS_PER_LONG == 64
- if (!(word & (~0ul << 32))) {
- num -= 32;
- word <<= 32;
- }
-#endif
- if (!(word & (~0ul << (BITS_PER_LONG - 16)))) {
- num -= 16;
- word <<= 16;
- }
- if (!(word & (~0ul << (BITS_PER_LONG - 8)))) {
- num -= 8;
- word <<= 8;
- }
- if (!(word & (~0ul << (BITS_PER_LONG - 4)))) {
- num -= 4;
- word <<= 4;
- }
- if (!(word & (~0ul << (BITS_PER_LONG - 2)))) {
- num -= 2;
- word <<= 2;
- }
- if (!(word & (~0ul << (BITS_PER_LONG - 1))))
- num -= 1;
- return num;
+ return generic___fls(word);
}
/**
@@ -149,46 +105,23 @@ static __always_inline unsigned long variable__fls(unsigned long word)
static __always_inline int variable_ffs(int x)
{
- int r;
-
- if (!x)
- return 0;
-
asm_volatile_goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
+ if (!x)
+ return 0;
+
asm volatile (".option push\n"
".option arch,+zbb\n"
CTZW "%0, %1\n"
".option pop\n"
- : "=r" (r) : "r" (x) :);
+ : "=r" (x) : "r" (x) :);
- return r + 1;
+ return x + 1;
legacy:
- r = 1;
- if (!(x & 0xffff)) {
- x >>= 16;
- r += 16;
- }
- if (!(x & 0xff)) {
- x >>= 8;
- r += 8;
- }
- if (!(x & 0xf)) {
- x >>= 4;
- r += 4;
- }
- if (!(x & 3)) {
- x >>= 2;
- r += 2;
- }
- if (!(x & 1)) {
- x >>= 1;
- r += 1;
- }
- return r;
+ return generic_ffs(x);
}
/**
@@ -204,46 +137,23 @@ static __always_inline int variable_ffs(int x)
static __always_inline int variable_fls(unsigned int x)
{
- int r;
-
- if (!x)
- return 0;
-
asm_volatile_goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
+ if (!x)
+ return 0;
+
asm volatile (".option push\n"
".option arch,+zbb\n"
CLZW "%0, %1\n"
".option pop\n"
- : "=r" (r) : "r" (x) :);
+ : "=r" (x) : "r" (x) :);
- return 32 - r;
+ return 32 - x;
legacy:
- r = 32;
- if (!(x & 0xffff0000u)) {
- x <<= 16;
- r -= 16;
- }
- if (!(x & 0xff000000u)) {
- x <<= 8;
- r -= 8;
- }
- if (!(x & 0xf0000000u)) {
- x <<= 4;
- r -= 4;
- }
- if (!(x & 0xc0000000u)) {
- x <<= 2;
- r -= 2;
- }
- if (!(x & 0x80000000u)) {
- x <<= 1;
- r -= 1;
- }
- return r;
+ return generic_fls(x);
}
/**
diff --git a/include/asm-generic/bitops/__ffs.h b/include/asm-generic/bitops/__ffs.h
index 39e56e1c7203..446fea6dda78 100644
--- a/include/asm-generic/bitops/__ffs.h
+++ b/include/asm-generic/bitops/__ffs.h
@@ -5,12 +5,12 @@
#include <asm/types.h>
/**
- * __ffs - find first bit in word.
+ * generic___ffs - find first bit in word.
* @word: The word to search
*
* Undefined if no bit exists, so code should check against 0 first.
*/
-static __always_inline unsigned long __ffs(unsigned long word)
+static __always_inline unsigned long generic___ffs(unsigned long word)
{
int num = 0;
@@ -41,4 +41,8 @@ static __always_inline unsigned long __ffs(unsigned long word)
return num;
}
+#ifndef __HAVE_ARCH___FFS
+#define __ffs(word) generic___ffs(word)
+#endif
+
#endif /* _ASM_GENERIC_BITOPS___FFS_H_ */
diff --git a/include/asm-generic/bitops/__fls.h b/include/asm-generic/bitops/__fls.h
index 03f721a8a2b1..54ccccf96e21 100644
--- a/include/asm-generic/bitops/__fls.h
+++ b/include/asm-generic/bitops/__fls.h
@@ -5,12 +5,12 @@
#include <asm/types.h>
/**
- * __fls - find last (most-significant) set bit in a long word
+ * generic___fls - find last (most-significant) set bit in a long word
* @word: the word to search
*
* Undefined if no set bit exists, so code should check against 0 first.
*/
-static __always_inline unsigned long __fls(unsigned long word)
+static __always_inline unsigned long generic___fls(unsigned long word)
{
int num = BITS_PER_LONG - 1;
@@ -41,4 +41,8 @@ static __always_inline unsigned long __fls(unsigned long word)
return num;
}
+#ifndef __HAVE_ARCH___FLS
+#define __fls(word) generic___fls(word)
+#endif
+
#endif /* _ASM_GENERIC_BITOPS___FLS_H_ */
diff --git a/include/asm-generic/bitops/ffs.h b/include/asm-generic/bitops/ffs.h
index 323fd5d6ae26..4c43f242daeb 100644
--- a/include/asm-generic/bitops/ffs.h
+++ b/include/asm-generic/bitops/ffs.h
@@ -3,14 +3,14 @@
#define _ASM_GENERIC_BITOPS_FFS_H_
/**
- * ffs - find first bit set
+ * generic_ffs - find first bit set
* @x: the word to search
*
* This is defined the same way as
* the libc and compiler builtin ffs routines, therefore
* differs in spirit from ffz (man ffs).
*/
-static inline int ffs(int x)
+static inline int generic_ffs(int x)
{
int r = 1;
@@ -39,4 +39,8 @@ static inline int ffs(int x)
return r;
}
+#ifndef __HAVE_ARCH_FFS
+#define ffs(x) generic_ffs(x)
+#endif
+
#endif /* _ASM_GENERIC_BITOPS_FFS_H_ */
diff --git a/include/asm-generic/bitops/fls.h b/include/asm-generic/bitops/fls.h
index b168bb10e1be..26f3ce1dd6e4 100644
--- a/include/asm-generic/bitops/fls.h
+++ b/include/asm-generic/bitops/fls.h
@@ -3,14 +3,14 @@
#define _ASM_GENERIC_BITOPS_FLS_H_
/**
- * fls - find last (most-significant) bit set
+ * generic_fls - find last (most-significant) bit set
* @x: the word to search
*
* This is defined the same way as ffs.
* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
*/
-static __always_inline int fls(unsigned int x)
+static __always_inline int generic_fls(unsigned int x)
{
int r = 32;
@@ -39,4 +39,8 @@ static __always_inline int fls(unsigned int x)
return r;
}
+#ifndef __HAVE_ARCH_FLS
+#define fls(x) generic_fls(x)
+#endif
+
#endif /* _ASM_GENERIC_BITOPS_FLS_H_ */
--
2.25.1
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