1// Copyright 2025 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5#include "go_asm.h"
6#include "textflag.h"
7
8TEXT ·StdCall<ABIInternal>(SB),NOSPLIT,$0
9 JMP ·asmstdcall(SB)
10
11TEXT ·asmstdcall(SB),NOSPLIT,$0
12 MOVL fn+0(FP), BX
13 MOVL SP, BP // save stack pointer
14
15 // SetLastError(0).
16 MOVL $0, 0x34(FS)
17
18 MOVL StdCallInfo_N(BX), CX
19
20 // Fast version, do not store args on the stack.
21 CMPL CX, $0
22 JE docall
23
24 // Copy args to the stack.
25 MOVL CX, AX
26 SALL $2, AX
27 SUBL AX, SP // room for args
28 MOVL SP, DI
29 MOVL StdCallInfo_Args(BX), SI
30 CLD
31 REP; MOVSL
32
33docall:
34 // Call stdcall or cdecl function.
35 // DI SI BP BX are preserved, SP is not
36 CALL StdCallInfo_Fn(BX)
37 MOVL BP, SP
38
39 // Return result.
40 MOVL fn+0(FP), BX
41 MOVL AX, StdCallInfo_R1(BX)
42 MOVL DX, StdCallInfo_R2(BX)
43
44 // GetLastError().
45 MOVL 0x34(FS), AX
46 MOVL AX, StdCallInfo_Err(BX)
47
48 RET
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