// set 64Drive interface constants.

// NOTE: although STATUSes are marked as halfwords,
//       you should use lw/sw to interact with them.

constant CI_BASE($B800)
constant CI_BASE_EXTENDED($BF80)

constant CI_GENERAL_BUFFER($0000)       // 512 bytes

constant CI_STATUS($0200)               // halfword
constant CI_COMMAND($0208)              // word
constant CI_LBA($0210)                  // word
constant CI_LENGTH($0218)               // word
constant CI_RESULT($0220)               // word

constant CI_SDRAM_SIZE($02E8)           // word
constant CI_HW_MAGIC($02EC)             // word ("UDEV")
constant CI_HW_VARIANT($02F0)           // word
constant CI_PERSISTENT($02F4)           // word (RESERVED)
constant CI_BUTTON_STATUS($02F8)        // halfword (needs debouncing)
constant CI_UPGRADE_MOD_STATUS($02FA)   // halfword
constant CI_REVISION_NUMBER($02FC)      // halfword

constant CI_USB_COMMAND_STATUS($0400)   // byte
constant CI_USB_PARAM_RESULT_0($0404)   // word
constant CI_USB_PARAM_RESULT_1($0408)   // word

constant CI_WIFI_COMMAND_STATUS($0420)  // byte
constant CI_WIFI_PARAM_RESULT_0($0424)  // word
constant CI_WIFI_PARAM_RESULT_1($0428)  // word

constant CI_EEPROM($1000)               // 2048 bytes
constant CI_WRITEBACK_LBA($1800)        // 1024 bytes (256 words)

macro CI_WAIT() {
    // requires t9 to be set to either CI_BASE or CI_BASE_EXTENDED
    PI_WAIT()
-
    lw      t0, CI_STATUS(t9)
    srl     t0, t0, 12 // first 12 bits are reserved, so ignore them
    bnez    t0,-
    nop
}

macro CI_USB_WRITE_WAIT(timeout) {
    // requires t9 to be set to either CI_BASE or CI_BASE_EXTENDED
    PI_WAIT()

    if {timeout} > 0 {
        li      v0, {timeout}
    -
        lw      t0, CI_USB_COMMAND_STATUS(t9)
        beqz    v0,+ // die
        srl     t0, t0, 4 // shift out ARM status, leaving WRITE status
        bnez    t0,-
        subiu   v0, v0, 1
        b       ++ // exit normally
        or      v0, r0, r0
    +
        li      t0, 0xF
        sw      t0, CI_USB_COMMAND_STATUS(t9) // force disarm
        lli     v0, 0xDEAD // return error code
    +

    } else {
    -
        lw      t0, CI_USB_COMMAND_STATUS(t9)
        srl     t0, t0, 4 // shift out ARM status, leaving WRITE status
        bnez    t0,-
        nop
    }
}