71 lines
1.5 KiB
NASM
71 lines
1.5 KiB
NASM
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title "Zero Page"
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;++
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;
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; Copyright (c) 2001 Microsoft Corporation
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;
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; Module Name:
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;
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; zero.asm
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;
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; Abstract:
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;
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; This module implements the architecture dependent code necessary to
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; zero a page of memory is the fastest possible way.
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;
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; Author:
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;
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; David N. Cutler (davec) 9-Jan-2001
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;
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; Environment:
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;
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; Kernel mode only.
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;
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;--
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include ksamd64.inc
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subttl "Zero Page"
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;++
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;
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; VOID
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; KeZeroPage (
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; IN PVOID PageBase
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; )
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;
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; Routine Description:
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;
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; This routine zeros the specfied page of memory using nontemporal moves.
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;
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; Arguments:
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;
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; PageBase (rcx) - Supplies the address of the page to zero.
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;
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; Return Value:
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;
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; None.
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;
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;--
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LEAF_ENTRY KeZeroPage, _TEXT$00
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pxor xmm0, xmm0 ; clear register
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mov eax, PAGE_SIZE / 128 ; compute loop count
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KeZP10: movntdq 0[rcx], xmm0 ; zero 128-byte block
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movntdq 16[rcx], xmm0 ;
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movntdq 32[rcx], xmm0 ;
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movntdq 48[rcx], xmm0 ;
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movntdq 64[rcx], xmm0 ;
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movntdq 80[rcx], xmm0 ;
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movntdq 96[rcx], xmm0 ;
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movntdq 112[rcx], xmm0 ;
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add rcx, 128 ; advance to next block
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dec eax ; decrement loop count
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jnz short KeZP10 ; if nz, more bytes to zero
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sfence ; force stores to complete
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ret ;
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LEAF_END KeZeroPage, _TEXT$00
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end
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