337 lines
8.9 KiB
Plaintext
337 lines
8.9 KiB
Plaintext
;-------------------------------------------------------------------------
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; This is an serial interface version of the well known Woz monitor.
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; Much of the original code has been preserved with slight additions
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; regarding the IO of the serial interface.
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;-------------------------------------------------------------------------
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#define serial_ready BASE + $000 + OFFSET
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#define serial_read BASE + $080 + OFFSET
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#define serial_write BASE + $081 + OFFSET
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;-------------------------------------------------------------------------
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; Memory declaration
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;-------------------------------------------------------------------------
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; Last "opened" location Low
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#define XAML $24
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; Last "opened" location High
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#define XAMH $25
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; Store address Low
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#define STL $26
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; Store address High
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#define STH $27
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; Hex value parsing Low
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#define L $28
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; Hex value parsing High
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#define H $29
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; Used to see if hex value is given
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#define YSAV $2A
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; $00=XAM, $7F=STOR, $AE=BLOCK XAM
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#define MODE $2B
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; current serial mode
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#define SERIAL_MODE $2C
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#define SERIAL_MODE_WRITE $01
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#define SERIAL_MODE_READ $FF
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; Input buffer
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#define IN $0200
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;-------------------------------------------------------------------------
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; Constants
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;-------------------------------------------------------------------------
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; Backspace key, arrow left key
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#define BS $08
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; Carriage Return
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#define CR $0D
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; Dot character
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#define DOT "."
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; Colon character
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#define COLON ":"
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; ESC key
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#define ESC $1B
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; Prompt character
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#define PROMPT "\"
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#define SPACE $20
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;-------------------------------------------------------------------------
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; Let's get started
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;-------------------------------------------------------------------------
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* = BASE + $600 + OFFSET
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.dsb (*-end_of_counter_remote), 0
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* = BASE + $600 + OFFSET
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reset
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jsr reset_serial
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jsr prep_serial_write;Enable serial write mode
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cld ;Clear decimal arithmetic mode
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cli ;Enable interrupts
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ldy #$7F
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; Program falls through to the getline routine to save some program bytes
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; Please note that Y holds $7F, which will cause an automatic Escape
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;-------------------------------------------------------------------------
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; The getline process
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;-------------------------------------------------------------------------
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notcr
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cmp #BS ;Backspace key?
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beq backspace ;Yes
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cmp #ESC ;ESC?
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beq escape ;Yes
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iny ;Advance text index
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bpl nextchar ;Auto ESC if line longer than 127
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escape
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lda #PROMPT ;Print prompt character
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jsr serial_echo ;Output it.
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getline
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lda #CR ;Send CR
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jsr serial_echo
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ldy #0+1 ;Start a new input line
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backspace
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dey ;Backup text index
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bmi getline ;Oops, line's empty, reinitialize
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nextchar
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jsr prep_serial_read;Prepare for read
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lda serial_ready ;Character received?
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beq nextchar ;Loop if not
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lda serial_read ;Read character
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sta IN,Y ;Add to text buffer
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jsr prep_serial_write;Prepare for write
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cmp #BS ;Do not print control characters
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beq afterecho
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cmp #ESC
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beq afterecho
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jsr serial_echo ;Display character
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afterecho
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cmp #CR
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bne notcr ;It's not CR!
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; Line received, now let's parse it
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ldy #$FF ;Reset text index (orig -1)
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lda #0 ;Default mode is XAM
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tax ;X=0
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setstor
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asl ;Leaves $7B if setting STOR mode
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setmode
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sta MODE ;Set mode flags
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blskip
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iny ;Advance text index
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nextitem
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lda IN,Y ;Get character
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cmp #CR
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beq getline ;We're done if it's CR!
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cmp #DOT
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bcc blskip ;Ignore everything below "."!
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beq setxam ;Set BLOCK XAM mode
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cmp #COLON
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beq setstormode ;Set STOR mode! $BA will become $7B
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cmp #"R"
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beq run ;Run the program! Forget the rest
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cmp #"r"
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beq run ;Run the program on lowercase r
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stx L ;Clear input value (X=0)
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stx H
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sty YSAV ;Save Y for comparison
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; Here we're trying to parse a new hex value
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nexthex
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lda IN,Y ;Get character for hex test
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eor #$30 ;Map digits to 0-9
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cmp #9+1 ;Is it a decimal digit?
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bcc dig ;Yes!
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adc #$A8 ;Map letter "a"-"f" to $FA-FF
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cmp #$FA ;Hex letter?
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bcs dig ;Yes!
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adc #$E0 ;Map letter "A"-"F" to $FA-FF
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cmp #$FA ;Hex letter?
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bcc nothex ;No! Character not hex
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dig
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asl
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asl ;Hex digit to MSD of A
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asl
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asl
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ldx #4 ;Shift count
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hexshft
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asl ;Hex digit left, MSB to carry
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rol L ;Rotate into LSD
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rol H ;Rotate into MSD's
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dex ;Done 4 shifts?
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bne hexshft ;No, loop
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iny ;Advance text index
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bne nexthex ;Always taken
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nothex
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cpy YSAV ;Was at least 1 hex digit given?
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beq toescape ;No! Ignore all, start from scratch
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bit MODE ;Test MODE byte
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bvc notstor ;B6=0 is STOR, 1 is XAM or BLOCK XAM
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; STOR mode, save LSD of new hex byte
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lda L ;LSD's of hex data
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sta (STL,X) ;Store current 'store index'(X=0)
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inc STL ;Increment store index.
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bne nextitem ;No carry!
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inc STH ;Add carry to 'store index' high
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tonextitem
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jmp nextitem ;Get next command item.
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toescape
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jmp escape
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setxam
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ora #$80
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jmp setmode
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setstormode
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ora #$80
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jmp setstor
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;-------------------------------------------------------------------------
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; run user's program from last opened location
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;-------------------------------------------------------------------------
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run
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jmp (XAML) ;Run user's program
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;-------------------------------------------------------------------------
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; We're not in Store mode
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;-------------------------------------------------------------------------
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notstor
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bmi xamnext ;B7 = 0 for XAM, 1 for BLOCK XAM
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; We're in XAM mode now
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ldx #2 ;Copy 2 bytes
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setadr
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lda L-1,X ;Copy hex data to
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sta STL-1,X ; 'store index'
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sta XAML-1,X ; and to 'XAM index'
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dex ;Next of 2 bytes
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bne setadr ;Loop unless X = 0
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; Print address and data from this address, fall through next bne.
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nxtprnt
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bne pr_data ;NE means no address to print
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lda #CR ;Print CR first
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jsr serial_echo
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lda XAMH ;Output high-order byte of address
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jsr pr_byte
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lda XAML ;Output low-order byte of address
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jsr pr_byte
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lda #COLON ;Print colon
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jsr serial_echo
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pr_data
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lda #SPACE ;Print space
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jsr serial_echo
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lda (XAML,X) ;Get data from address (X=0)
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jsr pr_byte ;Output it in hex format
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xamnext
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stx MODE ;0 -> MODE (XAM mode).
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lda XAML ;See if there's more to print
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cmp L
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lda XAMH
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sbc H
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bcs tonextitem ;Not less! No more data to output
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inc XAML ;Increment 'examine index'
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bne mod8chk ;No carry!
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inc XAMH
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mod8chk
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lda XAML ;If address MOD 8 = 0 start new line
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and #%00000111
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bpl nxtprnt ;Always taken.
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;-------------------------------------------------------------------------
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; Subroutine to print a byte in A in hex form (destructive)
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;-------------------------------------------------------------------------
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pr_byte
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pha ;Save A for LSD
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lsr
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lsr
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lsr ;MSD to LSD position
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lsr
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jsr pr_hex ;Output hex digit
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pla ;Restore A
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; Fall through to print hex routine
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;-------------------------------------------------------------------------
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; Subroutine to print a hexadecimal digit
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;-------------------------------------------------------------------------
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pr_hex
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and #%00001111 ;Mask LSD for hex print
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ora #"0" ;Add "0"
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cmp #"9"+1 ;Is it a decimal digit?
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bcc serial_echo ;Yes! output it
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adc #6 ;Add offset for letter A-F; skip ASCII signs
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; Fall through to print routine
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;-------------------------------------------------------------------------
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; Subroutine to print a character to the terminal
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;-------------------------------------------------------------------------
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serial_echo
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pha
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serial_echo_wait
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lda serial_ready
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beq serial_echo_wait ;Not yet ready to write data
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pla
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sta serial_write ;Write byte
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rts
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prep_serial_write
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pha
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lda #SERIAL_MODE_WRITE
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sta SERIAL_MODE
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sta serial_write
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pla
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rts
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prep_serial_read
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pha
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lda SERIAL_MODE
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cmp #SERIAL_MODE_WRITE
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bne prep_serial_read_end
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lda #SERIAL_MODE_READ
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sta SERIAL_MODE
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lda serial_read
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prep_serial_read_end
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pla
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rts
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