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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.
.586
.model flat
option casemap:none
.code
include AsmMacros.inc
EXTERN @GetClasslibCCtorCheck@4 : PROC
EXTERN _memcpy : PROC
EXTERN _memcpyGCRefs : PROC
EXTERN _memcpyGCRefsWithWriteBarrier : PROC
EXTERN _memcpyAnyWithWriteBarrier : PROC
;;
;; Checks whether the static class constructor for the type indicated by the context structure has been
;; executed yet. If not the classlib is called via their CheckStaticClassConstruction callback which will
;; execute the cctor and update the context to record this fact.
;;
;; Input:
;; eax : Address of StaticClassConstructionContext structure
;;
;; Output:
;; All volatile registers and the condition codes may be trashed.
;;
FASTCALL_FUNC RhpCheckCctor, 4
;; Check the m_initialized field of the context. The cctor has been run only if this equals 1 (the
;; initial state is 0 and the remaining values are reserved for classlib use). This check is
;; unsynchronized; if we go down the slow path and call the classlib then it is responsible for
;; synchronizing with other threads and re-checking the value.
cmp dword ptr [eax + OFFSETOF__StaticClassConstructionContext__m_initialized], 1
jne RhpCheckCctor__SlowPath
ret
RhpCheckCctor__SlowPath:
mov edx, eax ; RhpCheckCctor2 takes the static class construction context pointer in the edx register
jmp @RhpCheckCctor2@4
FASTCALL_ENDFUNC
;;
;; Checks whether the static class constructor for the type indicated by the context structure has been
;; executed yet. If not the classlib is called via their CheckStaticClassConstruction callback which will
;; execute the cctor and update the context to record this fact.
;;
;; Input:
;; eax : Value that must be preserved in this register across the cctor check.
;; edx : Address of StaticClassConstructionContext structure
;;
;; Output:
;; All volatile registers other than eax may be trashed and the condition codes may also be trashed.
;;
FASTCALL_FUNC RhpCheckCctor2, 4
;; Check the m_initialized field of the context. The cctor has been run only if this equals 1 (the
;; initial state is 0 and the remaining values are reserved for classlib use). This check is
;; unsynchronized; if we go down the slow path and call the classlib then it is responsible for
;; synchronizing with other threads and re-checking the value.
cmp dword ptr [edx + OFFSETOF__StaticClassConstructionContext__m_initialized], 1
jne RhpCheckCctor2__SlowPath
ret
;; Input:
;; eax : Value that must be preserved in this register across the cctor check.
;; edx : Address of StaticClassConstructionContext structure
;;
;; Output:
;; All volatile registers other than eax may be trashed and the condition codes may also be trashed.
;;
RhpCheckCctor2__SlowPath:
;; Call a C++ helper to retrieve the address of the classlib callback. We need to preserve the context
;; structure address in eax since it's needed for the actual call.
push ebx
push esi
mov ebx, edx ; save cctor context pointer
mov esi, eax ; save preserved return value
;; The caller's return address is passed as the argument to the helper; it's an address in the module
;; and is used by the helper to locate the classlib.
mov ecx, [esp + 8] ; + 8 to skip past the saved ebx and esi
call @GetClasslibCCtorCheck@4
;; Eax now contains the address of the classlib method to call. The single argument is the context
;; structure address currently in ebx. Clean up and tail call to the classlib callback so we're not on
;; the stack should a GC occur (so we don't need to worry about transition frames).
mov edx, ebx
mov ecx, esi
pop esi
pop ebx
;; Tail-call the classlib cctor check function. Note that the incoming eax value is moved to ecx
;; and the classlib cctor check function is required to return that value, so that eax is preserved
;; across a RhpCheckCctor call.
jmp eax
FASTCALL_ENDFUNC
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; void* __cdecl RhpCopyMultibyteNoGCRefs(void*, void*, size_t)
;;
;; The purpose of this wrapper is to hoist the potential null reference exceptions of copying memory up to a place where
;; the stack unwinder and exception dispatch can properly transform the exception into a managed exception and dispatch
;; it to managed code.
;;
_RhpCopyMultibyteNoGCRefs PROC PUBLIC
; #locals, num_params, prolog bytes, #regs saved, use ebp, frame type (0 == FRAME_FPO)
.FPO( 0, 3, 0, 0, 0, 0)
; [esp + 0] return address
; [esp + 4] dest
; [esp + 8] src
; [esp + c] count
cmp dword ptr [esp + 0Ch], 0 ; check for a zero-length copy
jz NothingToCopy
mov ecx, [esp + 4] ; ecx <- dest
mov edx, [esp + 8] ; edx <- src
; Now check the dest and src pointers. If they AV, the EH subsystem will recognize the address of the AV,
; unwind the frame, and fixup the stack to make it look like the (managed) caller AV'ed, which will be
; translated to a managed exception as usual.
ALTERNATE_ENTRY RhpCopyMultibyteNoGCRefsDestAVLocation
cmp byte ptr [ecx], 0
ALTERNATE_ENTRY RhpCopyMultibyteNoGCRefsSrcAVLocation
cmp byte ptr [edx], 0
; tail-call to plain-old-memcpy
jmp _memcpy
NothingToCopy:
mov eax, [esp + 4] ; return dest
ret
_RhpCopyMultibyteNoGCRefs ENDP
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; void* __cdecl RhpCopyMultibyte(void*, void*, size_t)
;;
;; The purpose of this wrapper is to hoist the potential null reference exceptions of copying memory up to a place where
;; the stack unwinder and exception dispatch can properly transform the exception into a managed exception and dispatch
;; it to managed code.
;;
_RhpCopyMultibyte PROC PUBLIC
; #locals, num_params, prolog bytes, #regs saved, use ebp, frame type (0 == FRAME_FPO)
.FPO( 0, 3, 0, 0, 0, 0)
; [esp + 0] return address
; [esp + 4] dest
; [esp + 8] src
; [esp + c] count
cmp dword ptr [esp + 0Ch], 0 ; check for a zero-length copy
jz NothingToCopy
mov ecx, [esp + 4] ; ecx <- dest
mov edx, [esp + 8] ; edx <- src
; Now check the dest and src pointers. If they AV, the EH subsystem will recognize the address of the AV,
; unwind the frame, and fixup the stack to make it look like the (managed) caller AV'ed, which will be
; translated to a managed exception as usual.
ALTERNATE_ENTRY RhpCopyMultibyteDestAVLocation
cmp byte ptr [ecx], 0
ALTERNATE_ENTRY RhpCopyMultibyteSrcAVLocation
cmp byte ptr [edx], 0
; tail-call to the GC-safe memcpy implementation
; NOTE: this is also a __cdecl function
jmp _memcpyGCRefs
NothingToCopy:
mov eax, [esp + 4] ; return dest
ret
_RhpCopyMultibyte ENDP
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; void* __cdecl RhpCopyMultibyteWithWriteBarrier(void*, void*, size_t)
;;
;; The purpose of this wrapper is to hoist the potential null reference exceptions of copying memory up to a place where
;; the stack unwinder and exception dispatch can properly transform the exception into a managed exception and dispatch
;; it to managed code.
;; Runs a card table update via RhpBulkWriteBarrier after the copy
;;
_RhpCopyMultibyteWithWriteBarrier PROC PUBLIC
; #locals, num_params, prolog bytes, #regs saved, use ebp, frame type (0 == FRAME_FPO)
.FPO( 0, 3, 0, 0, 0, 0)
; [esp + 0] return address
; [esp + 4] dest
; [esp + 8] src
; [esp + c] count
cmp dword ptr [esp + 0Ch], 0 ; check for a zero-length copy
jz NothingToCopy
mov ecx, [esp + 4] ; ecx <- dest
mov edx, [esp + 8] ; edx <- src
; Now check the dest and src pointers. If they AV, the EH subsystem will recognize the address of the AV,
; unwind the frame, and fixup the stack to make it look like the (managed) caller AV'ed, which will be
; translated to a managed exception as usual.
ALTERNATE_ENTRY RhpCopyMultibyteWithWriteBarrierDestAVLocation
cmp byte ptr [ecx], 0
ALTERNATE_ENTRY RhpCopyMultibyteWithWriteBarrierSrcAVLocation
cmp byte ptr [edx], 0
; tail-call to the GC-safe memcpy implementation
; NOTE: this is also a __cdecl function
jmp _memcpyGCRefsWithWriteBarrier
NothingToCopy:
mov eax, [esp + 4] ; return dest
ret
_RhpCopyMultibyteWithWriteBarrier ENDP
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; void* __cdecl RhpCopyAnyWithWriteBarrier(void*, void*, size_t)
;;
;; The purpose of this wrapper is to hoist the potential null reference exceptions of copying memory up to a place where
;; the stack unwinder and exception dispatch can properly transform the exception into a managed exception and dispatch
;; it to managed code.
;; Runs a card table update via RhpBulkWriteBarrier after the copy if it contained GC pointers
;;
_RhpCopyAnyWithWriteBarrier PROC PUBLIC
; #locals, num_params, prolog bytes, #regs saved, use ebp, frame type (0 == FRAME_FPO)
.FPO( 0, 3, 0, 0, 0, 0)
; [esp + 0] return address
; [esp + 4] dest
; [esp + 8] src
; [esp + c] count
cmp dword ptr [esp + 0Ch], 0 ; check for a zero-length copy
jz NothingToCopy
mov ecx, [esp + 4] ; ecx <- dest
mov edx, [esp + 8] ; edx <- src
; Now check the dest and src pointers. If they AV, the EH subsystem will recognize the address of the AV,
; unwind the frame, and fixup the stack to make it look like the (managed) caller AV'ed, which will be
; translated to a managed exception as usual.
ALTERNATE_ENTRY RhpCopyAnyWithWriteBarrierDestAVLocation
cmp byte ptr [ecx], 0
ALTERNATE_ENTRY RhpCopyAnyWithWriteBarrierSrcAVLocation
cmp byte ptr [edx], 0
; tail-call to the GC-safe memcpy implementation
; NOTE: this is also a __cdecl function
jmp _memcpyAnyWithWriteBarrier
NothingToCopy:
mov eax, [esp + 4] ; return dest
ret
_RhpCopyAnyWithWriteBarrier ENDP
end
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