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31
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1 *******************************************
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2 * PTY
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3 * Device Driver for emulated terminal
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4 * Emulates the 6850 UART seen in usim
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5 * Protocol:
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6 * V.port is the control port.
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7 * V.port+1 is the data port. It is bidirectional.
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8 * bit 1: 1=data ready to read/0=no data
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9 * bit 2: 1=ready for output
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10 *
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11
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12 nam PTY
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13 ttl Pseudo Terminal
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14
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15 ifp1
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16 use os9defs
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17 use scfdefs
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18 endc
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19
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20 ***********************
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21 * Edition History
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22 *
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23 * # date Comments
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24 * - -------- -------------------------------
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25 * 1 16.11.01 Driver first written. SMR
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26
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27 Revision equ 1
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28
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29 org V.SCF
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30 PST equ .
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31
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32 mod PEND,PNAM,Drivr+Objct,Reent+Revision,PENT,PST
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33 fcb READ.+WRITE.
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34 PNAM fcs /PTY/
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35
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36 PENT lbra INIT
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37 lbra READ
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38 lbra WRITE
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39 lbra GETSTA
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40 lbra PUTSTA
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41 lbra TERM
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42
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43 **********************
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44 * INIT
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45 * Entry: U = Static storage
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46 * Setup the PIA
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47 *
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48 INIT clrb
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49 rts
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50
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51 **********************
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52 * READ
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53 * Entry: U = Static Storage
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54 * Y = Path Descriptor
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55 * Exit: A = Character read
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56 *
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57 * Read a byte from Port B
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58 *
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59 READ ldx V.PORT,u load port address
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60 readlp ldb ,x
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61 bitb #$01
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62 bne readbyte
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63 pshs x sleep for a bit if not
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64 ldx #1
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65 os9 f$sleep
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66 puls x
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67 bra readlp
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68 readbyte lda 1,x read byte
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69 clrb
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70 rts
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71 **********************
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72 * WRITE
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73 * Entry: U = Static storage
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74 * Y = Path Descriptor
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75 * A = Char to write
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76 *
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77 * Write a byte to Port B
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78 *
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79 WRITE ldx V.PORT,u load port address
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80 write1 ldb ,x
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81 bitb #$02
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82 bne wrt
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83 pshs x
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84 ldx #1
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85 os9 f$sleep
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86 puls x
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87 bra write1
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88 wrt sta 1,x write byte
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89 ok clrb
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90 rts
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91
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92 **********************
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93 * GETSTA
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94 * U = Static Storage
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95 * Y = Path Descriptor
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96 *
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97 GETSTA ldx PD.Rgs,y X=pointer to registers
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98 lda R$B,x A=contents of B reg.
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99 cmpa #SS.Ready check for ready code
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100 bne gsta1 if not, check next
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101 ldx V.Port,u use the PIA to determine
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102 ldb ,x if data is available
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103 bitb #$01
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104 bne ok
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105 ldb #E$NotRdy
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106 coma sets the carry flag
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107 rts
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108 gsta1 cmpa #SS.EOF check for eof code
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109 beq ok which always returns ok
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110 comb otherwise return
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111 ldb #E$UnkSVC unknown code error
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112 rts
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113
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114 **********************
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115 * PUTSTA
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116 * Always return error
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117 *
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118 PUTSTA ldx PD.Rgs,y X=register stack
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119 ldb R$B,x B=contents of reg B
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120 comb otherwise return error.
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121 ldb #E$UnkSVC
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122 rts
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123
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124 **********************
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125 * TERM
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126 * Terminate Driver
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127 *
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128 TERM clrb
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129 rts
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130
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131 emod
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132 PEND equ *
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133
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