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1345
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1 **************************************************
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2 * System Call: F$FreeHB
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3 *
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4 * Function: Get free high block
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5 *
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6 * Called from F$MapBlk and from SS.MpGPB)
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7 *
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8 * Input: B = Block count
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9 * Y = DAT image pointer
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10 *
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11 * Output: A = High block number
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12 *
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13 * Error: CC = C bit set; B = error code
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14 *
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1145
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15 FFreeHB ldb R$B,u Get # blocks requested
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16 ldy R$Y,u Get DAT Img ptr
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17 bsr L0A31 Go find free blocks in high part of DAT
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18 L0A2C bcs L0A30 Couldn't find any, exit with error
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19 sta R$A,u Save starting block #
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20 L0A30 rts Return
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21
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22 L0A31 tfr b,a Copy # blocks requested to A
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23 * This gets called directly from within F$Link
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24 L0A33 suba #$09 Invert within 8
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25 nega
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26 pshs x,d Save X, block # & block count
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27 ldd #$FFFF -1'
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28 L0A56 pshs d
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29
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1258
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30 * Move to next block - SHOULD OPTIMIZE WITH W
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1145
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31 L0A58 clra # free blocks found so far=0
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32 ldb 2,s Get block #
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33 addb ,s Add block increment (point to next block)
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34 stb 2,s Save new block # to check
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35 cmpb 1,s Same as block count?
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36 bne L0A75 No, skip ahead
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37 ldb #E$MemFul Preset error for 207 (Process mem full)
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38 cmpy <D.SysDAT Is it the system process?
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39 bne L0A6C No, exit with error 207
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1387
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40 ldb #E$NoRAM System Mem full (237)
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1145
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41 L0A6C stb 3,s Save error code
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42 comb set carry
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43 bra L0A82 Exit with error
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44
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45 L0A71 tfr a,b Copy # blocks to B
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46 addb 2,s Add to current start block #
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47 L0A75 lslb Multiply block # by 2
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48 ldx b,y Get DAT marker for that block
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49 cmpx #DAT.Free Empty block?
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50 bne L0A58 No, move to next block
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51 inca Bump up # blocks free counter
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52 cmpa 3,s Have we got enough?
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53 bne L0A71 No, keep looking
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54 L0A82 leas 2,s Eat temporary stack
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55 puls d,x,pc Restore reg, error code & return
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56
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1345
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57
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58 * WHERE DOES THIS EVER GET CALLED FROM???
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59 * Rodney says: "It's called via os9p1 syscall vector in line 393"
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1145
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60 FSFreeLB ldb R$B,u Get block count
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61 ldy R$Y,u Get ptr to DAT Image
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62 bsr L0A4B Go find block #'s
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63 bra L0A2C Do error checking & exit (since never called,
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64 * not worried about speed)
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65
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66 L0A4B lda #$FF Value to start loop at block 0
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67 pshs x,d Preserve X,flag & block count
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68 * lda #$01 # to add to go to next block (positive here)
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69 nega -(-1)=+1
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70 subb #9 Drop block count to -8 to -1 (invert within 8)
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71 negb Negate so it is a positive # again
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72 bra L0A56 Go into main find loop
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73
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1345
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74
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75 **************************************************
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76 * System Call: F$FreeLB
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77 *
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78 * Function: Get free low block
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79 *
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80 * Input: B = Block count
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81 * Y = DAT image pointer
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82 *
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83 * Output: A = Low block number
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84 *
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85 * Error: CC = C bit set; B = error code
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86 *
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1145
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87 FFreeLB ldd R$D,u
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88 ldx R$X,u
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89 ldu R$U,u
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90 L0A8C pshs d,x,y,u
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91 leay <P$DATImg,x
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92 lsla
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93 leay a,y
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94 IFNE H6309
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95 clra
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96 lslb
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97 tfr d,w
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98 tfm u+,y+
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99 oim #ImgChg,P$State,x
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100 ELSE
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1250
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101 lslb
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102 L0ALoop lda ,u+
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103 sta ,y+
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1145
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104 decb
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105 bne L0ALoop
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106 lda P$State,x
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107 ora #ImgChg
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108 sta P$State,x
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109 ENDC
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110 clrb
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111 puls d,x,y,u,pc
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