`define RAM_ADDRESS_BITS    23
`define RAM_BYTE_BITS       8
`define RAM_WORD_BYTES      2
`define RAM_LINE_WORDS      1

`define PDP_ADDRESS_BITS    15

`define NUM_PDPS            12

`define UART_BYTE_BITS      8

`define TAG_BITS            $clog2(`NUM_PDPS+1)

typedef bit             [`RAM_ADDRESS_BITS-1:0]                         ram_word_address_t;
typedef bit             [`RAM_ADDRESS_BITS-1:$clog2(`RAM_LINE_WORDS)]   ram_line_address_t;
typedef bit             [`RAM_BYTE_BITS-1:0]                            ram_byte_t;
typedef ram_byte_t      [`RAM_WORD_BYTES-1:0]                           ram_word_t;
typedef ram_word_t      [`RAM_LINE_WORDS-1:0]                           ram_line_t;
typedef bit             [$clog2(`RAM_WORD_BYTES):0]                     ram_word_mask_t;
typedef ram_word_mask_t [`RAM_LINE_WORDS-1:0]                           ram_line_mask_t;

typedef bit             [$clog2(`RAM_WORD_BYTES+1):0]                   ram_byte_count_t;
typedef bit             [$clog2(`RAM_LINE_WORDS+1):0]                   ram_word_count_t;

typedef bit             [`RAM_ADDRESS_BITS-1:`PDP_ADDRESS_BITS]         ram_pdp_address_space_t;

typedef bit             [`PDP_ADDRESS_BITS-1:0]                         pdp_word_address_t;
typedef bit             [`PDP_ADDRESS_BITS-1:$clog2(`RAM_LINE_WORDS)]   pdp_line_address_t;

typedef bit             [`TAG_BITS-1:0]                                 tag_t;

typedef bit             [`UART_BYTE_BITS-1:0]                           uart_byte_t;

typedef struct packed {
    ram_line_address_t  address;
    bit                 write;
    ram_line_t          data;
    ram_line_mask_t     mask;
    tag_t               tag;
} ram_command_t;

typedef struct packed {
    ram_line_address_t  address;
    ram_line_t          data;
    tag_t               tag;
} ram_read_response_t;

typedef struct packed {
    pdp_line_address_t  address;
    bit                 write;
    ram_line_t          data;
    ram_line_mask_t     mask;
} pdp_command_t;

typedef struct packed {
    pdp_line_address_t  address;
    ram_line_t          data;
} pdp_read_response_t;