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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build !faketime
#include "go_asm.h"
#include "textflag.h"
#include "time_windows.h"
TEXT time·now(SB),NOSPLIT,$0-20
CMPB runtime·useQPCTime(SB), $0
JNE useQPC
loop:
MOVL (_INTERRUPT_TIME+time_hi1), AX
MOVL (_INTERRUPT_TIME+time_lo), CX
MOVL (_INTERRUPT_TIME+time_hi2), DI
CMPL AX, DI
JNE loop
// w = DI:CX
// multiply by 100
MOVL $100, AX
MULL CX
IMULL $100, DI
ADDL DI, DX
// w*100 = DX:AX
MOVL AX, mono+12(FP)
MOVL DX, mono+16(FP)
wall:
MOVL (_SYSTEM_TIME+time_hi1), CX
MOVL (_SYSTEM_TIME+time_lo), AX
MOVL (_SYSTEM_TIME+time_hi2), DX
CMPL CX, DX
JNE wall
// w = DX:AX
// convert to Unix epoch (but still 100ns units)
#define delta 116444736000000000
SUBL $(delta & 0xFFFFFFFF), AX
SBBL $(delta >> 32), DX
// nano/100 = DX:AX
// split into two decimal halves by div 1e9.
// (decimal point is two spots over from correct place,
// but we avoid overflow in the high word.)
MOVL $1000000000, CX
DIVL CX
MOVL AX, DI
MOVL DX, SI
// DI = nano/100/1e9 = nano/1e11 = sec/100, DX = SI = nano/100%1e9
// split DX into seconds and nanoseconds by div 1e7 magic multiply.
MOVL DX, AX
MOVL $1801439851, CX
MULL CX
SHRL $22, DX
MOVL DX, BX
IMULL $10000000, DX
MOVL SI, CX
SUBL DX, CX
// DI = sec/100 (still)
// BX = (nano/100%1e9)/1e7 = (nano/1e9)%100 = sec%100
// CX = (nano/100%1e9)%1e7 = (nano%1e9)/100 = nsec/100
// store nsec for return
IMULL $100, CX
MOVL CX, nsec+8(FP)
// DI = sec/100 (still)
// BX = sec%100
// construct DX:AX = 64-bit sec and store for return
MOVL $0, DX
MOVL $100, AX
MULL DI
ADDL BX, AX
ADCL $0, DX
MOVL AX, sec+0(FP)
MOVL DX, sec+4(FP)
RET
useQPC:
JMP runtime·nowQPC(SB)
RET
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