mirror of https://github.com/A2osX/A2osX.git
215 lines
7.8 KiB
Plaintext
215 lines
7.8 KiB
Plaintext
NEW
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AUTO 3,1
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.LIST OFF
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.OP 65C02
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.OR $2000
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.TF bin/xmastree
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*/-------------------------------------
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* # XMASTREE
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* Displays a Christmas Tree of user defined height. Ho Ho Ho.
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*
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* ## Arguments
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* **<height>**
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* Height of the tree. A positive number up to about 41 is realistic, beyond that you're on your own...
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*
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* ## Return Value
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* N/A
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*
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* ### Author
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* Original algorithm Jan 2012, Brian J. Bernstein.
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* Updated for A2osx 2021-07-02.
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*\-------------------------------------
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.INB inc/macros.i
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.INB inc/a2osx.i
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*--------------------------------------
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STAR .EQ '*'
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BLANK .EQ ' '
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MAX .EQ 30
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*--------------------------------------
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* Zero Page Segment, up to 32 bytes
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*--------------------------------------
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.DUMMY
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.OR ZPBIN
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ZS.START
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ZPPtr1 .BS 2 ; address pointer (used in arg parsing)
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ArgIndex .BS 1 ; index offset for argument parsing
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bSize .BS 2 ; arg variable - size of the tree, though we only use first byte
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ROW .BS 1 ; current row
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MARGIN .BS 1 ; number of blanks to chop from margin
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ZS.END .ED
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*--------------------------------------
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* File Header (16 Bytes)
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*--------------------------------------
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CS.START cld
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jmp (.1,x)
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.DA #$61 ; 6502,Level 1 (65c02)
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.DA #1 ; BIN Layout Version 1
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.DA #0 ; Events disabled (enable with S.PS.F.EVENT)
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.DA #0
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.DA CS.END-CS.START ; Code Size (without Constants)
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.DA DS.END-DS.START ; Data SegmentSize
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.DA #32 ; Stack Size
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.DA #ZS.END-ZS.START ; Zero Page Size
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.DA 0
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*--------------------------------------
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* Relocation Table
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*--------------------------------------
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.1 .DA CS.INIT
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.DA CS.RUN
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.DA CS.DOEVENT
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.DA CS.QUIT
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L.MSG.USAGE .DA MSG.USAGE ; msg for usage / help text
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L.MSG.NEWLINE .DA MSG.MSG.NEWLINE
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.DA 0
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*--------------------------------------
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* Called once at process creation
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* Put code for loading LIB here
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*--------------------------------------
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CS.INIT clc ; nothing to init, so just clc and return
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rts
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*--------------------------------------
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* Called until exit with CS
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* if RUN exits with CC, RUN entered again
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*--------------------------------------
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CS.RUN
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.1 inc ArgIndex ; Check next argument
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lda ArgIndex
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>SYSCALL ArgV ; check for an arg at index in A
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bcs .9 ; If doesn't exist, we're done with args
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>SYSCALL AToI
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>STYA bSize
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.2 jsr CS.RUN.Tree ; build the tree
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jmp .99
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*--- Display usage and error out ------
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.9
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>PUSHW L.MSG.USAGE ; push address for usage text
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>PUSHBI 0
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>SYSCALL PrintF ; print usage message
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lda #E.SYN ; set OS return code as Syntax Error
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sec ; indicate we don't want CS.RUN called again
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rts ; return to OS
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*--- Successful exit ------------------
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.99
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lda #0 ; set OS return code to success
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sec ; indicate we don't want CS.RUN called again
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rts ; return to OS
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*--------------------------------------
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* Called if option S.PS.F.EVENT enabled in Header
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* Timer Event : every 10th seconds
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*--------------------------------------
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CS.DOEVENT sec ; we don't use this since we don't have timer events
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rts
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*--------------------------------------
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* Called once, when RUN exited with CS
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* Put code for unloading LIB here
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*--------------------------------------
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CS.QUIT clc ; nothing to do on exit except clear carry and return
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rts
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*--------------------------------------
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CS.RUN.Tree lda bSize
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cmp #3 ; did they specify a size of 2?
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bcs CS.RUN.Start ; CC if < 3 !!! if not, go normal tree drawing
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cmp #2 ; did they specify a size of 2?
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bcc CS.RUN.Sapling ; CC if < 2 !!!
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lda #'Y'
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>SYSCALL PutChar
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jsr CS.RUN.Newline
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rts
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CS.RUN.Sapling lda #'|'
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>SYSCALL PutChar
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jsr CS.RUN.Newline
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rts
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CS.RUN.Start lda #2 ; start from row 2
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sta ROW
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lda #MAX ; calculate margin chop
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sec ; SEC before SBC !!!
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sbc bSize
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sta MARGIN
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jsr CS.RUN.Stump ; display a stump first since same as top of tree
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CS.RUN.Blanks lda #MAX ; calculate number of blanks to tab
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clc
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sbc ROW
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sbc MARGIN
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tax ; put into x register
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lda #BLANK ; load blank character
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jsr CS.RUN.Disp ; display ́x ́ blanks
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CS.RUN.Stars lda ROW ; calculate number of stars to display
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asl ; ASL not ROL !!!
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tax ; put into x register and -2
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* dex ; -1 !!! not -2
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dex
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lda #STAR ; load star character
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jsr CS.RUN.Disp ; display ́x ́ stars
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CS.RUN.Next jsr CS.RUN.Newline
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ldx ROW ; increment row
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inx
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stx ROW
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cpx bSize ; are we done?
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bne CS.RUN.Blanks
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jsr CS.RUN.Stump ; display a stump...
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rts ; ...and we ́re done
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CS.RUN.Stump lda #MAX-2 ; calculate number of blanks to place stump
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sec
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sbc MARGIN
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tax
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lda #BLANK
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jsr CS.RUN.Disp ; display ́x ́ blanks
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lda #STAR ; display star as a stump
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ldy ROW ; unless the tree is only 3 rows tall,
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cpy #3 ; then give it a much skinnier stump
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bne .2
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lda #'|' ; <-- skinny stump
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.2 >SYSCALL PutChar
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jsr CS.RUN.Newline
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rts
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CS.RUN.Disp cpx #0
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beq .9
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.1 pha
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phx
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>SYSCALL PutChar
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plx
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pla
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dex ; loop until we decrement X to 0
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bne .1
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.9 rts
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CS.RUN.Newline >PUSHW L.MSG.NEWLINE
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>PUSHBI 0
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>SYSCALL PrintF
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rts
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*--------------------------------------
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CS.END
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*--------------------------------------
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MSG.USAGE .CS "Usage : XMASTREE <size>\r\n"
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.CZ " size : height of the tree to generate\r\n"
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MSG.MSG.NEWLINE .CZ "\r\n"
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*--------------------------------------
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* Per Process DATA segment (0 filled before INIT)
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*--------------------------------------
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.DUMMY
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.OR 0
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DS.START
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DS.END .ED
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*--------------------------------------
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MAN
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SAVE usr/src/bin/xmastree.s
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ASM
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