// exception record and context pointers.
// DX is the kind of sigtramp function.
// Return value of sigtrampgo is stored in AX.
TEXT sigtramp<>(SB),NOSPLIT,$0-0
	// Switch from the host ABI to the Go ABI.
	PUSH_REGS_HOST_TO_ABI0()

	// Set up ABIInternal environment: cleared X15 and R14.
	// R14 is cleared in case there's a non-zero value in there
	// if called from a non-go thread.
	XORPS	X15, X15
	XORQ	R14, R14

// Saves C callee-saved registers and calls cgocallback with three arguments.
// fn is the PC of a func(a unsafe.Pointer) function.
// This signature is known to SWIG, so we can't change it.
TEXT crosscall2(SB),NOSPLIT,$0-0
	PUSH_REGS_HOST_TO_ABI0()

	// Make room for arguments to cgocallback.
	ADJSP	$0x18
#ifndef GOOS_windows
	MOVQ	DI, 0x0(SP)	/* fn */
	MOVQ	SI, 0x8(SP)	/* arg */
	// Skip n in DX.
	MOVQ	CX, 0x10(SP)	/* ctxt */
#else

// a signal is received. It just redirects to the Go function sigtrampgo.
// Called using C ABI.
TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME|NOFRAME,$0
	// Transition from C ABI to Go ABI.
	PUSH_REGS_HOST_TO_ABI0()

	// Set up ABIInternal environment: g in R14, cleared X15.
	get_tls(R12)
	MOVQ	g(R12), R14
	PXOR	X15, X15

	// Reserve space for spill slots.
	NOP	SP		// disable vet stack checking

	MOVQ	g(RARG0), RARG0
	MOVQ	g_m(RARG0), RARG0
	MOVQ	m_p(RARG0), RARG0
	MOVQ	p_raceprocctx(RARG0), RARG0
	MOVQ	RARG0, (RARG1)
	RET

rest:
	// Transition from C ABI to Go ABI.
	PUSH_REGS_HOST_TO_ABI0()
	// Set g = g0.
	get_tls(R12)
	MOVQ	g(R12), R14
	MOVQ	g_m(R14), R13
	MOVQ	m_g0(R13), R15
	CMPQ	R13, R15
	JEQ	noswitch	// branch if already on g0
	MOVQ	R15, g(R12)	// g = m->g0

// We expect argc and argv to be passed in the usual C ABI registers
// DI and SI.
TEXT _rt0_amd64_lib(SB),NOSPLIT|NOFRAME,$0
	// Transition from C ABI to Go ABI.
	PUSH_REGS_HOST_TO_ABI0()

	MOVQ	DI, _rt0_amd64_lib_argc<>(SB)
	MOVQ	SI, _rt0_amd64_lib_argv<>(SB)

	// Synchronous initialization.
	CALL	runtime·libpreinit(SB)

	// Create a new thread to finish Go runtime initialization.