[PATCH] MIPS: import optimized string functions from Linux

[Aleksey Kuleshov <rndfax@yandex.ru>]

10x performance gain according to simple test on QEMU malta:
barebox:/ time memcpy 0xa0000000 0xa0001000 0x100000

Signed-off-by: Aleksey Kuleshov <rndfax@yandex.ru>
---
 arch/mips/Kconfig              |   8 ++
 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, 441 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..fdf62e8 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -331,6 +331,14 @@ config NMON_HELP
 	  Say yes here to get the nmon commands message on
 	  every nmon start.
 
+config MIPS_OPTIMIZED_STRING_FUNCTIONS
+	bool "use assembler optimized string functions"
+	default y
+	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..a797a74 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_OPTIMIZED_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..02ee189 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-$(CONFIG_MIPS_OPTIMIZED_STRING_FUNCTIONS) += memcpy.o
+obj-$(CONFIG_MIPS_OPTIMIZED_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@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@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@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)
-- 
2.6.2


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