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Editing: time_linux_amd64.s
// Copyright 2021 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 "go_tls.h" #include "textflag.h" #define SYS_clock_gettime 228 // func time.now() (sec int64, nsec int32, mono int64) TEXT time·now<ABIInternal>(SB),NOSPLIT,$16-24 MOVQ SP, R12 // Save old SP; R12 unchanged by C code. MOVQ g_m(R14), BX // BX unchanged by C code. // Set vdsoPC and vdsoSP for SIGPROF traceback. // Save the old values on stack and restore them on exit, // so this function is reentrant. MOVQ m_vdsoPC(BX), CX MOVQ m_vdsoSP(BX), DX MOVQ CX, 0(SP) MOVQ DX, 8(SP) LEAQ sec+0(FP), DX MOVQ -8(DX), CX // Sets CX to function return address. MOVQ CX, m_vdsoPC(BX) MOVQ DX, m_vdsoSP(BX) CMPQ R14, m_curg(BX) // Only switch if on curg. JNE noswitch MOVQ m_g0(BX), DX MOVQ (g_sched+gobuf_sp)(DX), SP // Set SP to g0 stack noswitch: SUBQ $32, SP // Space for two time results ANDQ $~15, SP // Align for C code MOVL $0, DI // CLOCK_REALTIME LEAQ 16(SP), SI MOVQ runtime·vdsoClockgettimeSym(SB), AX CMPQ AX, $0 JEQ fallback CALL AX MOVL $1, DI // CLOCK_MONOTONIC LEAQ 0(SP), SI MOVQ runtime·vdsoClockgettimeSym(SB), AX CALL AX ret: MOVQ 16(SP), AX // realtime sec MOVQ 24(SP), DI // realtime nsec (moved to BX below) MOVQ 0(SP), CX // monotonic sec IMULQ $1000000000, CX MOVQ 8(SP), DX // monotonic nsec MOVQ R12, SP // Restore real SP // Restore vdsoPC, vdsoSP // We don't worry about being signaled between the two stores. // If we are not in a signal handler, we'll restore vdsoSP to 0, // and no one will care about vdsoPC. If we are in a signal handler, // we cannot receive another signal. MOVQ 8(SP), SI MOVQ SI, m_vdsoSP(BX) MOVQ 0(SP), SI MOVQ SI, m_vdsoPC(BX) // set result registers; AX is already correct MOVQ DI, BX ADDQ DX, CX RET fallback: MOVQ $SYS_clock_gettime, AX SYSCALL MOVL $1, DI // CLOCK_MONOTONIC LEAQ 0(SP), SI MOVQ $SYS_clock_gettime, AX SYSCALL JMP ret
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