// it tries to collect a traceback into sigprofCallers.
// sigprofCallersUse is set to non-zero while sigprofCallers holds a traceback.
var sigprofCallers cgoCallers
var sigprofCallersUse uint32

// sigprofNonGo is called if we receive a SIGPROF signal on a non-Go thread,
// and the signal handler collected a stack trace in sigprofCallers.
// When this is called, sigprofCallersUse will be non-zero.
// g is nil, and what we can do is very limited.

sigtramp:
	JMP	runtime·sigtramp(SB)

sigtrampnog:
	// Signal arrived on a non-Go thread. If this is SIGPROF, get a
	// stack trace.
	CMPL	DI, $27 // 27 == SIGPROF
	JNZ	sigtramp

	// Lock sigprofCallersUse.
	MOVL	$0, AX
	MOVL	$1, CX
	MOVQ	$runtime·sigprofCallersUse(SB), R11
	LOCK
	CMPXCHGL	CX, 0(R11)
	JNZ	sigtramp  // Skip stack trace if already locked.

sigtramp:
	JMP	runtime·sigtramp(SB)

sigtrampnog:
	// Signal arrived on a non-Go thread. If this is SIGPROF, get a
	// stack trace.
	CMPL	DI, $27 // 27 == SIGPROF
	JNZ	sigtramp

	// Lock sigprofCallersUse.
	MOVL	$0, AX
	MOVL	$1, CX
	MOVQ	$runtime·sigprofCallersUse(SB), R11
	LOCK
	CMPXCHGL	CX, 0(R11)
	JNZ	sigtramp  // Skip stack trace if already locked.

	JMP	runtime·sigtramp(SB)

sigtrampnog:
	// Signal arrived on a non-Go thread. If this is SIGPROF, get a
	// stack trace.
	CMPW	R3, $27 // 27 == SIGPROF
	BNE	sigtramp

	// Lock sigprofCallersUse (cas from 0 to 1).
	MOVW	$1, R7
	MOVD	$runtime·sigprofCallersUse(SB), R8
	SYNC
	LWAR    (R8), R6
	CMPW    $0, R6
	BNE     sigtramp
	STWCCC  R7, (R8)
	BNE     -4(PC)
	ISYNC

	MOVD	R12, g
	B	runtime·sigtramp(SB)

sigtrampnog:
	// Signal arrived on a non-Go thread. If this is SIGPROF, get a
	// stack trace.
	CMPW	$27, R0 // 27 == SIGPROF
	BNE	sigtramp

	// Lock sigprofCallersUse (cas from 0 to 1).
	MOVW	$1, R7
	MOVD	$runtime·sigprofCallersUse(SB), R8
load_store_loop:
	LDAXRW	(R8), R9
	CBNZW	R9, sigtramp // Skip stack trace if already locked.
	STLXRW	R7, (R8), R9

sigtramp:
	JMP	runtime·sigtramp(SB)

sigtrampnog:
	// Signal arrived on a non-Go thread. If this is SIGPROF, get a
	// stack trace.
	CMPL	DI, $27 // 27 == SIGPROF
	JNZ	sigtramp

	// Lock sigprofCallersUse.
	MOVL	$0, AX
	MOVL	$1, CX
	MOVQ	$runtime·sigprofCallersUse(SB), R11
	LOCK
	CMPXCHGL	CX, 0(R11)
	JNZ	sigtramp  // Skip stack trace if already locked.