fmt.Fprintf(&buf, "const defaultGOMIPS = `%s`\n", gomips)
	fmt.Fprintf(&buf, "const defaultGOMIPS64 = `%s`\n", gomips64)
	fmt.Fprintf(&buf, "const defaultGOPPC64 = `%s`\n", goppc64)
	fmt.Fprintf(&buf, "const defaultGORISCV64 = `%s`\n", goriscv64)
	fmt.Fprintf(&buf, "const defaultGOEXPERIMENT = `%s`\n", goexperiment)
	fmt.Fprintf(&buf, "const defaultGO_EXTLINK_ENABLED = `%s`\n", goextlinkenabled)

	return int(defaultGOPPC64[len("power")] - '0')
}

func goriscv64() int {
	switch v := envOr("GORISCV64", defaultGORISCV64); v {
	case "rva20u64":
		return 20
	case "rva22u64":
		return 22
	}
	Error = fmt.Errorf("invalid GORISCV64: must be rva20u64, rva22u64")
	v := defaultGORISCV64[len("rva"):]
	i := strings.IndexFunc(v, func(r rune) bool {
		return r < '0' || r > '9'
	})