mirror of
https://github.com/EranMorkon/AMTS.git
synced 2023-12-28 16:48:38 +00:00
203 lines
13 KiB
Plaintext
203 lines
13 KiB
Plaintext
1 ;******************************************************************************
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2 ;* Z80 Assembler program *
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3 ;* Josef Reisinger *
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4 ;* josef.reisinger@htl-hl.ac.at *
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5 ;* 10/07/2017 *
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6 ;******************************************************************************
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7
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8
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9 ; ---------------------------- PIO 82C55 I/O ---------------------------------
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10 0080 PIO_A: EQU $80 ; (INPUT)
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11 0081 PIO_B: EQU $81 ; (OUTPUT) OUT TO LEDS
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12 0082 PIO_C: EQU $82 ; (INPUT) IN from DIP SWITCHES
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13 0083 PIO_CON: EQU $83 ; CONTROL BYTE PIO 82C55
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14
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15
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16 ; --------------------------- CTC Z80 Timer Counter --------------------------
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17 0000 CTC0 EQU $00 ; Channel 0
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18 0001 CTC1 EQU $01 ; Channel 1
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19 0002 CTC2 EQU $02 ; Channel 2
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20 0003 CTC3 EQU $03 ; Channel 3
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21
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22 ; -------------------------- SIO (USART) ----------------------------------------
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23 0040 SIO_A_D: EQU $40 ; Channel A Data Register
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24 0041 SIO_B_D: EQU $41 ; Channel B Data Register
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25 0042 SIO_A_C: EQU $42 ; Channel A Control Register
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26 0043 SIO_B_C: EQU $43 ; Channel B Control Register
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27
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28
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29 ;-------------------------- CONSTANTS ----------------------------------------
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30 FFFF RAMTOP: EQU $FFFF ; 32Kb RAM 8000H-FFFFH
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31 000D CR: EQU $0D
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32 000A LF: EQU $0A
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33 0020 SPACE: EQU $20
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34
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35 ;******************************************************************************
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36 ;* RESET HANDLER *
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37 ;* Function: Start Main Program *
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38 ;******************************************************************************
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39 0000 ORG $0000
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40 0000 C3 00 01 JP MAIN ; jump to Main program
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41
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42
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43 ;******************************************************************************
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44 ;* NMI HANDLER *
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45 ;* Handles NMI Interrupt Request *
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46 ;******************************************************************************
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47 0066 ORG $0066
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48 0066 21 A1 01 LD HL,NMI_TEXT ; Send NMI to V24
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49 0069 CD 80 01 CALL SIO_PUT_STRING
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50 006C ED 45 RETN
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51
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52 ;******************************************************************************
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53 ;* MAIN PROGRAM *
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54 ;******************************************************************************
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55 0100 ORG $100
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56 0100 F3 MAIN: DI ; Disable interrupt
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57 0101 31 FF FF LD SP,RAMTOP ; Set stack pointer
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58 0104 CD 1F 01 CALL PIO_INIT ; Init PIO (8255)
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59 0107 CD 24 01 CALL CTC_INIT ; Initialize CTC Channl1 for 9600 Baud (SIO Channel A)
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60 010A CD 2D 01 CALL SIO_INIT ; Animalize SIO for character based transfer (9600,n,8,1)
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61 010D 21 91 01 LD HL,START_TEXT ; Send Welcome Text to V24
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62 0110 CD 80 01 CALL SIO_PUT_STRING
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63 0113 CD 63 01 _AGAIN: CALL SIO_GET_CHAR ; Wait for Character on V24
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64 0116 7B LD A,E ; Output Error to LED's
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65 0117 D3 81 OUT (PIO_B),A
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66 0119 CD 56 01 CALL SIO_PUT_CHAR ; Echo Character to V24
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67 011C C3 13 01 JP _AGAIN
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68 011F ;
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69
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70 ;******************************************************************************
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71 ;* Initialize PIO (8255) *
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72 ;******************************************************************************
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73 011F 3E 99 PIO_INIT: LD A,$99 ; Init PIO 8255 Control Word:
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74 0121 ; PA0-PA7=IN (DIP SWITCHES)
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75 0121 ; PB0-PB7=OUT (LEDS),
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76 0121 D3 83 OUT (PIO_CON),A ; PC0-PC7=IN, Mode 0 Selection
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77 0123 C9 RET
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78
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79 ;******************************************************************************
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80 ;* Initialize CTC Channel 1 (SIO Channel A Clock) *
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81 ;******************************************************************************
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82 0124 3E 05 CTC_INIT: LD A,$05 ; Init Timer Counter - Channel 1
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83 0126 D3 01 OUT (CTC1),A ; for Baudrate 9600 (No Interrupt, Timer Mode, PSC=16,
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84 0128 ; trigger on positive edge
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85 0128 3E 0C LD A,$0C ; Write Time constant 12*16*552ns= 105,98s
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86 012A D3 01 OUT (CTC1),A
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87 012C C9 RET
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88
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89
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90 ;******************************************************************************
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91 ;* Initialize SIO Channel A for character based transfer *
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92 ;******************************************************************************
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93 012D 3E 30 SIO_INIT: LD A,$30 ; Write to WR0 Register --> Error Reset
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94 012F D3 42 OUT (SIO_A_C),A
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95 0131 3E 18 LD A,$18 ; Write to WR0 Register --> Channel Reset
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96 0133 D3 42 OUT (SIO_A_C),A
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97 0135 3E 04 LD A,$04 ; Select WR4 Register
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98 0137 D3 42 OUT (SIO_A_C),A
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99 0139 3E 04 LD A,$04 ; CLK*1, 1STOP Bit, No Parity
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100 013B D3 42 OUT (SIO_A_C),A
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101 013D 3E 03 LD A,$03 ; Select WR3 Register
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102 013F D3 42 OUT (SIO_A_C),A
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103 0141 3E C1 LD A,$C1 ; RX enable,8 Data Bits
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104 0143 D3 42 OUT (SIO_A_C),A
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105 0145 3E 05 LD A,$05 ; Select WR5 Register
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106 0147 D3 42 OUT (SIO_A_C),A
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107 0149 3E 68 LD A,$68 ; TX enable,8 Data Bits, DTR inactive, RTS inactive,Break off
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108 014B D3 42 OUT (SIO_A_C),A
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109 014D 3E 01 LD A,$1 ; Select WR1 Register
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110 014F D3 42 OUT (SIO_A_C),A
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111 0151 3E 00 LD A,$0 ; No Interrupts for Rx and Tx Characters
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112 0153 D3 42 OUT (SIO_A_C),A
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113 0155 C9 RET
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114
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115
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116
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117 ;******************************************************************************
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118 ;* Send one Character Via SIO Channel A(Polling Mode) *
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119 ;* D- Register: Character to send (ASCII Code) *
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120 ;******************************************************************************
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121 0156 F5 SIO_PUT_CHAR: PUSH AF
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122 0157 DB 42 _TX_READY: IN A,(SIO_A_C) ; Read RRO Register
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123 0159 CB 57 BIT 2,A ; TX Buffer empty ?
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124 015B CA 57 01 JP Z,_TX_READY ; No --> Wait
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125 015E 7A LD A,D ; load character in A
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126 015F D3 40 OUT (SIO_A_D),A ; Send character (Transfer Buffer)
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127 0161 F1 POP AF
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128 0162 C9 RET
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129
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130
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131 ;******************************************************************************
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132 ;* Receive one Character Via SIO Channel A(Polling Mode) *
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133 ;* D- Register: Character received (ASCII Code) *
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134 ;* E-Register: Error Code *
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135 ;******************************************************************************
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136 0163 F5 SIO_GET_CHAR: PUSH AF
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137 0164 DB 42 _RX_READY: IN A,(SIO_A_C) ; Read RRO Register
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138 0166 CB 47 BIT 0,A ; RX Character Available ?
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139 0168 CA 64 01 JP Z,_RX_READY ; No --> Wait
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140 016B DB 40 IN A,(SIO_A_D) ; Store character
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141 016D 57 LD D,A
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142 016E 3E 01 LD A,$01 ; Select WR1 Register
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143 0170 D3 42 OUT (SIO_A_C),A
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144 0172 DB 42 IN A,(SIO_A_C) ; Read Error Register
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145 0174 5F LD E,A ; store Error Status
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146 0175 E6 70 AND $70 ; only D6(CRC Framing Error),D5(Rx Overrun Error) und D4 (Parity Error)
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147 0177 CA 7E 01 JP Z,_RX_EXIT ; return if no error
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148 017A 3E 30 LD A,$30 ; reset Error
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149 017C D3 42 OUT (SIO_A_C),A
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150 017E F1 _RX_EXIT: POP AF
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151 017F C9 RET
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152
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153
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154 ;******************************************************************************
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155 ;* SEND STRING to V24 via SIO *
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156 ;* HL: contains start address of string *
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157 ;******************************************************************************
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158 0180 F5 SIO_PUT_STRING: PUSH AF
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159 0181 7E _NEXT_CHAR: LD A,(HL) ; get character
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160 0182 FE 00 CP $00 ; END of String ?
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161 0184 CA 8F 01 JP Z,_TEXT_END
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162 0187 57 LD D,A
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163 0188 CD 56 01 CALL SIO_PUT_CHAR ; send character
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164 018B 23 INC HL ; next character
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165 018C C3 81 01 JP _NEXT_CHAR
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166 018F F1 _TEXT_END: POP AF
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167 0190 C9 RET
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168
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169
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170 ;******************************************************************************
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171 ;* TEXT DEFINITIONS *
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172 ;******************************************************************************
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173 0191 0D 0A 5A 38 START_TEXT: DEFB CR,LF,'Z','8','0',SPACE,'D','E','M','O',SPACE,'V','1','.','0',$00
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0195 30 20 44 45
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0199 4D 4F 20 56
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019D 31 2E 30 00
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174 01A1 0D 0A 4E 4D NMI_TEXT: DEFB CR,LF,'N','M','I',$00
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01A5 49 00
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175
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176
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177
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178
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179
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180
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181
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182
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183
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Symbol table:
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CR 000D CTC0 0000 CTC1 0001
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CTC2 0002 CTC3 0003 CTC_INIT 0124
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LF 000A MAIN 0100 NMI_TEXT 01A1
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PIO_A 0080 PIO_B 0081 PIO_C 0082
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PIO_CON 0083 PIO_INIT 011F RAMTOP FFFF
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SIO_A_C 0042 SIO_A_D 0040 SIO_B_C 0043
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SIO_B_D 0041 SIO_GET_CHAR 0163 SIO_INIT 012D
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SIO_PUT_CHAR 0156 SIO_PUT_STRING 0180 SPACE 0020
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START_TEXT 0191 _AGAIN 0113 _NEXT_CHAR 0181
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_RX_EXIT 017E _RX_READY 0164 _TEXT_END 018F
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_TX_READY 0157
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31 symbols.
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