c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		return t.lookupValue(uint32(i), c1), 2
	case c0 < 0xF0: // 3-byte UTF-8
		if len(s) < 3 {
			return 0, 0
		}
		i := bidiIndex[c0]
		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		o := uint32(i)<<6 + uint32(c1)
		i = bidiIndex[o]
		c2 := s[2]

		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		return t.lookupValue(uint32(i), c1), 2
	case c0 < 0xF0: // 3-byte UTF-8
		if len(s) < 3 {
			return 0, 0
		}
		i := caseIndex[c0]
		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		o := uint32(i)<<6 + uint32(c1)
		i = caseIndex[o]
		c2 := s[2]

		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		return t.lookupValue(uint32(i), c1), 2
	case c0 < 0xF0: // 3-byte UTF-8
		if len(s) < 3 {
			return 0, 0
		}
		i := bidiIndex[c0]
		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		o := uint32(i)<<6 + uint32(c1)
		i = bidiIndex[o]
		c2 := s[2]

		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		return t.lookupValue(uint32(i), c1), 2
	case c0 < 0xF0: // 3-byte UTF-8
		if len(s) < 3 {
			return 0, 0
		}
		i := caseIndex[c0]
		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		o := uint32(i)<<6 + uint32(c1)
		i = caseIndex[o]
		c2 := s[2]

		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		return t.lookupValue(uint32(i), c1), 2
	case c0 < 0xF0: // 3-byte UTF-8
		if len(s) < 3 {
			return 0, 0
		}
		i := bidiIndex[c0]
		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		o := uint32(i)<<6 + uint32(c1)
		i = bidiIndex[o]
		c2 := s[2]

		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		return t.lookupValue(uint32(i), c1), 2
	case c0 < 0xF0: // 3-byte UTF-8
		if len(s) < 3 {
			return 0, 0
		}
		i := bidiIndex[c0]
		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		o := uint32(i)<<6 + uint32(c1)
		i = bidiIndex[o]
		c2 := s[2]

		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		return t.lookupValue(uint32(i), c1), 2
	case c0 < 0xF0: // 3-byte UTF-8
		if len(s) < 3 {
			return 0, 0
		}
		i := bidiIndex[c0]
		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		o := uint32(i)<<6 + uint32(c1)
		i = bidiIndex[o]
		c2 := s[2]

		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		return t.lookupValue(uint32(i), c1), 2
	case c0 < 0xF0: // 3-byte UTF-8
		if len(s) < 3 {
			return 0, 0
		}
		i := caseIndex[c0]
		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		o := uint32(i)<<6 + uint32(c1)
		i = caseIndex[o]
		c2 := s[2]

		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		return t.lookupValue(uint32(i), c1), 2
	case c0 < 0xF0: // 3-byte UTF-8
		if len(s) < 3 {
			return 0, 0
		}
		i := bidiIndex[c0]
		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		o := uint32(i)<<6 + uint32(c1)
		i = bidiIndex[o]
		c2 := s[2]

	gp := getg()

	setMNoWB(&gp.m.curg.m, nil)
	setGNoWB(&gp.m.curg, nil)
}

func parkunlock_c(gp *g, lock unsafe.Pointer) bool {
	unlock((*mutex)(lock))
	return true
}

// park continuation on g0.
func park_m(gp *g) {
	mp := getg().m

	trace := traceAcquire()

	if trace.ok() {
		// Trace the event before the transition. It may take a