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1 ********************************************************************
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2 * oscode - OS-9 Level One V2 bootstrap code
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3 *
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4 * $Id$
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5 *
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6 * Ed. Comments Who YY/MM/DD
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7 * ------------------------------------------------------------------
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201
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8 * From Tandy OS-9 Level One VR 02.00.00
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9
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6
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10 ifp1
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11 use defsfile
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6
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12 endc
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13
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14 * Initial code executed upon booting up to OS-9
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15 org $2600
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16
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17 Start fcc /OS/
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18 bra L2620
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19
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20 fdb $1204
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21 BootMsg fcc /OSy/
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22 fcb $60
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23 fcc /BOOT/
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24
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25 L2620 clr PIA.U4+3
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26 sta $FFDF turn off ROM
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27 * locate Boot Text Screen at $8000
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28 ldb #$06
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29 ldx #$FFC6
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30 L262B sta ,x++
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31 decb
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32 bne L262B
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33 sta 1,x
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34
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35 * clear screen at $8000
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36 ldx #$8000
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37 ldy #$0200
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38 lda #$60
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39 L263B sta ,x+
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40 leay -1,y
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41 bne L263B
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42
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43 * Copy "OS9 BOOT" to screen area
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44 ldx #$810C
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45 leay <BootMsg,pcr
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46 ldb #$08
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47 L2649 lda ,y+
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48 sta ,x+
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49 decb
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50 bne L2649
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51
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52 ldd #$1212
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53 cmpd <$0078
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54 beq L266E
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55 leau >Start,pcr
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56 ldx #$0F80
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57 ldy #$EF00
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58 L2663 lda ,u+
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59 sta ,y+
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60 leax -1,x
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61 bne L2663
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62 jmp >$EF5C
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63 L266E leax <eoc,pcr
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64 ldd $09,x
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65 jmp d,x
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66
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67 eoc equ *
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68 end
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69
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