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author | Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2022-07-27 00:27:38 +0100 |
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committer | Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2022-11-14 12:00:58 +0000 |
commit | 2511d032f02e6426b0bd87d225b4b322a7154d15 (patch) | |
tree | 70946cd6a64e14f3ab6c79f4d8d21d88be2a621b | |
parent | 2953a3e187e054a4cfba4190a2037dc16b327372 (diff) | |
download | linux-2511d032f02e6426b0bd87d225b4b322a7154d15.tar.bz2 |
ARM: findbit: operate by words
Convert the implementations to operate on words rather than bytes
which makes bitmap searching faster.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
-rw-r--r-- | arch/arm/include/asm/assembler.h | 6 | ||||
-rw-r--r-- | arch/arm/lib/findbit.S | 78 |
2 files changed, 50 insertions, 34 deletions
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index 90fbe4a3f9c8..28e18f79c300 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -761,6 +761,12 @@ THUMB( orr \reg , \reg , #PSR_T_BIT ) .endif .endm + .if __LINUX_ARM_ARCH__ < 6 + .set .Lrev_l_uses_tmp, 1 + .else + .set .Lrev_l_uses_tmp, 0 + .endif + /* * bl_r - branch and link to register * diff --git a/arch/arm/lib/findbit.S b/arch/arm/lib/findbit.S index 8280f66d38a5..6ec584d16d46 100644 --- a/arch/arm/lib/findbit.S +++ b/arch/arm/lib/findbit.S @@ -14,32 +14,32 @@ #include <asm/assembler.h> .text +#ifdef __ARMEB__ +#define SWAB_ENDIAN le +#else +#define SWAB_ENDIAN be +#endif + .macro find_first, endian, set, name ENTRY(_find_first_\name\()bit_\endian) teq r1, #0 beq 3f mov r2, #0 -1: - .ifc \endian, be - eor r3, r2, #0x18 - ARM( ldrb r3, [r0, r3, lsr #3] ) - THUMB( lsr r3, #3 ) - THUMB( ldrb r3, [r0, r3] ) +1: ldr r3, [r0], #4 + .ifeq \set + mvns r3, r3 @ invert/test bits .else - ARM( ldrb r3, [r0, r2, lsr #3] ) - THUMB( lsr r3, r2, #3 ) - THUMB( ldrb r3, [r0, r3] ) + movs r3, r3 @ test bits .endif - .ifeq \set - eors r3, r3, #0xff @ invert bits + .ifc \endian, SWAB_ENDIAN + bne .L_found_swab .else - movs r3, r3 + bne .L_found @ found the bit? .endif - bne .L_found @ any now set - found zero bit - add r2, r2, #8 @ next bit pointer + add r2, r2, #32 @ next index 2: cmp r2, r1 @ any more? blo 1b -3: mov r0, r1 @ no free bits +3: mov r0, r1 @ no more bits ret lr ENDPROC(_find_first_\name\()bit_\endian) .endm @@ -48,24 +48,25 @@ ENDPROC(_find_first_\name\()bit_\endian) ENTRY(_find_next_\name\()bit_\endian) cmp r2, r1 bhs 3b - ands ip, r2, #7 - beq 1b @ If new byte, goto old routine - .ifc \endian, be - eor r3, r2, #0x18 - ARM( ldrb r3, [r0, r3, lsr #3] ) - THUMB( lsr r3, #3 ) - THUMB( ldrb r3, [r0, r3] ) - .else - ARM( ldrb r3, [r0, r2, lsr #3] ) - THUMB( lsr r3, r2, #3 ) - THUMB( ldrb r3, [r0, r3] ) + mov ip, r2, lsr #5 @ word index + add r0, r0, ip, lsl #2 + ands ip, r2, #31 @ bit position + beq 1b + ldr r3, [r0], #4 + .ifeq \set + mvn r3, r3 @ invert bits + .endif + .ifc \endian, SWAB_ENDIAN + rev_l r3, ip + .if .Lrev_l_uses_tmp + @ we need to recompute ip because rev_l will have overwritten + @ it. + and ip, r2, #31 @ bit position .endif - .ifeq \set - eor r3, r3, #0xff @ now looking for a 1 bit .endif movs r3, r3, lsr ip @ shift off unused bits bne .L_found - orr r2, r2, #7 @ if zero, then no bits here + orr r2, r2, #31 @ no zero bits add r2, r2, #1 @ align bit pointer b 2b @ loop for next bit ENDPROC(_find_next_\name\()bit_\endian) @@ -95,6 +96,8 @@ ENDPROC(_find_next_\name\()bit_\endian) /* * One or more bits in the LSB of r3 are assumed to be set. */ +.L_found_swab: + rev_l r3, ip .L_found: #if __LINUX_ARM_ARCH__ >= 7 rbit r3, r3 @ reverse bits @@ -107,13 +110,20 @@ ENDPROC(_find_next_\name\()bit_\endian) rsb r3, r3, #31 @ offset of first set bit add r0, r2, r3 @ add offset of first set bit #else - tst r3, #0x0f + mov ip, #~0 + tst r3, ip, lsr #16 @ test bits 0-15 + addeq r2, r2, #16 + moveq r3, r3, lsr #16 + tst r3, #0x00ff + addeq r2, r2, #8 + moveq r3, r3, lsr #8 + tst r3, #0x000f addeq r2, r2, #4 - movne r3, r3, lsl #4 - tst r3, #0x30 + moveq r3, r3, lsr #4 + tst r3, #0x0003 addeq r2, r2, #2 - movne r3, r3, lsl #2 - tst r3, #0x40 + moveq r3, r3, lsr #2 + tst r3, #0x0001 addeq r2, r2, #1 mov r0, r2 #endif |