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-rw-r--r--lib/libc/arch/arm/string/_memcpy.S468
1 files changed, 468 insertions, 0 deletions
diff --git a/lib/libc/arch/arm/string/_memcpy.S b/lib/libc/arch/arm/string/_memcpy.S
new file mode 100644
index 00000000000..11fb564e778
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+++ b/lib/libc/arch/arm/string/_memcpy.S
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+/* $NetBSD: _memcpy.S,v 1.4 2003/04/05 23:08:52 bjh21 Exp $ */
+
+/*-
+ * Copyright (c) 1997 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Neil A. Carson and Mark Brinicombe
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the NetBSD
+ * Foundation, Inc. and its contributors.
+ * 4. Neither the name of The NetBSD Foundation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <machine/asm.h>
+
+/*
+ * This is one fun bit of code ...
+ * Some easy listening music is suggested while trying to understand this
+ * code e.g. Iron Maiden
+ *
+ * For anyone attempting to understand it :
+ *
+ * The core code is implemented here with simple stubs for memcpy()
+ * memmove() and bcopy().
+ *
+ * All local labels are prefixed with Lmemcpy_
+ * Following the prefix a label starting f is used in the forward copy code
+ * while a label using b is used in the backwards copy code
+ * The source and destination addresses determine whether a forward or
+ * backward copy is performed.
+ * Separate bits of code are used to deal with the following situations
+ * for both the forward and backwards copy.
+ * unaligned source address
+ * unaligned destination address
+ * Separate copy routines are used to produce an optimised result for each
+ * of these cases.
+ * The copy code will use LDM/STM instructions to copy up to 32 bytes at
+ * a time where possible.
+ *
+ * Note: r12 (aka ip) can be trashed during the function along with
+ * r0-r3 although r0-r2 have defined uses i.e. src, dest, len through out.
+ * Additional registers are preserved prior to use i.e. r4, r5 & lr
+ *
+ * Apologies for the state of the comments ;-)
+ */
+
+ENTRY(_memcpy)
+ /* Determine copy direction */
+ cmp r1, r0
+ bcc .Lmemcpy_backwards
+
+ moveq r0, #0 /* Quick abort for len=0 */
+ moveq pc, lr
+
+ stmdb sp!, {r0, lr} /* memcpy() returns dest addr */
+ subs r2, r2, #4
+ blt .Lmemcpy_fl4 /* less than 4 bytes */
+ ands r12, r0, #3
+ bne .Lmemcpy_fdestul /* oh unaligned destination addr */
+ ands r12, r1, #3
+ bne .Lmemcpy_fsrcul /* oh unaligned source addr */
+
+.Lmemcpy_ft8:
+ /* We have aligned source and destination */
+ subs r2, r2, #8
+ blt .Lmemcpy_fl12 /* less than 12 bytes (4 from above) */
+ subs r2, r2, #0x14
+ blt .Lmemcpy_fl32 /* less than 32 bytes (12 from above) */
+ stmdb sp!, {r4} /* borrow r4 */
+
+ /* blat 32 bytes at a time */
+ /* XXX for really big copies perhaps we should use more registers */
+.Lmemcpy_floop32:
+ ldmia r1!, {r3, r4, r12, lr}
+ stmia r0!, {r3, r4, r12, lr}
+ ldmia r1!, {r3, r4, r12, lr}
+ stmia r0!, {r3, r4, r12, lr}
+ subs r2, r2, #0x20
+ bge .Lmemcpy_floop32
+
+ cmn r2, #0x10
+ ldmgeia r1!, {r3, r4, r12, lr} /* blat a remaining 16 bytes */
+ stmgeia r0!, {r3, r4, r12, lr}
+ subge r2, r2, #0x10
+ ldmia sp!, {r4} /* return r4 */
+
+.Lmemcpy_fl32:
+ adds r2, r2, #0x14
+
+ /* blat 12 bytes at a time */
+.Lmemcpy_floop12:
+ ldmgeia r1!, {r3, r12, lr}
+ stmgeia r0!, {r3, r12, lr}
+ subges r2, r2, #0x0c
+ bge .Lmemcpy_floop12
+
+.Lmemcpy_fl12:
+ adds r2, r2, #8
+ blt .Lmemcpy_fl4
+
+ subs r2, r2, #4
+ ldrlt r3, [r1], #4
+ strlt r3, [r0], #4
+ ldmgeia r1!, {r3, r12}
+ stmgeia r0!, {r3, r12}
+ subge r2, r2, #4
+
+.Lmemcpy_fl4:
+ /* less than 4 bytes to go */
+ adds r2, r2, #4
+ ldmeqia sp!, {r0, pc} /* done */
+
+ /* copy the crud byte at a time */
+ cmp r2, #2
+ ldrb r3, [r1], #1
+ strb r3, [r0], #1
+ ldrgeb r3, [r1], #1
+ strgeb r3, [r0], #1
+ ldrgtb r3, [r1], #1
+ strgtb r3, [r0], #1
+ ldmia sp!, {r0, pc}
+
+ /* erg - unaligned destination */
+.Lmemcpy_fdestul:
+ rsb r12, r12, #4
+ cmp r12, #2
+
+ /* align destination with byte copies */
+ ldrb r3, [r1], #1
+ strb r3, [r0], #1
+ ldrgeb r3, [r1], #1
+ strgeb r3, [r0], #1
+ ldrgtb r3, [r1], #1
+ strgtb r3, [r0], #1
+ subs r2, r2, r12
+ blt .Lmemcpy_fl4 /* less the 4 bytes */
+
+ ands r12, r1, #3
+ beq .Lmemcpy_ft8 /* we have an aligned source */
+
+ /* erg - unaligned source */
+ /* This is where it gets nasty ... */
+.Lmemcpy_fsrcul:
+ bic r1, r1, #3
+ ldr lr, [r1], #4
+ cmp r12, #2
+ bgt .Lmemcpy_fsrcul3
+ beq .Lmemcpy_fsrcul2
+ cmp r2, #0x0c
+ blt .Lmemcpy_fsrcul1loop4
+ sub r2, r2, #0x0c
+ stmdb sp!, {r4, r5}
+
+.Lmemcpy_fsrcul1loop16:
+ mov r3, lr, lsr #8
+ ldmia r1!, {r4, r5, r12, lr}
+ orr r3, r3, r4, lsl #24
+ mov r4, r4, lsr #8
+ orr r4, r4, r5, lsl #24
+ mov r5, r5, lsr #8
+ orr r5, r5, r12, lsl #24
+ mov r12, r12, lsr #8
+ orr r12, r12, lr, lsl #24
+ stmia r0!, {r3-r5, r12}
+ subs r2, r2, #0x10
+ bge .Lmemcpy_fsrcul1loop16
+ ldmia sp!, {r4, r5}
+ adds r2, r2, #0x0c
+ blt .Lmemcpy_fsrcul1l4
+
+.Lmemcpy_fsrcul1loop4:
+ mov r12, lr, lsr #8
+ ldr lr, [r1], #4
+ orr r12, r12, lr, lsl #24
+ str r12, [r0], #4
+ subs r2, r2, #4
+ bge .Lmemcpy_fsrcul1loop4
+
+.Lmemcpy_fsrcul1l4:
+ sub r1, r1, #3
+ b .Lmemcpy_fl4
+
+.Lmemcpy_fsrcul2:
+ cmp r2, #0x0c
+ blt .Lmemcpy_fsrcul2loop4
+ sub r2, r2, #0x0c
+ stmdb sp!, {r4, r5}
+
+.Lmemcpy_fsrcul2loop16:
+ mov r3, lr, lsr #16
+ ldmia r1!, {r4, r5, r12, lr}
+ orr r3, r3, r4, lsl #16
+ mov r4, r4, lsr #16
+ orr r4, r4, r5, lsl #16
+ mov r5, r5, lsr #16
+ orr r5, r5, r12, lsl #16
+ mov r12, r12, lsr #16
+ orr r12, r12, lr, lsl #16
+ stmia r0!, {r3-r5, r12}
+ subs r2, r2, #0x10
+ bge .Lmemcpy_fsrcul2loop16
+ ldmia sp!, {r4, r5}
+ adds r2, r2, #0x0c
+ blt .Lmemcpy_fsrcul2l4
+
+.Lmemcpy_fsrcul2loop4:
+ mov r12, lr, lsr #16
+ ldr lr, [r1], #4
+ orr r12, r12, lr, lsl #16
+ str r12, [r0], #4
+ subs r2, r2, #4
+ bge .Lmemcpy_fsrcul2loop4
+
+.Lmemcpy_fsrcul2l4:
+ sub r1, r1, #2
+ b .Lmemcpy_fl4
+
+.Lmemcpy_fsrcul3:
+ cmp r2, #0x0c
+ blt .Lmemcpy_fsrcul3loop4
+ sub r2, r2, #0x0c
+ stmdb sp!, {r4, r5}
+
+.Lmemcpy_fsrcul3loop16:
+ mov r3, lr, lsr #24
+ ldmia r1!, {r4, r5, r12, lr}
+ orr r3, r3, r4, lsl #8
+ mov r4, r4, lsr #24
+ orr r4, r4, r5, lsl #8
+ mov r5, r5, lsr #24
+ orr r5, r5, r12, lsl #8
+ mov r12, r12, lsr #24
+ orr r12, r12, lr, lsl #8
+ stmia r0!, {r3-r5, r12}
+ subs r2, r2, #0x10
+ bge .Lmemcpy_fsrcul3loop16
+ ldmia sp!, {r4, r5}
+ adds r2, r2, #0x0c
+ blt .Lmemcpy_fsrcul3l4
+
+.Lmemcpy_fsrcul3loop4:
+ mov r12, lr, lsr #24
+ ldr lr, [r1], #4
+ orr r12, r12, lr, lsl #8
+ str r12, [r0], #4
+ subs r2, r2, #4
+ bge .Lmemcpy_fsrcul3loop4
+
+.Lmemcpy_fsrcul3l4:
+ sub r1, r1, #1
+ b .Lmemcpy_fl4
+
+.Lmemcpy_backwards:
+ add r1, r1, r2
+ add r0, r0, r2
+ subs r2, r2, #4
+ blt .Lmemcpy_bl4 /* less than 4 bytes */
+ ands r12, r0, #3
+ bne .Lmemcpy_bdestul /* oh unaligned destination addr */
+ ands r12, r1, #3
+ bne .Lmemcpy_bsrcul /* oh unaligned source addr */
+
+.Lmemcpy_bt8:
+ /* We have aligned source and destination */
+ subs r2, r2, #8
+ blt .Lmemcpy_bl12 /* less than 12 bytes (4 from above) */
+ stmdb sp!, {r4, lr}
+ subs r2, r2, #0x14 /* less than 32 bytes (12 from above) */
+ blt .Lmemcpy_bl32
+
+ /* blat 32 bytes at a time */
+ /* XXX for really big copies perhaps we should use more registers */
+.Lmemcpy_bloop32:
+ ldmdb r1!, {r3, r4, r12, lr}
+ stmdb r0!, {r3, r4, r12, lr}
+ ldmdb r1!, {r3, r4, r12, lr}
+ stmdb r0!, {r3, r4, r12, lr}
+ subs r2, r2, #0x20
+ bge .Lmemcpy_bloop32
+
+.Lmemcpy_bl32:
+ cmn r2, #0x10
+ ldmgedb r1!, {r3, r4, r12, lr} /* blat a remaining 16 bytes */
+ stmgedb r0!, {r3, r4, r12, lr}
+ subge r2, r2, #0x10
+ adds r2, r2, #0x14
+ ldmgedb r1!, {r3, r12, lr} /* blat a remaining 12 bytes */
+ stmgedb r0!, {r3, r12, lr}
+ subge r2, r2, #0x0c
+ ldmia sp!, {r4, lr}
+
+.Lmemcpy_bl12:
+ adds r2, r2, #8
+ blt .Lmemcpy_bl4
+ subs r2, r2, #4
+ ldrlt r3, [r1, #-4]!
+ strlt r3, [r0, #-4]!
+ ldmgedb r1!, {r3, r12}
+ stmgedb r0!, {r3, r12}
+ subge r2, r2, #4
+
+.Lmemcpy_bl4:
+ /* less than 4 bytes to go */
+ adds r2, r2, #4
+ moveq pc, lr /* done */
+
+ /* copy the crud byte at a time */
+ cmp r2, #2
+ ldrb r3, [r1, #-1]!
+ strb r3, [r0, #-1]!
+ ldrgeb r3, [r1, #-1]!
+ strgeb r3, [r0, #-1]!
+ ldrgtb r3, [r1, #-1]!
+ strgtb r3, [r0, #-1]!
+ mov pc, lr
+
+ /* erg - unaligned destination */
+.Lmemcpy_bdestul:
+ cmp r12, #2
+
+ /* align destination with byte copies */
+ ldrb r3, [r1, #-1]!
+ strb r3, [r0, #-1]!
+ ldrgeb r3, [r1, #-1]!
+ strgeb r3, [r0, #-1]!
+ ldrgtb r3, [r1, #-1]!
+ strgtb r3, [r0, #-1]!
+ subs r2, r2, r12
+ blt .Lmemcpy_bl4 /* less than 4 bytes to go */
+ ands r12, r1, #3
+ beq .Lmemcpy_bt8 /* we have an aligned source */
+
+ /* erg - unaligned source */
+ /* This is where it gets nasty ... */
+.Lmemcpy_bsrcul:
+ bic r1, r1, #3
+ ldr r3, [r1, #0]
+ cmp r12, #2
+ blt .Lmemcpy_bsrcul1
+ beq .Lmemcpy_bsrcul2
+ cmp r2, #0x0c
+ blt .Lmemcpy_bsrcul3loop4
+ sub r2, r2, #0x0c
+ stmdb sp!, {r4, r5, lr}
+
+.Lmemcpy_bsrcul3loop16:
+ mov lr, r3, lsl #8
+ ldmdb r1!, {r3-r5, r12}
+ orr lr, lr, r12, lsr #24
+ mov r12, r12, lsl #8
+ orr r12, r12, r5, lsr #24
+ mov r5, r5, lsl #8
+ orr r5, r5, r4, lsr #24
+ mov r4, r4, lsl #8
+ orr r4, r4, r3, lsr #24
+ stmdb r0!, {r4, r5, r12, lr}
+ subs r2, r2, #0x10
+ bge .Lmemcpy_bsrcul3loop16
+ ldmia sp!, {r4, r5, lr}
+ adds r2, r2, #0x0c
+ blt .Lmemcpy_bsrcul3l4
+
+.Lmemcpy_bsrcul3loop4:
+ mov r12, r3, lsl #8
+ ldr r3, [r1, #-4]!
+ orr r12, r12, r3, lsr #24
+ str r12, [r0, #-4]!
+ subs r2, r2, #4
+ bge .Lmemcpy_bsrcul3loop4
+
+.Lmemcpy_bsrcul3l4:
+ add r1, r1, #3
+ b .Lmemcpy_bl4
+
+.Lmemcpy_bsrcul2:
+ cmp r2, #0x0c
+ blt .Lmemcpy_bsrcul2loop4
+ sub r2, r2, #0x0c
+ stmdb sp!, {r4, r5, lr}
+
+.Lmemcpy_bsrcul2loop16:
+ mov lr, r3, lsl #16
+ ldmdb r1!, {r3-r5, r12}
+ orr lr, lr, r12, lsr #16
+ mov r12, r12, lsl #16
+ orr r12, r12, r5, lsr #16
+ mov r5, r5, lsl #16
+ orr r5, r5, r4, lsr #16
+ mov r4, r4, lsl #16
+ orr r4, r4, r3, lsr #16
+ stmdb r0!, {r4, r5, r12, lr}
+ subs r2, r2, #0x10
+ bge .Lmemcpy_bsrcul2loop16
+ ldmia sp!, {r4, r5, lr}
+ adds r2, r2, #0x0c
+ blt .Lmemcpy_bsrcul2l4
+
+.Lmemcpy_bsrcul2loop4:
+ mov r12, r3, lsl #16
+ ldr r3, [r1, #-4]!
+ orr r12, r12, r3, lsr #16
+ str r12, [r0, #-4]!
+ subs r2, r2, #4
+ bge .Lmemcpy_bsrcul2loop4
+
+.Lmemcpy_bsrcul2l4:
+ add r1, r1, #2
+ b .Lmemcpy_bl4
+
+.Lmemcpy_bsrcul1:
+ cmp r2, #0x0c
+ blt .Lmemcpy_bsrcul1loop4
+ sub r2, r2, #0x0c
+ stmdb sp!, {r4, r5, lr}
+
+.Lmemcpy_bsrcul1loop32:
+ mov lr, r3, lsl #24
+ ldmdb r1!, {r3-r5, r12}
+ orr lr, lr, r12, lsr #8
+ mov r12, r12, lsl #24
+ orr r12, r12, r5, lsr #8
+ mov r5, r5, lsl #24
+ orr r5, r5, r4, lsr #8
+ mov r4, r4, lsl #24
+ orr r4, r4, r3, lsr #8
+ stmdb r0!, {r4, r5, r12, lr}
+ subs r2, r2, #0x10
+ bge .Lmemcpy_bsrcul1loop32
+ ldmia sp!, {r4, r5, lr}
+ adds r2, r2, #0x0c
+ blt .Lmemcpy_bsrcul1l4
+
+.Lmemcpy_bsrcul1loop4:
+ mov r12, r3, lsl #24
+ ldr r3, [r1, #-4]!
+ orr r12, r12, r3, lsr #8
+ str r12, [r0, #-4]!
+ subs r2, r2, #4
+ bge .Lmemcpy_bsrcul1loop4
+
+.Lmemcpy_bsrcul1l4:
+ add r1, r1, #1
+ b .Lmemcpy_bl4
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