time_windows_arm64.s

Documentation: runtime

     1// Copyright 2018 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//go:build !faketime
     6
     7#include "go_asm.h"
     8#include "textflag.h"
     9#include "time_windows.h"
    10
    11TEXT time·now(SB),NOSPLIT,$0-24
    12	MOVD	$_INTERRUPT_TIME, R3
    13	MOVD	time_lo(R3), R0
    14	MOVD	$100, R1
    15	MUL	R1, R0
    16	MOVD	R0, mono+16(FP)
    17
    18	MOVD	$_SYSTEM_TIME, R3
    19	MOVD	time_lo(R3), R0
    20	// convert to Unix epoch (but still 100ns units)
    21	#define delta 116444736000000000
    22	SUB	$delta, R0
    23	// Convert to nSec
    24	MOVD	$100, R1
    25	MUL	R1, R0
    26
    27	// Code stolen from compiler output for:
    28	//
    29	//	var x uint64
    30	//	func f() (sec uint64, nsec uint32) { return x / 1000000000, uint32(x % 1000000000) }
    31	//
    32	LSR	$1, R0, R1
    33	MOVD	$-8543223759426509416, R2
    34	UMULH	R1, R2, R1
    35	LSR	$28, R1, R1
    36	MOVD	R1, sec+0(FP)
    37	MOVD	$1000000000, R2
    38	MSUB	R1, R0, R2, R0
    39	MOVW	R0, nsec+8(FP)
    40	RET
    41
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