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1 ********************************************************************
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2 * Boot - Disto RAMPak Boot Module
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3 *
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4 * $Id$
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5 *
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6 * Edt/Rev YYYY/MM/DD Modified by
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7 * Comment
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8 * ------------------------------------------------------------------
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9 * 5 ????/??/?? Alan DeKok
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10 * Created.
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11 *
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12 * 6 1998/10/20 Boisy G. Pitre
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13 * Fixed small bugs, improved speed.
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14
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15 nam Boot
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16 ttl Disto RAMPak Boot Module
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17
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18 * Disassembled 94/06/25 11:37:47 by Alan DeKok
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19
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20 IFP1
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21 use defsfile
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22 ENDC
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23
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24 tylg set Systm+Objct
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25 atrv set ReEnt+rev
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26 rev set $00
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27 edition set 6
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28
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29 mod eom,name,tylg,atrv,start,size
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30
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31 * on-stack buffer to use
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32 org 0
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33 size equ .
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34
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35 name equ *
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36 fcs /Boot/
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37 fcb edition
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38
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39 start orcc #IntMasks ensure IRQ's are off.
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40
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41 pshs x,d save 4 bytes of junk
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42 R.D equ 1
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43 R.X equ 3
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44
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45 lda >MPI.Slct get current slot
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46 pshs a save off
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47 lda >PakSlot,pcr get multipak slot number
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48 bmi cont if >127, invalid slot number
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49 anda #$03 force it to be legal
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50 ldb #$11
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51 mul put it into both nibbles
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52 stb >MPI.Slct go to the desired slot
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53
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54 cont ldd #$0001 request one byte (will round up to 1 page)
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55 os9 F$SRqMem request the memory
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56 bcs L00AE exit on error
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57 * U is implicitely the buffer address to use
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58
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59 ldx #$0000 X=0: got to sector #$0000
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60 bsr GetSect load in LSN0, and point Y to the buffer
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61 bcs L00AE
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62
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63 ldd <DD.BSZ,u size of the bootstrap file
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64 std R.D,s save it on the stack (0,s is junk)
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65 ldx <DD.BT+1,u get starting sector of the bootstrap file
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66
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67 pshs x save the starting sector number
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68 ldd #$0100 one page of memory
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69 os9 F$SRtMem return the copy of LSN0 to free memory
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70
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71 ldd R.X,s get size of boot memory to request
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72 IFGT Level-1
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73 os9 F$BtMem ask for the boot memory
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74 ELSE
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75 os9 F$SRqMem ask for the boot memory
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76 ENDC
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77 puls x restore the starting sector number
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78 bcs L00AE no memory: exit with error
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79
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80 stu R.X,s save start address of memory allocated
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81 std R.D,s and the size of the boot memory
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82 beq L00A7 if no memory allocated, exit
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83
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84 SectLp pshs x,d save sector #, size of boot
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85 bsr GetSect read one sector
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86 bcs L00AC if there's an error, exit
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87 puls x,d restor sector, size of boot
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88
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89 leau $0100,u go up one page in memory
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90 leax $01,x go to the next sector
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91 subd #$0100 take out one sector, need value in B, too.
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92 bhi SectLp loop until all sectors are read
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93
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94 L00A7 puls a
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95 sta >MPI.Slct
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96 clrb clear carry
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97 puls d return size of boot memory to user
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98 bra L00B0 and go exit
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99
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100 L00AC leas $04,s remove X,D off of stack
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101 L00AE puls a
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102 sta >MPI.Slct
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103 leas $02,s kill D off of the stack
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104
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105 L00B0 puls x restore start address of memory allocated
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106 * leas size,s remove the on-stack buffer
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107 clr >DPort stop the disk
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108 L00BA rts
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109
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110 * GetSect: read a sector off of the disk
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111 * Entry: X = sector number to read
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112 GetSect pshs d,x,y
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113 ldy >Address,pcr grab the device address
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114 tfr x,d move 16 bit LSN into 2 8-bit registers
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115 sta 2,y save HB LSN
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116 stb 1,y save LB LSN
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117 leax ,u get buffer address to write into
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118 clrb and start out at byte zero
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119
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120 ReadLp stb ,y save byte number
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121 lda 3,y grab the byte
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122 sta ,x+ save in the buffer
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123 incb go to the enxt byte
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124 bne ReadLp
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125 clrb no errors
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126 puls d,x,y,pc restore registers and return
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127
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128 IFGT Level-1
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129 Pad fill $39,$1D0-6-*
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130 ENDC
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131
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132 Address fdb $FF40 address of the device to boot from
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133 PakSlot fcb $01 multipak slot number
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134
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135 emod
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136 eom equ *
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137 end
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