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79 lines
1.4 KiB
ArmAsm
79 lines
1.4 KiB
ArmAsm
/*
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* COPYRIGHT: See COPYING in the top level directory
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* PROJECT: ReactOS Run-Time Library
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* PURPOSE: Memory functions for amd64
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* FILE: lib/rtl/i386/rtlswap.S
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* PROGRAMER: Timo Kreuzer (timo.kreuzer@reactos.org)
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*/
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/* INCLUDES ******************************************************************/
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#include <ndk/amd64/asmmacro.S>
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/* FUNCTIONS *****************************************************************/
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.intel_syntax noprefix
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/* SIZE_T
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* RtlCompareMemory(
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* IN CONST VOID *Source1, <rcx>
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* IN CONST VOID *Source2, <rdx>
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* IN SIZE_T Length <r8>
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* );
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*/
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.proc RtlCompareMemory
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/* Save registers */
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push rsi
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.pushreg rsi
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push rdi
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.pushreg rdi
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/* Setup registers for compare */
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mov rsi, rcx
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mov rdi, rdx
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/* Clear direction flag */
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cli
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/* Get number of qwords */
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mov rcx, r8
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shr rcx, 3
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jz 2f
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/* Compare qwords */
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repe cmpsq
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jnz 4f
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2: /* Compare rest */
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mov rcx, r8
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and rcx, 7
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jz 3f
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repe cmpsb
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jnz 5f
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3: /* All equal */
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/* Return the full count */
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mov rax, rcx
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jmp 6f
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4: /* Not equal after comparing qwords */
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/* Compare the last qword */
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sub rsi, 8
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sub rdi, 8
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mov rcx, 8
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repe cmpsb
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5: /* Not equal after comparing bytes */
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/* Return difference */
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sub rdi, rdx
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dec rdi
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mov rax, rdi
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6: /* Cleanup and return */
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pop rdi
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pop rsi
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ret
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.endproc
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