{reg: [
    {bits: 7, name: 43,       attr: 'Opcode: Custom-1'},
    {bits: 5, name: 'rd',     attr: 'Destination'},
    {bits: 3, name: 'funct3', type: 1},
    {bits: 5, name: 'rs1',    attr: 'Source 1'},
    {bits: 5, name: 'rs2',    attr: 'Source 2'},
    {bits: 2, name: 4,        attr: '-'},
    {bits: 5, name: 'rs3',    attr: 'Source 3'}
]}