github.com/twelsh-aw/go/src@v0.0.0-20230516233729-a56fe86a7c81/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  // Called by C code generated by cmd/cgo.
     8  // func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
     9  // Saves C callee-saved registers and calls cgocallback with three arguments.
    10  // fn is the PC of a func(a unsafe.Pointer) function.
    11  TEXT crosscall2(SB),NOSPLIT|NOFRAME,$0
    12  	// Start with standard C stack frame layout and linkage.
    13  
    14  	// Save R6-R15 in the register save area of the calling function.
    15  	STMG	R6, R15, 48(R15)
    16  
    17  	// Allocate 96 bytes on the stack.
    18  	MOVD	$-96(R15), R15
    19  
    20  	// Save F8-F15 in our stack frame.
    21  	FMOVD	F8, 32(R15)
    22  	FMOVD	F9, 40(R15)
    23  	FMOVD	F10, 48(R15)
    24  	FMOVD	F11, 56(R15)
    25  	FMOVD	F12, 64(R15)
    26  	FMOVD	F13, 72(R15)
    27  	FMOVD	F14, 80(R15)
    28  	FMOVD	F15, 88(R15)
    29  
    30  	// Initialize Go ABI environment.
    31  	BL	runtime·load_g(SB)
    32  
    33  	MOVD	R2, 8(R15)	// fn unsafe.Pointer
    34  	MOVD	R3, 16(R15)	// a unsafe.Pointer
    35  	// Skip R4 = n uint32
    36  	MOVD	R5, 24(R15)	// ctxt uintptr
    37  	BL	runtime·cgocallback(SB)
    38  
    39  	FMOVD	32(R15), F8
    40  	FMOVD	40(R15), F9
    41  	FMOVD	48(R15), F10
    42  	FMOVD	56(R15), F11
    43  	FMOVD	64(R15), F12
    44  	FMOVD	72(R15), F13
    45  	FMOVD	80(R15), F14
    46  	FMOVD	88(R15), F15
    47  
    48  	// De-allocate stack frame.
    49  	MOVD	$96(R15), R15
    50  
    51  	// Restore R6-R15.
    52  	LMG	48(R15), R6, R15
    53  
    54  	RET
    55