github.com/aloncn/graphics-go@v0.0.1/src/runtime/cgo/asm_arm.s (about)

     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  /*
     8   * void crosscall2(void (*fn)(void*, int32), void*, int32)
     9   * Save registers and call fn with two arguments.
    10   */
    11  TEXT crosscall2(SB),NOSPLIT,$-4
    12  	/* 
    13  	 * We still need to save all callee save register as before, and then
    14  	 *  push 2 args for fn (R1 and R2).
    15  	 * Also note that at procedure entry in gc world, 4(R13) will be the
    16  	 *  first arg, so we must push another dummy reg (R0) for 0(R13).
    17  	 *  Additionally, runtime·load_g will clobber R0, so we need to save R0
    18  	 *  nevertheless.
    19  	 */
    20  	MOVM.WP	[R0, R1, R2, R4, R5, R6, R7, R8, R9, g, R11, R12, R14], (R13)
    21  	BL	runtime·load_g(SB)
    22  	MOVW	R15, R14 // R15 is PC.
    23  	MOVW	0(R13), R15
    24  	MOVM.IAW	(R13), [R0, R1, R2, R4, R5, R6, R7, R8, R9, g, R11, R12, R15]