[PATCH] MIPS: import optimized string functions from Linux
Aleksey Kuleshov
rndfax at yandex.ru
Tue Nov 24 08:38:22 PST 2015
10x performance gain according to simple test on QEMU malta:
barebox:/ time memcpy 0xa0000000 0xa0001000 0x100000
Signed-off-by: Aleksey Kuleshov <rndfax at yandex.ru>
---
arch/mips/Kconfig | 7 ++
arch/mips/include/asm/string.h | 9 +-
arch/mips/lib/Makefile | 3 +
arch/mips/lib/memcpy.S | 276 +++++++++++++++++++++++++++++++++++++++++
arch/mips/lib/memset.S | 146 ++++++++++++++++++++++
5 files changed, 440 insertions(+), 1 deletion(-)
create mode 100644 arch/mips/lib/memcpy.S
create mode 100644 arch/mips/lib/memset.S
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index a2d443f..7deb825 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -331,6 +331,13 @@ config NMON_HELP
Say yes here to get the nmon commands message on
every nmon start.
+config MIPS_OPTIMZED_STRING_FUNCTIONS
+ bool "use assembler optimized string functions"
+ help
+ Say yes here to use assembler optimized memcpy / memset functions.
+ These functions work much faster than the normal versions but
+ increase your binary size.
+
endmenu
source common/Kconfig
diff --git a/arch/mips/include/asm/string.h b/arch/mips/include/asm/string.h
index 3a32d18..5a12b38 100644
--- a/arch/mips/include/asm/string.h
+++ b/arch/mips/include/asm/string.h
@@ -22,6 +22,13 @@
#ifndef __ASM_MIPS_STRING_H
#define __ASM_MIPS_STRING_H
-/* nothing special yet */
+#ifdef CONFIG_MIPS_OPTIMZED_STRING_FUNCTIONS
+
+#define __HAVE_ARCH_MEMCPY
+extern void *memcpy(void *, const void *, __kernel_size_t);
+#define __HAVE_ARCH_MEMSET
+extern void *memset(void *, int, __kernel_size_t);
+
+#endif
#endif
diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile
index 0145f35..7970f25 100644
--- a/arch/mips/lib/Makefile
+++ b/arch/mips/lib/Makefile
@@ -7,6 +7,9 @@ obj-y += cpu-probe.o
obj-y += traps.o
obj-y += genex.o
+obj-$(CONFIG_MIPS_OPTIMZED_STRING_FUNCTIONS) += memcpy.o
+obj-$(CONFIG_MIPS_OPTIMZED_STRING_FUNCTIONS) += memset.o
+
obj-$(CONFIG_CPU_MIPS32) += c-r4k.o
obj-$(CONFIG_CPU_MIPS64) += c-r4k.o
diff --git a/arch/mips/lib/memcpy.S b/arch/mips/lib/memcpy.S
new file mode 100644
index 0000000..a5af0c9
--- /dev/null
+++ b/arch/mips/lib/memcpy.S
@@ -0,0 +1,276 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1998, 99, 2000, 01, 2002 Ralf Baechle (ralf at gnu.org)
+ * Copyright (C) 1999, 2000, 01, 2002 Silicon Graphics, Inc.
+ * Copyright (C) 2002 Broadcom, Inc.
+ * memcpy/copy_user author: Mark Vandevoorde
+ * Copyright (C) 2007 Maciej W. Rozycki
+ * Copyright (C) 2014 Imagination Technologies Ltd.
+ *
+ * Kernel-mode memcpy function without exceptions for _some_ MIPS CPUs
+ * by Aleksey Kuleshov (rndfax at yandex.ru), 2015
+ *
+ */
+
+#include <asm/asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/regdef.h>
+
+#define dst a0
+#define src a1
+#define len a2
+
+#define LOADK lw /* No exception */
+#define LOAD(reg, addr) lw reg, addr
+#define LOADL(reg, addr) lwl reg, addr
+#define LOADR(reg, addr) lwr reg, addr
+#define STOREL(reg, addr) swl reg, addr
+#define STORER(reg, addr) swr reg, addr
+#define STORE(reg, addr) sw reg, addr
+#define ADD addu
+#define SUB subu
+#define SRL srl
+#define SLL sll
+#define SRA sra
+#define SLLV sllv
+#define SRLV srlv
+#define NBYTES 4
+#define LOG_NBYTES 2
+
+#define LOADB(reg, addr) lb reg, addr
+#define STOREB(reg, addr) sb reg, addr
+
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+#define LDFIRST LOADR
+#define LDREST LOADL
+#define STFIRST STORER
+#define STREST STOREL
+#define SHIFT_DISCARD SLLV
+#else
+#define LDFIRST LOADL
+#define LDREST LOADR
+#define STFIRST STOREL
+#define STREST STORER
+#define SHIFT_DISCARD SRLV
+#endif
+
+#define FIRST(unit) ((unit)*NBYTES)
+#define REST(unit) (FIRST(unit)+NBYTES-1)
+#define UNIT(unit) FIRST(unit)
+
+#define ADDRMASK (NBYTES-1)
+
+ .text
+ .align 5
+ .set noreorder
+LEAF(memcpy) /* a0=dst a1=src a2=len */
+ move v0, dst /* return value */
+
+ /*
+ * Note: dst & src may be unaligned, len may be 0
+ * Temps
+ */
+#define rem t8
+
+ /*
+ * The "issue break"s below are very approximate.
+ * Issue delays for dcache fills will perturb the schedule, as will
+ * load queue full replay traps, etc.
+ *
+ * If len < NBYTES use byte operations.
+ */
+ sltu t2, len, NBYTES
+ and t1, dst, ADDRMASK
+ bnez t2, .Lcopy_bytes_checklen
+ and t0, src, ADDRMASK
+ bnez t1, .Ldst_unaligned
+ nop
+ bnez t0, .Lsrc_unaligned_dst_aligned
+ /*
+ * use delay slot for fall-through
+ * src and dst are aligned; need to compute rem
+ */
+.Lboth_aligned:
+ SRL t0, len, LOG_NBYTES+3 # +3 for 8 units/iter
+ beqz t0, .Lcleanup_both_aligned # len < 8*NBYTES
+ and rem, len, (8*NBYTES-1) # rem = len % (8*NBYTES)
+ .align 4
+1:
+ LOAD(t0, UNIT(0)(src))
+ LOAD(t1, UNIT(1)(src))
+ LOAD(t2, UNIT(2)(src))
+ LOAD(t3, UNIT(3)(src))
+ SUB len, len, 8*NBYTES
+ LOAD(t4, UNIT(4)(src))
+ LOAD(t7, UNIT(5)(src))
+ STORE(t0, UNIT(0)(dst))
+ STORE(t1, UNIT(1)(dst))
+ LOAD(t0, UNIT(6)(src))
+ LOAD(t1, UNIT(7)(src))
+ ADD src, src, 8*NBYTES
+ ADD dst, dst, 8*NBYTES
+ STORE(t2, UNIT(-6)(dst))
+ STORE(t3, UNIT(-5)(dst))
+ STORE(t4, UNIT(-4)(dst))
+ STORE(t7, UNIT(-3)(dst))
+ STORE(t0, UNIT(-2)(dst))
+ STORE(t1, UNIT(-1)(dst))
+ bne len, rem, 1b
+ nop
+
+ /*
+ * len == rem == the number of bytes left to copy < 8*NBYTES
+ */
+.Lcleanup_both_aligned:
+ beqz len, .Ldone
+ sltu t0, len, 4*NBYTES
+ bnez t0, .Lless_than_4units
+ and rem, len, (NBYTES-1) # rem = len % NBYTES
+ /*
+ * len >= 4*NBYTES
+ */
+ LOAD( t0, UNIT(0)(src))
+ LOAD( t1, UNIT(1)(src))
+ LOAD( t2, UNIT(2)(src))
+ LOAD( t3, UNIT(3)(src))
+ SUB len, len, 4*NBYTES
+ ADD src, src, 4*NBYTES
+ STORE(t0, UNIT(0)(dst))
+ STORE(t1, UNIT(1)(dst))
+ STORE(t2, UNIT(2)(dst))
+ STORE(t3, UNIT(3)(dst))
+ .set reorder /* DADDI_WAR */
+ ADD dst, dst, 4*NBYTES
+ beqz len, .Ldone
+ .set noreorder
+.Lless_than_4units:
+ /*
+ * rem = len % NBYTES
+ */
+ beq rem, len, .Lcopy_bytes
+ nop
+1:
+ LOAD(t0, 0(src))
+ ADD src, src, NBYTES
+ SUB len, len, NBYTES
+ STORE(t0, 0(dst))
+ .set reorder /* DADDI_WAR */
+ ADD dst, dst, NBYTES
+ bne rem, len, 1b
+ .set noreorder
+
+ /*
+ * src and dst are aligned, need to copy rem bytes (rem < NBYTES)
+ * A loop would do only a byte at a time with possible branch
+ * mispredicts. Can't do an explicit LOAD dst,mask,or,STORE
+ * because can't assume read-access to dst. Instead, use
+ * STREST dst, which doesn't require read access to dst.
+ *
+ * This code should perform better than a simple loop on modern,
+ * wide-issue mips processors because the code has fewer branches and
+ * more instruction-level parallelism.
+ */
+#define bits t2
+ beqz len, .Ldone
+ ADD t1, dst, len # t1 is just past last byte of dst
+ li bits, 8*NBYTES
+ SLL rem, len, 3 # rem = number of bits to keep
+ LOAD(t0, 0(src))
+ SUB bits, bits, rem # bits = number of bits to discard
+ SHIFT_DISCARD t0, t0, bits
+ STREST(t0, -1(t1))
+ jr ra
+ move len, zero
+.Ldst_unaligned:
+ /*
+ * dst is unaligned
+ * t0 = src & ADDRMASK
+ * t1 = dst & ADDRMASK; T1 > 0
+ * len >= NBYTES
+ *
+ * Copy enough bytes to align dst
+ * Set match = (src and dst have same alignment)
+ */
+#define match rem
+ LDFIRST(t3, FIRST(0)(src))
+ ADD t2, zero, NBYTES
+ LDREST(t3, REST(0)(src))
+ SUB t2, t2, t1 # t2 = number of bytes copied
+ xor match, t0, t1
+ STFIRST(t3, FIRST(0)(dst))
+ beq len, t2, .Ldone
+ SUB len, len, t2
+ ADD dst, dst, t2
+ beqz match, .Lboth_aligned
+ ADD src, src, t2
+
+.Lsrc_unaligned_dst_aligned:
+ SRL t0, len, LOG_NBYTES+2 # +2 for 4 units/iter
+ beqz t0, .Lcleanup_src_unaligned
+ and rem, len, (4*NBYTES-1) # rem = len % 4*NBYTES
+1:
+/*
+ * Avoid consecutive LD*'s to the same register since some mips
+ * implementations can't issue them in the same cycle.
+ * It's OK to load FIRST(N+1) before REST(N) because the two addresses
+ * are to the same unit (unless src is aligned, but it's not).
+ */
+ LDFIRST(t0, FIRST(0)(src))
+ LDFIRST(t1, FIRST(1)(src))
+ SUB len, len, 4*NBYTES
+ LDREST(t0, REST(0)(src))
+ LDREST(t1, REST(1)(src))
+ LDFIRST(t2, FIRST(2)(src))
+ LDFIRST(t3, FIRST(3)(src))
+ LDREST(t2, REST(2)(src))
+ LDREST(t3, REST(3)(src))
+ ADD src, src, 4*NBYTES
+ STORE(t0, UNIT(0)(dst))
+ STORE(t1, UNIT(1)(dst))
+ STORE(t2, UNIT(2)(dst))
+ STORE(t3, UNIT(3)(dst))
+ .set reorder /* DADDI_WAR */
+ ADD dst, dst, 4*NBYTES
+ bne len, rem, 1b
+ .set noreorder
+
+.Lcleanup_src_unaligned:
+ beqz len, .Ldone
+ and rem, len, NBYTES-1 # rem = len % NBYTES
+ beq rem, len, .Lcopy_bytes
+ nop
+1:
+ LDFIRST(t0, FIRST(0)(src))
+ LDREST(t0, REST(0)(src))
+ ADD src, src, NBYTES
+ SUB len, len, NBYTES
+ STORE(t0, 0(dst))
+ .set reorder /* DADDI_WAR */
+ ADD dst, dst, NBYTES
+ bne len, rem, 1b
+ .set noreorder
+
+.Lcopy_bytes_checklen:
+ beqz len, .Ldone
+ nop
+.Lcopy_bytes:
+ /* 0 < len < NBYTES */
+#define COPY_BYTE(N) \
+ LOADB(t0, N(src)); \
+ SUB len, len, 1; \
+ beqz len, .Ldone; \
+ STOREB(t0, N(dst))
+
+ COPY_BYTE(0)
+ COPY_BYTE(1)
+ LOADB(t0, NBYTES-2(src))
+ SUB len, len, 1
+ jr ra
+ STOREB(t0, NBYTES-2(dst))
+.Ldone:
+ jr ra
+ nop
+ END(memcpy)
diff --git a/arch/mips/lib/memset.S b/arch/mips/lib/memset.S
new file mode 100644
index 0000000..d3c1c72
--- /dev/null
+++ b/arch/mips/lib/memset.S
@@ -0,0 +1,146 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1998, 1999, 2000 by Ralf Baechle
+ * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
+ * Copyright (C) 2007 by Maciej W. Rozycki
+ * Copyright (C) 2011, 2012 MIPS Technologies, Inc.
+ *
+ * Kernel-mode memset function without exceptions
+ * by Aleksey Kuleshov (rndfax at yandex.ru), 2015
+ */
+#include <asm/asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/regdef.h>
+
+#if LONGSIZE == 4
+#define LONG_S_L swl
+#define LONG_S_R swr
+#else
+#define LONG_S_L sdl
+#define LONG_S_R sdr
+#endif
+
+#define STORSIZE LONGSIZE
+#define STORMASK LONGMASK
+#define FILL64RG a1
+#define FILLPTRG t0
+
+/*
+ * memset(void *s, int c, size_t n)
+ *
+ * a0: start of area to clear
+ * a1: char to fill with
+ * a2: size of area to clear
+ */
+
+LEAF(memset)
+ beqz a1, 1f
+ move v0, a0 /* result */
+
+ andi a1, 0xff /* spread fillword */
+ LONG_SLL t1, a1, 8
+ or a1, t1
+ LONG_SLL t1, a1, 16
+#if LONGSIZE == 8
+ or a1, t1
+ LONG_SLL t1, a1, 32
+#endif
+ or a1, t1
+
+ .macro f_fill64 dst, offset, val
+ LONG_S \val, (\offset + 0 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 1 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 2 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 3 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 4 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 5 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 6 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 7 * STORSIZE)(\dst)
+#if (LONGSIZE == 4)
+ LONG_S \val, (\offset + 8 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 9 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 10 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 11 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 12 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 13 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 14 * STORSIZE)(\dst)
+ LONG_S \val, (\offset + 15 * STORSIZE)(\dst)
+#endif
+ .endm
+
+ .set noreorder
+ .align 5
+
+1:
+ sltiu t0, a2, STORSIZE /* very small region? */
+ bnez t0, .Lsmall_memset
+ andi t0, a0, STORMASK /* aligned? */
+
+ beqz t0, 1f
+ PTR_SUBU t0, STORSIZE /* alignment in bytes */
+
+#ifdef __MIPSEB__
+ LONG_S_L a1, (a0) /* make word/dword aligned */
+#else
+ LONG_S_R a1, (a0) /* make word/dword aligned */
+#endif
+ PTR_SUBU a0, t0 /* long align ptr */
+ PTR_ADDU a2, t0 /* correct size */
+
+1: ori t1, a2, 0x3f /* # of full blocks */
+ xori t1, 0x3f
+ beqz t1, .Lmemset_partial /* no block to fill */
+ andi t0, a2, 0x40-STORSIZE
+
+ PTR_ADDU t1, a0 /* end address */
+ .set reorder
+1: PTR_ADDIU a0, 64
+ f_fill64 a0, -64, FILL64RG
+ bne t1, a0, 1b
+ .set noreorder
+
+.Lmemset_partial:
+ PTR_LA t1, 2f /* where to start */
+#if LONGSIZE == 4
+ PTR_SUBU t1, FILLPTRG
+#else
+ .set noat
+ LONG_SRL AT, FILLPTRG, 1
+ PTR_SUBU t1, AT
+ .set at
+#endif
+ jr t1
+ PTR_ADDU a0, t0 /* dest ptr */
+
+ .set push
+ .set noreorder
+ .set nomacro
+ /* ... but first do longs ... */
+ f_fill64 a0, -64, FILL64RG
+2: .set pop
+ andi a2, STORMASK /* At most one long to go */
+
+ beqz a2, 1f
+ PTR_ADDU a0, a2 /* What's left */
+#ifdef __MIPSEB__
+ LONG_S_R a1, -1(a0)
+#else
+ LONG_S_L a1, -1(a0)
+#endif
+1: jr ra
+ move a2, zero
+
+.Lsmall_memset:
+ beqz a2, 2f
+ PTR_ADDU t1, a0, a2
+
+1: PTR_ADDIU a0, 1 /* fill bytewise */
+ bne t1, a0, 1b
+ sb a1, -1(a0)
+
+2: jr ra /* done */
+ move a2, zero
+ END(memset)
--
2.5.1
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