github.com/ice-blockchain/go/src@v0.0.0-20240403114104-1564d284e521/runtime/cgo/asm_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  // Set the x_crosscall2_ptr C function pointer variable point to crosscall2.
     9  // It's such a pointer chain: _crosscall2_ptr -> x_crosscall2_ptr -> crosscall2
    10  // Use a local trampoline, to avoid taking the address of a dynamically exported
    11  // function.
    12  TEXT ·set_crosscall2(SB),NOSPLIT,$0-0
    13  	MOVD	_crosscall2_ptr(SB), R1
    14  	MOVD	$crosscall2_trampoline<>(SB), R2
    15  	MOVD	R2, (R1)
    16  	RET
    17  
    18  TEXT crosscall2_trampoline<>(SB),NOSPLIT,$0-0
    19  	JMP	crosscall2(SB)
    20  
    21  // Called by C code generated by cmd/cgo.
    22  // func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
    23  // Saves C callee-saved registers and calls cgocallback with three arguments.
    24  // fn is the PC of a func(a unsafe.Pointer) function.
    25  TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
    26  	/*
    27  	 * We still need to save all callee save register as before, and then
    28  	 *  push 3 args for fn (R0, R1, R3), skipping R2.
    29  	 * Also note that at procedure entry in gc world, 8(RSP) will be the
    30  	 *  first arg.
    31  	 */
    32  	SUB	$(8*24), RSP
    33  	STP	(R0, R1), (8*1)(RSP)
    34  	MOVD	R3, (8*3)(RSP)
    35  
    36  	SAVE_R19_TO_R28(8*4)
    37  	SAVE_F8_TO_F15(8*14)
    38  	STP	(R29, R30), (8*22)(RSP)
    39  
    40  
    41  	// Initialize Go ABI environment
    42  	BL	runtime·load_g(SB)
    43  	BL	runtime·cgocallback(SB)
    44  
    45  	RESTORE_R19_TO_R28(8*4)
    46  	RESTORE_F8_TO_F15(8*14)
    47  	LDP	(8*22)(RSP), (R29, R30)
    48  
    49  	ADD	$(8*24), RSP
    50  	RET