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1 ********************************************************************
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2 * Emudsk - Virtual disk driver for CoCo emulators
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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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8 * 01 Modified to compile under OS9Source tjl 02/08/28
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9
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10 * EmuDisk floppy disk controller driver
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11 * Edition #1
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12 * 04/18/96 : Written from scratch by Alan DeKok
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13 * aland@sandelman.ocunix.on.ca
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14 *
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15 * This program is Copyright (C) 1996 by Alan DeKok,
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16 * All Rights Reserved.
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17 * License is given to individuals for personal use only.
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18 *
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19 *
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20 * Comments: Ensure that device descriptors mark it as a hard drive
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21 *
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22 *
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23 * $FF80-$FF82: logical record number
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24 LSN equ $FF80 where to put the logical sector number
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25
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26 *
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27 * $FF83: command/status register.
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28 * Output: 0=read, 1=write, 2=close.
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29 * Input: 0=no error, non-zero=error codes (see below).
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30 command equ $FF83 where to put the commands
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31
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32 *
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33 * $FF84-$FF85: 6809's 16-bit buffer address (cannot cross an 8K boundary due
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34 * to interference from the MMU emulation).
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35 buffer equ $FF84 pointer to the buffer
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36
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37 *
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38 * Returns:
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39 *
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40 * 0=successful
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41 * 2=not enabled
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42 * 4=too many MS-DOS files open,
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43 * 5=access denied (virtual HD file locked by another program
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44 * or MS-DOS read-only status)
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45 * 6/12=internal error
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46 * 254=invalid command byte
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47 * 255=power-on state or closed.
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48 *
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49 * The "close" command just flushes all the read/write buffers and
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50 * restores the metacontroller to its power-up state. The hard drive must be
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51 * enabled by the user using the MS-DOS command "ECHO >COCO3.VHD" (another
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52 * crash safeguard), so error code 2 indicates this has not been done.
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53
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54
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55 nam EmuDsk
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56 ttl os9 device driver
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57
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58 ifp1
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59 use os9defs
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60 use rbfdefs
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61 endc
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62
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63 tylg set Drivr+Objct
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64 atrv set ReEnt+rev
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65 rev set $01
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66
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67 mod eom,name,tylg,atrv,start,size
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68 fcb $ff
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69
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70 org 0
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71 u0000 rmb $FF Normal RBF device mem for 4 drives
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72 size equ .
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73
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74 fcb $FF This byte is the driver permissions
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75 name fcs /EmuDsk/
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76 fcb 1 edition #1
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77
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78
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79 * Entry: Y=Ptr to device descriptor
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80 * U=Ptr to device mem
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81 *
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82 * Default to only one drive supported, there's really no need for more.
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83 INIT lda #$FF 'Invalid' value & # of drives
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84 leax DRVBEG,u Point to start of drive tables
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85 sta ,x DD.TOT MSB to bogus value
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86 sta <V.TRAK,x Init current track # to bogus value
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87
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88 * for now, TERM routine goes here. Perhaps it should be pointing to the
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89 * park routine? ... probably not.
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90 TERM
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91 GETSTA clrb no GetStt calls - return, no error, ignore
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92 L0086 rts
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93
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94 start lbra INIT 3 bytes per entry to keep RBF happy
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95 lbra READ
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96 lbra WRITE
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97 lbra GETSTA
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98 lbra SETSTA
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99 lbra TERM
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100
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101 * Entry: B:X = LSN
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102 * Y = path dsc. ptr
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103 * U = Device mem ptr
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104 READ clra READ the sector
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105 bsr GetSect Go read the sector, exiting if there's an error
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106 tstb
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107 bne GETSTA if not sector 0, return
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108 leax ,x sets CC.Z bit
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109 bne GETSTA if not sector zero, return
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110
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111 * LSN0, standard OS-9 format
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112 * Actually, this isn't really necessary for a HD, as the information in
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113 * LSN0 never changes after it's read in once. But we'll do it anyhow
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114 ldx PD.BUF,y Get ptr to sector buffer
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115 leau DRVBEG,u point to the beginning of the drive tables
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116 ldb #DD.SIZ copy bytes over
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117 copy.0 lda ,x+ grab from LSN0
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118 sta ,u+ save into device static storage
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119 decb
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120 bne copy.0
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121 clrb
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122 rts
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123
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124 WRITE lda #$01 WRITE to emulator disk, and fall thru to GetSect
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125
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126 * Get Sector comes here with:
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127 * Entry: A = read/write command code (0/1)
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128 * B,X = LSN to read/write
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129 * Y = path dsc. ptr
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130 * U = Device static storage ptr
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131 * Exit: A = error status from command register
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132 GetSect tst <PD.DRV,y get drive number requested
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133 bne DrivErr only one drive allowed, return error
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134
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135 pshs x,b save LSN for later
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136 stb >LSN
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137 stx >LSN+1
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138
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139 ldx PD.BUF,y where the 256-byte LSN should go
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140 * Note: OS-9 allocates buffers from system memory on page boundaries, so
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141 * the low byte of X should now be $00, ensuring that the sector is not
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142 * falling over an 8K MMU block boundary.
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143
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144 stx >buffer set up the buffer address
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145 sta >command get the emulator to blast over the sector
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146 lda >command restore the error status
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147 bne FixErr if non-zero, go fix the error and exit
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148 puls b,x,pc restore LSN and exit
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149
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150 DrivErr leas 2,s kill address of calling routine (Read/Write)
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151 comb
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152 * FIND ERROR CODE TO USE
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153 * ldb #E$ find appropriate error code...
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154 ldb #E$NotRdy not ready
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155 rts
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156
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157 * Emulator error codes translated to OS-9 error codes.
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158 *
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159 * 2=not enabled
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160 * E$NotRDy - drive is not ready
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161 *
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162 * 4=too many MS-DOS files open,
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163 * E$
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164 *
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165 * 5=access denied (virtual HD file locked by another program
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166 * or MS-DOS read-only status)
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167 * E$WP - write protect
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168 *
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169 * 6/12=internal error
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170 * E$CRC - CRC error
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171 *
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172 * 254=invalid command byte
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173 * E$
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174 *
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175 * 255=power-on state or closed.
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176 * E$NotRdy - drive is not ready
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177 *
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178 FixErr leas 5,s kill B,X,PC from GetSect routine
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179 cmpa #02
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180 beq NotRdy
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181 cmpa #255
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182 beq NotRdy
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183 cmpa #5
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184 beq WP
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185 cmpa #6
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186 beq CRC
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187 cmpa #12
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188 beq CRC
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189
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190 * if it's something we don't recognize, it's a seek error
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191 comb
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192 ldb #E$Seek seek error
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193 rts
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194
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195 NotRdy comb
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196 ldb #E$NotRdy not ready
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197 rts
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198
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199 WP comb
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200 ldb #E$WP write protect
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201 rts
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202
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203 CRC comb
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204 ldb #E$CRC CRC error
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205 rts
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206
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207 L03D4 comb
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208 ldb #E$Write write error
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209 rts
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210
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211
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212 L03E0 comb
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213 ldb #E$Read Read error
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214 rts
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215
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216 SETSTA ldx PD.RGS,y Get caller's register stack ptr
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217 ldb R$B,x Get function code
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218 cmpb #SS.WTrk Write track?
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219 beq format Yes, ignore it
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220 cmpb #SS.Reset Restore head to track 0?
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221 beq format Yes, ignore it
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222 cmpb #SS.SQD sequence down the drive (i.e. park it)?
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223 beq park
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224 comb set carry for error
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225 ldb #E$UnkSvc return illegal service request error
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226 rts
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227
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228 park ldb #$02 close the drive
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229 stb >command save in command register
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230
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231 format clrb ignore physical formats. They're not
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232 rts necessary
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233
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234 emod
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235
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236 eom equ *
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