; 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.

; ==++==
;

;
; ==--==

include AsmMacros.inc
include AsmConstants.inc

extern GenericPInvokeCalliStubWorker:proc
extern VarargPInvokeStubWorker:proc

;
; in:
; PINVOKE_CALLI_TARGET_REGISTER (r10) = unmanaged target
; PINVOKE_CALLI_SIGTOKEN_REGNUM (r11) = sig token       
;
; out:
; METHODDESC_REGISTER           (r10) = unmanaged target
;
LEAF_ENTRY GenericPInvokeCalliHelper, _TEXT
        
        ;
        ; check for existing IL stub
        ;
        mov             rax, [PINVOKE_CALLI_SIGTOKEN_REGISTER + OFFSETOF__VASigCookie__pNDirectILStub]
        test            rax, rax
        jz              GenericPInvokeCalliGenILStub

        ;
        ; We need to distinguish between a MethodDesc* and an unmanaged target in PInvokeStubForHost().  
        ; The way we do this is to shift the managed target to the left by one bit and then set the 
        ; least significant bit to 1.  This works because MethodDesc* are always 8-byte aligned.
        ;
        shl             PINVOKE_CALLI_TARGET_REGISTER, 1
        or              PINVOKE_CALLI_TARGET_REGISTER, 1

        ;
        ; jump to existing IL stub
        ;
        jmp             rax

LEAF_END GenericPInvokeCalliHelper, _TEXT

NESTED_ENTRY GenericPInvokeCalliGenILStub, _TEXT
        
        PROLOG_WITH_TRANSITION_BLOCK

        ;
        ; save target
        ;
        mov             r12, METHODDESC_REGISTER
        mov             r13, PINVOKE_CALLI_SIGTOKEN_REGISTER

        ;
        ; GenericPInvokeCalliStubWorker(TransitionBlock * pTransitionBlock, VASigCookie * pVASigCookie, PCODE pUnmanagedTarget)
        ;
        lea             rcx, [rsp + __PWTB_TransitionBlock]     ; pTransitionBlock*
        mov             rdx, PINVOKE_CALLI_SIGTOKEN_REGISTER    ; pVASigCookie
        mov             r8, METHODDESC_REGISTER                 ; pUnmanagedTarget
        call            GenericPInvokeCalliStubWorker

        ;
        ; restore target
        ;
        mov             METHODDESC_REGISTER, r12
        mov             PINVOKE_CALLI_SIGTOKEN_REGISTER, r13

        EPILOG_WITH_TRANSITION_BLOCK_TAILCALL
        jmp             GenericPInvokeCalliHelper

NESTED_END GenericPInvokeCalliGenILStub, _TEXT

LEAF_ENTRY VarargPInvokeStub, _TEXT
        mov             PINVOKE_CALLI_SIGTOKEN_REGISTER, rcx
        jmp             VarargPInvokeStubHelper
LEAF_END VarargPInvokeStub, _TEXT
        
LEAF_ENTRY VarargPInvokeStub_RetBuffArg, _TEXT
        mov             PINVOKE_CALLI_SIGTOKEN_REGISTER, rdx
        jmp             VarargPInvokeStubHelper
LEAF_END VarargPInvokeStub_RetBuffArg, _TEXT

LEAF_ENTRY VarargPInvokeStubHelper, _TEXT
        ;
        ; check for existing IL stub
        ;
        mov             rax, [PINVOKE_CALLI_SIGTOKEN_REGISTER + OFFSETOF__VASigCookie__pNDirectILStub]
        test            rax, rax
        jz              VarargPInvokeGenILStub

        ;
        ; jump to existing IL stub
        ;
        jmp             rax
        
LEAF_END VarargPInvokeStubHelper, _TEXT

;
; IN: METHODDESC_REGISTER (R10) stub secret param
;     PINVOKE_CALLI_SIGTOKEN_REGISTER (R11) VASigCookie*
;
; ASSUMES: we already checked for an existing stub to use
;
NESTED_ENTRY VarargPInvokeGenILStub, _TEXT

        PROLOG_WITH_TRANSITION_BLOCK 

        ;
        ; save target
        ;
        mov             r12, METHODDESC_REGISTER
        mov             r13, PINVOKE_CALLI_SIGTOKEN_REGISTER

        ;
        ; VarargPInvokeStubWorker(TransitionBlock * pTransitionBlock, VASigCookie *pVASigCookie, MethodDesc *pMD)
        ;
        lea             rcx, [rsp + __PWTB_TransitionBlock]     ; pTransitionBlock*
        mov             rdx, PINVOKE_CALLI_SIGTOKEN_REGISTER    ; pVASigCookie
        mov             r8, METHODDESC_REGISTER                 ; pMD
        call            VarargPInvokeStubWorker

        ;
        ; restore target
        ;
        mov             METHODDESC_REGISTER, r12
        mov             PINVOKE_CALLI_SIGTOKEN_REGISTER, r13

        EPILOG_WITH_TRANSITION_BLOCK_TAILCALL
        jmp             VarargPInvokeStubHelper

NESTED_END VarargPInvokeGenILStub, _TEXT

        end