github.com/go-darwin/sys@v0.0.0-20220510002607-68fd01f054ca/crosscall2_arm64.s (about)

     1  // Copyright 2015 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  #include "abi_arm64.h"
     7  
     8  // crosscall2 called by C code generated by cmd/cgo.
     9  // func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
    10  // Saves C callee-saved registers and calls cgocallback with three arguments.
    11  // fn is the PC of a func(a unsafe.Pointer) function.
    12  TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
    13  	/*
    14  	 * We still need to save all callee save register as before, and then
    15  	 *  push 3 args for fn (R0, R1, R3), skipping R2.
    16  	 * Also note that at procedure entry in gc world, 8(RSP) will be the
    17  	 *  first arg.
    18  	 */
    19  	SUB	$(8*24), RSP
    20  	STP	(R0, R1), (8*1)(RSP)
    21  	MOVD	R3, (8*3)(RSP)
    22  
    23  	SAVE_R19_TO_R28(8*4)
    24  	SAVE_F8_TO_F15(8*14)
    25  	STP	(R29, R30), (8*22)(RSP)
    26  
    27  
    28  	// Initialize Go ABI environment
    29  	BL	runtime·load_g(SB)
    30  	BL	runtime·cgocallback(SB)
    31  
    32  	RESTORE_R19_TO_R28(8*4)
    33  	RESTORE_F8_TO_F15(8*14)
    34  	LDP	(8*22)(RSP), (R29, R30)
    35  
    36  	ADD	$(8*24), RSP
    37  	RET