asm_arm64.s raw

   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  // 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  	// Initialize Go ABI environment
  28  	BL runtime·load_g(SB)
  29  	BL runtime·cgocallback(SB)
  30  
  31  	RESTORE_R19_TO_R28(8*4)
  32  	RESTORE_F8_TO_F15(8*14)
  33  	LDP (8*22)(RSP), (R29, R30)
  34  
  35  	ADD $(8*24), RSP
  36  	RET
  37