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; Licensed to the .NET Foundation under one or more agreements.
; The .NET Foundation licenses this file to you under the MIT license.
; See the LICENSE file in the project root for more information.
; ==++==
;
;
; ==--==
; ***********************************************************************
; File: CrtHelpers.asm, see history in asmhelpers.asm
;
; ***********************************************************************
include AsmMacros.inc
extern memset:proc
extern memmove:proc
; JIT_MemSet/JIT_MemCpy
;
; It is IMPORTANT that the exception handling code is able to find these guys
; on the stack, but on windows platforms we can just defer to the platform
; implementation.
;
; void JIT_MemSet(void* dest, int c, size_t count)
;
; Purpose:
; Sets the first "count" bytes of the block of memory pointed byte
; "dest" to the specified value (interpreted as an unsigned char).
;
; Entry:
; RCX: void* dest - Pointer to the block of memory to fill.
; RDX: int c - Value to be set.
; R8: size_t count - Number of bytes to be set to the value.
;
; Exit:
;
; Uses:
;
; Exceptions:
;
LEAF_ENTRY JIT_MemSet, _TEXT
test r8, r8 ; check if count is zero
jz Exit_MemSet ; if zero, no bytes to set
cmp byte ptr [rcx], 0 ; check dest for null
jmp memset ; forward to the CRT implementation
Exit_MemSet:
ret
LEAF_END_MARKED JIT_MemSet, _TEXT
; void JIT_MemCpy(void* dest, const void* src, size_t count)
;
; Purpose:
; Copies the values of "count" bytes from the location pointed to
; by "src" to the memory block pointed by "dest".
;
; Entry:
; RCX: void* dest - Pointer to the destination array where content is to be copied.
; RDX: const void* src - Pointer to the source of the data to be copied.
; R8: size_t count - Number of bytes to copy.
;
; Exit:
;
; Uses:
;
; Exceptions:
;
LEAF_ENTRY JIT_MemCpy, _TEXT
test r8, r8 ; check if count is zero
jz Exit_MemCpy ; if zero, no bytes to copy
cmp byte ptr [rcx], 0 ; check dest for null
cmp byte ptr [rdx], 0 ; check src for null
; Use memmove to handle overlapping buffers for better
; compatibility with .NET Framework. Needing to handle
; overlapping buffers in cpblk is undefined by the spec.
jmp memmove ; forward to the CRT implementation
Exit_MemCpy:
ret
LEAF_END_MARKED JIT_MemCpy, _TEXT
end
|
