1// Copyright 2012 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 "textflag.h"
6
7// Set the x_crosscall2_ptr C function pointer variable point to crosscall2.
8// It's such a pointer chain: _crosscall2_ptr -> x_crosscall2_ptr -> crosscall2
9// Use a local trampoline, to avoid taking the address of a dynamically exported
10// function.
11TEXT ·set_crosscall2(SB),NOSPLIT,$0-0
12	MOVW	_crosscall2_ptr(SB), R1
13	MOVW	$crosscall2_trampoline<>(SB), R2
14	MOVW	R2, (R1)
15	RET
16
17TEXT crosscall2_trampoline<>(SB),NOSPLIT,$0-0
18	JMP	crosscall2(SB)
19
20// Called by C code generated by cmd/cgo.
21// func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
22// Saves C callee-saved registers and calls cgocallback with three arguments.
23// fn is the PC of a func(a unsafe.Pointer) function.
24TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
25	SUB	$(8*9), R13 // Reserve space for the floating point registers.
26	// The C arguments arrive in R0, R1, R2, and R3. We want to
27	// pass R0, R1, and R3 to Go, so we push those on the stack.
28	// Also, save C callee-save registers R4-R12.
29	MOVM.WP	[R0, R1, R3, R4, R5, R6, R7, R8, R9, g, R11, R12], (R13)
30	// Finally, save the link register R14. This also puts the
31	// arguments we pushed for cgocallback where they need to be,
32	// starting at 4(R13).
33	MOVW.W	R14, -4(R13)
34
35	// Skip floating point registers if goarmsoftfp!=0.
36	MOVB    runtime·goarmsoftfp(SB), R11
37	CMP     $0, R11
38	BNE     skipfpsave
39	MOVD	F8, (13*4+8*1)(R13)
40	MOVD	F9, (13*4+8*2)(R13)
41	MOVD	F10, (13*4+8*3)(R13)
42	MOVD	F11, (13*4+8*4)(R13)
43	MOVD	F12, (13*4+8*5)(R13)
44	MOVD	F13, (13*4+8*6)(R13)
45	MOVD	F14, (13*4+8*7)(R13)
46	MOVD	F15, (13*4+8*8)(R13)
47
48skipfpsave:
49	BL	runtime·load_g(SB)
50	// We set up the arguments to cgocallback when saving registers above.
51	BL	runtime·cgocallback(SB)
52
53	MOVB    runtime·goarmsoftfp(SB), R11
54	CMP     $0, R11
55	BNE     skipfprest
56	MOVD	(13*4+8*1)(R13), F8
57	MOVD	(13*4+8*2)(R13), F9
58	MOVD	(13*4+8*3)(R13), F10
59	MOVD	(13*4+8*4)(R13), F11
60	MOVD	(13*4+8*5)(R13), F12
61	MOVD	(13*4+8*6)(R13), F13
62	MOVD	(13*4+8*7)(R13), F14
63	MOVD	(13*4+8*8)(R13), F15
64
65skipfprest:
66	MOVW.P	4(R13), R14
67	MOVM.IAW	(R13), [R0, R1, R3, R4, R5, R6, R7, R8, R9, g, R11, R12]
68	ADD	$(8*9), R13
69	MOVW	R14, R15
70