github.com/dorkamotorka/go/src@v0.0.0-20230614113921-187095f0e316/runtime/cgo/asm_s390x.s (about)

     1  // Copyright 2016 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  TEXT ·set_crosscall2(SB),NOSPLIT,$0-0
    10  	MOVD	_crosscall2_ptr(SB), R1
    11  	MOVD	$crosscall2(SB), R2
    12  	MOVD	R2, (R1)
    13  	RET
    14  
    15  // Called by C code generated by cmd/cgo.
    16  // func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
    17  // Saves C callee-saved registers and calls cgocallback with three arguments.
    18  // fn is the PC of a func(a unsafe.Pointer) function.
    19  TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
    20  	// Start with standard C stack frame layout and linkage.
    21  
    22  	// Save R6-R15 in the register save area of the calling function.
    23  	STMG	R6, R15, 48(R15)
    24  
    25  	// Allocate 96 bytes on the stack.
    26  	MOVD	$-96(R15), R15
    27  
    28  	// Save F8-F15 in our stack frame.
    29  	FMOVD	F8, 32(R15)
    30  	FMOVD	F9, 40(R15)
    31  	FMOVD	F10, 48(R15)
    32  	FMOVD	F11, 56(R15)
    33  	FMOVD	F12, 64(R15)
    34  	FMOVD	F13, 72(R15)
    35  	FMOVD	F14, 80(R15)
    36  	FMOVD	F15, 88(R15)
    37  
    38  	// Initialize Go ABI environment.
    39  	BL	runtime·load_g(SB)
    40  
    41  	MOVD	R2, 8(R15)	// fn unsafe.Pointer
    42  	MOVD	R3, 16(R15)	// a unsafe.Pointer
    43  	// Skip R4 = n uint32
    44  	MOVD	R5, 24(R15)	// ctxt uintptr
    45  	BL	runtime·cgocallback(SB)
    46  
    47  	FMOVD	32(R15), F8
    48  	FMOVD	40(R15), F9
    49  	FMOVD	48(R15), F10
    50  	FMOVD	56(R15), F11
    51  	FMOVD	64(R15), F12
    52  	FMOVD	72(R15), F13
    53  	FMOVD	80(R15), F14
    54  	FMOVD	88(R15), F15
    55  
    56  	// De-allocate stack frame.
    57  	MOVD	$96(R15), R15
    58  
    59  	// Restore R6-R15.
    60  	LMG	48(R15), R6, R15
    61  
    62  	RET
    63