//*****************************************************************************
// Boot loader. Load HACK code from SPI address 0x010000 (64k) into SRAM and GO
//*****************************************************************************
//
// Put your code here:

// read data starting at address
// 0x03 0x01 0x00 0x00
    @3
    D=A
    @100
    M=D
    @1
    D=A
    @101
    M=D
    @102
    M=0
    @103
    M=0

// wake up from deep power down and wait 3us
// 0xAB
    @171
    D=A
    @SPI
    M=D
        @4
        D=A
        @COUNT
        M=D
        (DECR1)
        @COUNT
        DM=M-1
        @DECR1
        D;JGT
    @511
    D=A
    @SPI
    M=D
        @21
        D=A
        @COUNT
        M=D
        (DECR2)
        @COUNT
        DM=M-1
        @DECR2
        D;JGT

//command stack base address 
    @100
    D=A
    @READCOMMAND
    M=D
    @DIRECTION
    M=0
    @WORDCOUNT
    M=0
    @WAITREAD
    0;JEQ

(WAITREAD)
    @SPI
    D=M
    @WAITREAD
    D;JLT
    @READ
    0;JMP

(READ)
    // read
    @READCOMMAND
    A=M
    D=M
    @SPI
    M=D
    @READCOMMAND
    M=M+1
    @104
    D=A
    @READCOMMAND
    D=D-M
    @WAITREAD
    D;JGT
    @ENDREAD
    0;JMP

(ENDREAD)
    @WAITWRITE
    0;JMP

(WAITWRITE)
    @SPI
    D=M
    @WAITWRITE
    D;JLT
    @WRITE
    0;JMP

(WRITE)
    @SPI
    M=0
        @4
        D=A
        @COUNT
        M=D
        (FROMSPI)
        @COUNT
        DM=M-1
        @FROMSPI
        D;JGT
    @DIRECTION
    D=M
    @WESTWORD
    D;JEQ
    @EASTWORD
    D;JGT

(WESTWORD)
    @SPI
    D=M
    @R13
    M=D
    DM=D+M
    DM=D+M
    DM=D+M
    DM=D+M
    DM=D+M
    DM=D+M
    DM=D+M
    DM=D+M
    @DIRECTION
    M=1
    @WAITWRITE
    0;JMP

(EASTWORD)
    @WORDCOUNT
    D=M
    @SRAM_A
    M=D
    @SPI
    D=M
    @R14
    M=D
    @R13
    D=M
    @R14
    D=D+M
    @SRAM_D
    M=D
    @DIRECTION
    M=0
    @WORDCOUNT
    M=M+1
    @6
    D=A
    @WORDCOUNT
    D=D-M
    @ENDWRITE
    D;JEQ
    @WAITWRITE
    0;JMP

(ENDWRITE)
    @185
    D=A
    @SPI
    M=D
    @GO
    M=1