rt0_freebsd_arm64.s

Documentation: runtime

     1// Copyright 2019 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 "cgo/abi_arm64.h"
     7
     8// On FreeBSD argc/argv are passed in R0, not RSP
     9TEXT _rt0_arm64_freebsd(SB),NOSPLIT|NOFRAME,$0
    10	ADD	$8, R0, R1	// argv
    11	MOVD	0(R0), R0	// argc
    12	BL	main(SB)
    13
    14// When building with -buildmode=c-shared, this symbol is called when the shared
    15// library is loaded.
    16TEXT _rt0_arm64_freebsd_lib(SB),NOSPLIT,$184
    17	// Preserve callee-save registers.
    18	SAVE_R19_TO_R28(24)
    19	SAVE_F8_TO_F15(104)
    20
    21	// Initialize g as null in case of using g later e.g. sigaction in cgo_sigaction.go
    22	MOVD	ZR, g
    23
    24	MOVD	R0, _rt0_arm64_freebsd_lib_argc<>(SB)
    25	MOVD	R1, _rt0_arm64_freebsd_lib_argv<>(SB)
    26
    27	// Synchronous initialization.
    28	MOVD	$runtime·libpreinit(SB), R4
    29	BL	(R4)
    30
    31	// Create a new thread to do the runtime initialization and return.
    32	MOVD	_cgo_sys_thread_create(SB), R4
    33	CBZ	R4, nocgo
    34	MOVD	$_rt0_arm64_freebsd_lib_go(SB), R0
    35	MOVD	$0, R1
    36	SUB	$16, RSP	// reserve 16 bytes for sp-8 where fp may be saved.
    37	BL	(R4)
    38	ADD	$16, RSP
    39	B	restore
    40
    41nocgo:
    42	MOVD	$0x800000, R0                     // stacksize = 8192KB
    43	MOVD	$_rt0_arm64_freebsd_lib_go(SB), R1
    44	MOVD	R0, 8(RSP)
    45	MOVD	R1, 16(RSP)
    46	MOVD	$runtime·newosproc0(SB),R4
    47	BL	(R4)
    48
    49restore:
    50	// Restore callee-save registers.
    51	RESTORE_R19_TO_R28(24)
    52	RESTORE_F8_TO_F15(104)
    53	RET
    54
    55TEXT _rt0_arm64_freebsd_lib_go(SB),NOSPLIT,$0
    56	MOVD	_rt0_arm64_freebsd_lib_argc<>(SB), R0
    57	MOVD	_rt0_arm64_freebsd_lib_argv<>(SB), R1
    58	MOVD	$runtime·rt0_go(SB),R4
    59	B       (R4)
    60
    61DATA _rt0_arm64_freebsd_lib_argc<>(SB)/8, $0
    62GLOBL _rt0_arm64_freebsd_lib_argc<>(SB),NOPTR, $8
    63DATA _rt0_arm64_freebsd_lib_argv<>(SB)/8, $0
    64GLOBL _rt0_arm64_freebsd_lib_argv<>(SB),NOPTR, $8
    65
    66
    67TEXT main(SB),NOSPLIT|NOFRAME,$0
    68	MOVD	$runtime·rt0_go(SB), R2
    69	BL	(R2)
    70exit:
    71	MOVD	$0, R0
    72	MOVD	$1, R8	// SYS_exit
    73	SVC
    74	B	exit
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