.export _SD_command

.importzp sp

.autoimport on

; void SD_command(uint8_t cmd, uint32_t arg, uint8_t crc)

; The plan: push crc to stack, load arg into tmp1 through 4

.proc   _SD_command:    near

        pha                     ; Push CRC to cpu stack
        ldy     #$04
        lda     (sp),y          ; Load CMD
        ora     #$40            ; start bit
        jsr     _spi_exchange

        dey
arg_loop:                       ; send ARG
        lda     (sp),y
        jsr     _spi_exchange      
        dey
        bpl     arg_loop

        pla                     ; Pull CRC from stack
        ora     #$01            ; stop bit
        jsr     _spi_exchange
        jsr     incsp5          ; pop all off stack
        rts

.endproc