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+++ Libc/Libc-825.26/arm/string/bzero_CortexA9.s
@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) 2009 Apple Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ *
+ * This file implements the following functions for the Cortex-A9 processor:
+ *
+ * void bzero(void * destination,
+ * size_t length);
+ *
+ * void __bzero(void * destination,
+ * size_t length);
+ *
+ * zeros out a buffer length bytes long, beginning at the address destination.
+ *
+ * void *memset(void * destination,
+ * int value,
+ * size_t n);
+ *
+ * writes value converted to an unsigned char to n successive bytes, beginning
+ * at destination.
+ */
+
+#include <arm/arch.h>
+#if defined _ARM_ARCH_7
+
+/*****************************************************************************
+ * Macros *
+ *****************************************************************************/
+
+#define A9_ENTRY(name) \
+ .align 2;\
+ .globl _ ## name ## $VARIANT$CortexA9;\
+ _ ## name ## $VARIANT$CortexA9:
+
+#define ESTABLISH_FRAME \
+ push {r0,r4,r7,lr};\
+ add r7, sp, #8
+
+#define CLEAR_FRAME_AND_RETURN \
+ pop {r0,r4,r7,pc}
+
+#define ADDITIONAL_CALLEE_SAVE_REGISTERS {r5,r6,r8}
+
+#define STORE_REGISTERS {r1,r3,r4,r5,r6,r8,r9,ip}
+
+/*****************************************************************************
+ * entry points *
+ *****************************************************************************/
+
+.text
+.syntax unified
+.code 32
+
+A9_ENTRY(__bzero)
+A9_ENTRY(bzero)
+ mov r2, r1
+ eor r1, r1
+
+A9_ENTRY(memset)
+// Early out if fewer than four bytes are to be set. Otherwise, store up to
+// three bytes to align the destination pointer to a word boundary.
+ ESTABLISH_FRAME
+ and r1, #0xff
+ subs r2, #4
+ orr r1, r1, r1, lsl #8
+ blo L_lengthLessThanFour
+ orr r1, r1, r1, lsl #16
+0: tst r0, #0x3
+ beq L_wordAligned
+ strb r1, [r0],#1
+ subs r2, #1
+ bhs 0b
+L_lengthLessThanFour:
+ adds r2, #4
+ beq 1f
+0: strb r1, [r0],#1
+ subs r2, #1
+ bne 0b
+1: CLEAR_FRAME_AND_RETURN
+
+L_wordAligned:
+// Destination pointer has word alignment. Early out if fewer than 64 bytes
+// are to be set. Otherwise, store up to 28 bytes to align the destination
+// pointer to a cacheline boundary.
+ mov r3, r1
+ mov r4, r1
+ subs r2, #0x3c
+ mov r9, r1
+ blo L_lengthLessThanSixtyFour
+0: tst r0, #0x1c
+ beq L_cachelineAligned
+ str r1, [r0],#4
+ subs r2, #4
+ bhs 0b
+L_lengthLessThanSixtyFour:
+ tst r2, #0x30
+ beq 1f
+0: stm r0!, {r1,r3,r4,r9}
+ sub r2, #0x10
+ tst r2, #0x30
+ bne 0b
+1: tst r2, #0xf
+ beq 2f
+ lsls ip, r2, #29
+ stmcs r0!, {r1,r3}
+ strmi r1, [r0],#4
+ lsls ip, r2, #31
+ strhcs r1, [r0],#2
+ strbmi r1, [r0]
+2: CLEAR_FRAME_AND_RETURN
+
+L_cachelineAligned:
+// Main unrolled loop; stores two complete cachelines per iteration.
+ push ADDITIONAL_CALLEE_SAVE_REGISTERS
+ mov r5, r1
+ mov r6, r1
+ mov r8, r1
+ mov ip, r1
+.align 4
+0: stm r0!, STORE_REGISTERS
+ subs r2, #0x40
+ stm r0!, STORE_REGISTERS
+ bhs 0b
+ pop ADDITIONAL_CALLEE_SAVE_REGISTERS
+ b L_lengthLessThanSixtyFour
+
+#endif // defined _ARM_ARCH_7