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authorZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
committerZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
commit5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 (patch)
tree4470480d904b65cf14ca524f96f79eca818c3eaf /REORG.TODO/sysdeps/arm/memmove.S
parent199fc19d3aaaf57944ef036e15904febe877fc93 (diff)
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Prepare for radical source tree reorganization.zack/build-layout-experiment
All top-level files and directories are moved into a temporary storage directory, REORG.TODO, except for files that will certainly still exist in their current form at top level when we're done (COPYING, COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which are moved to the new directory OldChangeLogs, instead), and the generated file INSTALL (which is just deleted; in the new order, there will be no generated files checked into version control).
Diffstat (limited to 'REORG.TODO/sysdeps/arm/memmove.S')
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diff --git a/REORG.TODO/sysdeps/arm/memmove.S b/REORG.TODO/sysdeps/arm/memmove.S
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+/* Copyright (C) 2006-2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ Contributed by MontaVista Software, Inc. (written by Nicolas Pitre)
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* Thumb requires excessive IT insns here. */
+#define NO_THUMB
+#include <sysdep.h>
+#include <arm-features.h>
+
+/*
+ * Data preload for architectures that support it (ARM V5TE and above)
+ */
+#if (!defined (__ARM_ARCH_2__) && !defined (__ARM_ARCH_3__) \
+ && !defined (__ARM_ARCH_3M__) && !defined (__ARM_ARCH_4__) \
+ && !defined (__ARM_ARCH_4T__) && !defined (__ARM_ARCH_5__) \
+ && !defined (__ARM_ARCH_5T__))
+#define PLD(code...) code
+#else
+#define PLD(code...)
+#endif
+
+/*
+ * This can be used to enable code to cacheline align the source pointer.
+ * Experiments on tested architectures (StrongARM and XScale) didn't show
+ * this a worthwhile thing to do. That might be different in the future.
+ */
+//#define CALGN(code...) code
+#define CALGN(code...)
+
+/*
+ * Endian independent macros for shifting bytes within registers.
+ */
+#ifndef __ARMEB__
+#define PULL lsr
+#define PUSH lsl
+#else
+#define PULL lsl
+#define PUSH lsr
+#endif
+
+ .text
+ .syntax unified
+
+/*
+ * Prototype: void *memmove(void *dest, const void *src, size_t n);
+ *
+ * Note:
+ *
+ * If the memory regions don't overlap, we simply branch to memcpy which is
+ * normally a bit faster. Otherwise the copy is done going downwards.
+ */
+
+ENTRY(memmove)
+
+ subs ip, r0, r1
+ cmphi r2, ip
+#if !IS_IN (libc)
+ bls memcpy
+#else
+ bls HIDDEN_JUMPTARGET(memcpy)
+#endif
+
+ push {r0, r4, lr}
+ cfi_adjust_cfa_offset (12)
+ cfi_rel_offset (r4, 4)
+ cfi_rel_offset (lr, 8)
+
+ cfi_remember_state
+
+ add r1, r1, r2
+ add r0, r0, r2
+ subs r2, r2, #4
+ blt 8f
+ ands ip, r0, #3
+ PLD( pld [r1, #-4] )
+ bne 9f
+ ands ip, r1, #3
+ bne 10f
+
+1: subs r2, r2, #(28)
+ push {r5 - r8}
+ cfi_adjust_cfa_offset (16)
+ cfi_rel_offset (r5, 0)
+ cfi_rel_offset (r6, 4)
+ cfi_rel_offset (r7, 8)
+ cfi_rel_offset (r8, 12)
+ blt 5f
+
+ CALGN( ands ip, r1, #31 )
+ CALGN( sbcsne r4, ip, r2 ) @ C is always set here
+ CALGN( bcs 2f )
+ CALGN( adr r4, 6f )
+ CALGN( subs r2, r2, ip ) @ C is set here
+#ifndef ARM_ALWAYS_BX
+ CALGN( add pc, r4, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2))
+#else
+ CALGN( add r4, r4, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2))
+ CALGN( bx r4 )
+#endif
+
+ PLD( pld [r1, #-4] )
+2: PLD( subs r2, r2, #96 )
+ PLD( pld [r1, #-32] )
+ PLD( blt 4f )
+ PLD( pld [r1, #-64] )
+ PLD( pld [r1, #-96] )
+
+3: PLD( pld [r1, #-128] )
+4: ldmdb r1!, {r3, r4, r5, r6, r7, r8, ip, lr}
+ subs r2, r2, #32
+ stmdb r0!, {r3, r4, r5, r6, r7, r8, ip, lr}
+ bge 3b
+ PLD( cmn r2, #96 )
+ PLD( bge 4b )
+
+5: ands ip, r2, #28
+ rsb ip, ip, #32
+#ifndef ARM_ALWAYS_BX
+ /* C is always clear here. */
+ addne pc, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
+ b 7f
+#else
+ beq 7f
+ push {r10}
+ cfi_adjust_cfa_offset (4)
+ cfi_rel_offset (r10, 0)
+0: add r10, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
+ /* If alignment is not perfect, then there will be some
+ padding (nop) instructions between this BX and label 6.
+ The computation above assumed that two instructions
+ later is exactly the right spot. */
+ add r10, #(6f - (0b + PC_OFS))
+ bx r10
+#endif
+ .p2align ARM_BX_ALIGN_LOG2
+6: nop
+ .p2align ARM_BX_ALIGN_LOG2
+ ldr r3, [r1, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
+ ldr r4, [r1, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
+ ldr r5, [r1, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
+ ldr r6, [r1, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
+ ldr r7, [r1, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
+ ldr r8, [r1, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
+ ldr lr, [r1, #-4]!
+
+#ifndef ARM_ALWAYS_BX
+ add pc, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
+ nop
+#else
+0: add r10, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
+ /* If alignment is not perfect, then there will be some
+ padding (nop) instructions between this BX and label 66.
+ The computation above assumed that two instructions
+ later is exactly the right spot. */
+ add r10, #(66f - (0b + PC_OFS))
+ bx r10
+#endif
+ .p2align ARM_BX_ALIGN_LOG2
+66: nop
+ .p2align ARM_BX_ALIGN_LOG2
+ str r3, [r0, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
+ str r4, [r0, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
+ str r5, [r0, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
+ str r6, [r0, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
+ str r7, [r0, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
+ str r8, [r0, #-4]!
+ .p2align ARM_BX_ALIGN_LOG2
+ str lr, [r0, #-4]!
+
+#ifdef ARM_ALWAYS_BX
+ pop {r10}
+ cfi_adjust_cfa_offset (-4)
+ cfi_restore (r10)
+#endif
+
+ CALGN( bcs 2b )
+
+7: pop {r5 - r8}
+ cfi_adjust_cfa_offset (-16)
+ cfi_restore (r5)
+ cfi_restore (r6)
+ cfi_restore (r7)
+ cfi_restore (r8)
+
+8: movs r2, r2, lsl #31
+ ldrbne r3, [r1, #-1]!
+ ldrbcs r4, [r1, #-1]!
+ ldrbcs ip, [r1, #-1]
+ strbne r3, [r0, #-1]!
+ strbcs r4, [r0, #-1]!
+ strbcs ip, [r0, #-1]
+
+#if ((defined (__ARM_ARCH_4T__) && defined (__THUMB_INTERWORK__)) \
+ || defined (ARM_ALWAYS_BX))
+ pop {r0, r4, lr}
+ cfi_adjust_cfa_offset (-12)
+ cfi_restore (r4)
+ cfi_restore (lr)
+ bx lr
+#else
+ pop {r0, r4, pc}
+#endif
+
+ cfi_restore_state
+
+9: cmp ip, #2
+ ldrbgt r3, [r1, #-1]!
+ ldrbge r4, [r1, #-1]!
+ ldrb lr, [r1, #-1]!
+ strbgt r3, [r0, #-1]!
+ strbge r4, [r0, #-1]!
+ subs r2, r2, ip
+ strb lr, [r0, #-1]!
+ blt 8b
+ ands ip, r1, #3
+ beq 1b
+
+10: bic r1, r1, #3
+ cmp ip, #2
+ ldr r3, [r1, #0]
+ beq 17f
+ blt 18f
+
+
+ .macro backward_copy_shift push pull
+
+ subs r2, r2, #28
+ blt 14f
+
+ CALGN( ands ip, r1, #31 )
+ CALGN( rsb ip, ip, #32 )
+ CALGN( sbcsne r4, ip, r2 ) @ C is always set here
+ CALGN( subcc r2, r2, ip )
+ CALGN( bcc 15f )
+
+11: push {r5 - r8, r10}
+ cfi_adjust_cfa_offset (20)
+ cfi_rel_offset (r5, 0)
+ cfi_rel_offset (r6, 4)
+ cfi_rel_offset (r7, 8)
+ cfi_rel_offset (r8, 12)
+ cfi_rel_offset (r10, 16)
+
+ PLD( pld [r1, #-4] )
+ PLD( subs r2, r2, #96 )
+ PLD( pld [r1, #-32] )
+ PLD( blt 13f )
+ PLD( pld [r1, #-64] )
+ PLD( pld [r1, #-96] )
+
+12: PLD( pld [r1, #-128] )
+13: ldmdb r1!, {r7, r8, r10, ip}
+ mov lr, r3, PUSH #\push
+ subs r2, r2, #32
+ ldmdb r1!, {r3, r4, r5, r6}
+ orr lr, lr, ip, PULL #\pull
+ mov ip, ip, PUSH #\push
+ orr ip, ip, r10, PULL #\pull
+ mov r10, r10, PUSH #\push
+ orr r10, r10, r8, PULL #\pull
+ mov r8, r8, PUSH #\push
+ orr r8, r8, r7, PULL #\pull
+ mov r7, r7, PUSH #\push
+ orr r7, r7, r6, PULL #\pull
+ mov r6, r6, PUSH #\push
+ orr r6, r6, r5, PULL #\pull
+ mov r5, r5, PUSH #\push
+ orr r5, r5, r4, PULL #\pull
+ mov r4, r4, PUSH #\push
+ orr r4, r4, r3, PULL #\pull
+ stmdb r0!, {r4 - r8, r10, ip, lr}
+ bge 12b
+ PLD( cmn r2, #96 )
+ PLD( bge 13b )
+
+ pop {r5 - r8, r10}
+ cfi_adjust_cfa_offset (-20)
+ cfi_restore (r5)
+ cfi_restore (r6)
+ cfi_restore (r7)
+ cfi_restore (r8)
+ cfi_restore (r10)
+
+14: ands ip, r2, #28
+ beq 16f
+
+15: mov lr, r3, PUSH #\push
+ ldr r3, [r1, #-4]!
+ subs ip, ip, #4
+ orr lr, lr, r3, PULL #\pull
+ str lr, [r0, #-4]!
+ bgt 15b
+ CALGN( cmp r2, #0 )
+ CALGN( bge 11b )
+
+16: add r1, r1, #(\pull / 8)
+ b 8b
+
+ .endm
+
+
+ backward_copy_shift push=8 pull=24
+
+17: backward_copy_shift push=16 pull=16
+
+18: backward_copy_shift push=24 pull=8
+
+
+END(memmove)
+libc_hidden_builtin_def (memmove)