1 | | ------------------------------------------------------------------------------
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2 | | viint.s -- VSDD Vertical Interval interrupt handler for the Buchla 700
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3 | | Version 17 -- 1989-12-19 -- D.N. Lynx Crowe
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4 |
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5 | | VIint
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6 |
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7 | | VSDD Vertical Interval interrupt handler. Enables display of
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8 | | any object whose bit is set in vi_ctl. Bit 0 = object 0, etc.
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9 |
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10 | | SetPri() uses BIOS(B_SETV, 25, VIint) to set the interrupt
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11 | | vector and lets VIint() enable the object. If vi_dis
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12 | | is set, SetPri() won't enable the interrupt or set the vector
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13 | | so that several objects can be started up at once.
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14 |
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15 | | This routine also sets the base address and scroll offset
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16 | | for the score display object if vi_sadr is non-zero,
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17 | | after a delay for VSDD FRAMESTOP synchronization.
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18 | | ------------------------------------------------------------------------------
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19 | .text
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20 |
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21 | .xdef _VIint | Vertical Interval int. handler
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22 |
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23 | .xdef _vi_sadr | score object base address
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24 | .xdef _vi_scrl | score object scroll offset
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25 | .xdef lclsadr | local scroll address
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26 | .xdef lclscrl | local scroll offset
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27 | .xdef vdelay | VSDD scroll delay
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28 |
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29 | .xdef VIct1 | VSDD interrupt R11
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30 | .xdef VIct2 | VSDD interrupt R11
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31 | .xdef VIct3 | VSDD interrupt R11
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32 | .xdef VIct4 | VSDD interrupt R11
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33 |
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34 | .xref _v_regs | VSDD registers
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35 | .xref _v_odtab | VSDD object descriptor table
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36 |
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37 | .xref _vi_clk | scroll delay timer
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38 | .xref _vi_ctl | unblank control word
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39 | .xref _vi_tag | VSDD 'needs service' tag
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40 |
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41 | .page
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42 |
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43 | | Miscellaneous equates:
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44 | | ----------------------
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45 |
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46 | DELAY = 17 | FRAMESTOP sync delay in Ms
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47 | STACKSR = 32 | offset to sr on stack
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48 | V_BLA = 4 | V_BLA (blank) bit number
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49 | VSDD_R5 = 10 | VSDD R5 byte offset in _v_regs
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50 | VSDD_R11 = 22 | VSDD R11 byte offset in _v_regs
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51 |
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52 | VT_BASE = 128 | word offset of VSDD Access Table
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53 |
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54 | VT_1 = VT_BASE+300 | high time
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55 | VT_2 = VT_BASE+2 | low time
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56 | | ------------------------------------------------------------------------------
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57 |
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58 | | Stack picture after movem.l at entry:
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59 | | -------------------------------------
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60 |
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61 | | LONG PC +34
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62 | | WORD SR +32 STACKSR
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63 | | LONG A6 +28
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64 | | LONG A2 +24
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65 | | LONG A1 +20
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66 | | LONG A0 +16
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67 | | LONG D3 +12
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68 | | LONG D2 +8
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69 | | LONG D1 +4
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70 | | LONG D0 +0
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71 |
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72 | | ------------------------------------------------------------------------------
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73 |
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74 | .page
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75 |
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76 | | _VIint -- Vertical interval interrupt handler
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77 | | ------ -----------------------------------
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78 | _VIint: movem.l d0-d3/a0-a2/a6,-(a7) | save registers
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79 | addi.w #0x0100,STACKSR(a7) | raise IPL in sr on the stack
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80 |
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81 | move.w _v_regs+VSDD_R11,VIct1 | save the VSDD R11 value
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82 |
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83 | tst.w _vi_sadr | see if we should scroll
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84 | beq viunbl | jump if not
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85 |
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86 | | ------------------------------------------------------------------------------
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87 | | setup delayed scroll parameters
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88 | | ------------------------------------------------------------------------------
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89 | move.w _v_regs+VSDD_R5,d0 | get VSDD R5
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90 | move.w d0,d1 | save it for later
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91 | andi.w #0x0180,d0 | see if we're already in bank 0
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92 | beq dlyscrl | jump if so
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93 |
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94 | clr.w _v_regs+VSDD_R5 | set bank 0
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95 |
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96 | move.w _v_regs+VSDD_R11,VIct2 | save the VSDD R11 value
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97 |
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98 | vw1a: cmp.w #VT_1,_v_regs+VSDD_R11 | wait for FRAMESTOP
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99 | bcc vw1a | ...
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100 |
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101 | vw2a: cmp.w #VT_1,_v_regs+VSDD_R11 | ...
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102 | bcs vw2a | ...
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103 |
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104 | vw3a: cmp.w #VT_1,_v_regs+VSDD_R11 | ...
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105 | bcc vw3a | ...
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106 |
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107 | vw4a: cmp.w #VT_2,_v_regs+VSDD_R11 | ...
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108 | bcs vw4a | ...
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109 |
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110 | dlyscrl: tst.w _vi_tag | wait for previous scroll
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111 | bne dlyscrl | ...
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112 |
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113 | move.w _vi_sadr,lclsadr | save address for timeint
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114 | move.w _vi_scrl,lclscrl | save offset for timeint
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115 | clr.w _vi_sadr | reset for next time
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116 | clr.w _vi_scrl | ...
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117 | move.w vdelay,_vi_clk | set the scroll delay timer
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118 | st _vi_tag | set the 'need service' tag
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119 | | ------------------------------------------------------------------------------
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120 | | check for unblank requests
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121 | | ------------------------------------------------------------------------------
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122 | move.w _vi_ctl,d2 | get the unblank control word
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123 | beq viexit | exit if nothing to unblank
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124 |
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125 | bra unblnk | go unblank some objects
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126 |
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127 | viunbl: move.w _vi_ctl,d2 | get the unblank control word
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128 | beq vidone | exit if nothing to unblank
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129 |
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130 | move.w _v_regs+VSDD_R5,d0 | get VSDD R5
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131 | move.w d0,d1 | save it for later
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132 | andi.w #0x0180,d0 | see if we're already in bank 0
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133 | beq unblnk | jump if so
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134 |
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135 | clr.w _v_regs+VSDD_R5 | set bank 0
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136 |
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137 | move.w _v_regs+VSDD_R11,VIct3 | save the VSDD R11 value
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138 |
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139 | vw1b: cmp.w #VT_1,_v_regs+VSDD_R11 | wait for FRAMESTOP
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140 | bcc vw1b | ...
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141 |
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142 | vw2b: cmp.w #VT_1,_v_regs+VSDD_R11 | ...
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143 | bcs vw2b | ...
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144 |
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145 | vw3b: cmp.w #VT_1,_v_regs+VSDD_R11 | ...
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146 | bcc vw3b | ...
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147 |
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148 | vw4b: cmp.w #VT_2,_v_regs+VSDD_R11 | ...
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149 | bcs vw4b | ...
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150 |
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151 | .page
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152 |
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153 | | ------------------------------------------------------------------------------
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154 | | unblank objects indicated by contents of d2 (loaded earlier from _vi_ctl)
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155 | | ------------------------------------------------------------------------------
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156 |
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157 | unblnk: clr.w d3 | clear the counter
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158 | clr.w _vi_ctl | clear the unblank control word
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159 | lea _v_odtab,a1 | point at first object
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160 |
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161 | vicheck: btst d3,d2 | check the object bit
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162 | beq vinext | go check next one if not set
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163 |
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164 | move.w (a1),d0 | get v_odtab[obj][0]
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165 | bclr #V_BLA,d0 | clear the blanking bit
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166 | move.w d0,(a1) | set v_odtab[obj][0]
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167 |
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168 | vinext: cmpi.w #15,d3 | see if we're done
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169 | beq viexit | jump if so
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170 |
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171 | addq.l #8,a1 | point at next object
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172 | addq.w #1,d3 | increment object counter
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173 | bra vicheck | go check next object
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174 |
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175 | | ------------------------------------------------------------------------------
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176 | | switch back to the bank the interrupted code was using if we changed it
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177 | | ------------------------------------------------------------------------------
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178 |
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179 | viexit: move.w d1,d0 | see if we were in bank 0
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180 | andi.w #0x0180,d0 | ...
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181 | beq vidone | jump if so
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182 |
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183 | viwait: tst.w _vi_tag | wait for timer to run out
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184 | bne viwait | ... so timeint sees bank 0
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185 |
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186 | move.w d1,_v_regs+VSDD_R5 | restore v_regs[5] to old bank
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187 |
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188 | move.w _v_regs+VSDD_R11,VIct4 | save the VSDD R11 value
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189 |
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190 | vw1c: cmp.w #VT_1,_v_regs+VSDD_R11 | wait for FRAMESTOP
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191 | bcc vw1c | ...
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192 |
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193 | vw2c: cmp.w #VT_1,_v_regs+VSDD_R11 | ...
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194 | bcs vw2c | ...
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195 |
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196 | vw3c: cmp.w #VT_1,_v_regs+VSDD_R11 | ...
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197 | bcc vw3c | ...
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198 |
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199 | vw4c: cmp.w #VT_2,_v_regs+VSDD_R11 | ...
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200 | bcs vw4c | ...
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201 |
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202 | | ------------------------------------------------------------------------------
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203 | | restore registers and return to interrupted code
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204 | | ------------------------------------------------------------------------------
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205 |
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206 | vidone: movem.l (a7)+,d0-d3/a0-a2/a6 | restore registers
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207 | rte | return from interrupt
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208 |
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209 | .page
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210 |
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211 | | ------------------------------------------------------------------------------
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212 | .data
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213 | | ------------------------------------------------------------------------------
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214 |
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215 | vdelay: .dc.w DELAY | VSDD scroll delay
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216 |
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217 | | ------------------------------------------------------------------------------
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218 | .bss
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219 | | ------------------------------------------------------------------------------
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220 |
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221 | _vi_sadr: .ds.w 1 | score object base address
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222 | _vi_scrl: .ds.w 1 | score object scroll offset
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223 |
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224 | lclsadr: .ds.w 1 | local copy of vi_sadr
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225 | lclscrl: .ds.w 1 | local copy of vi_scrl
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226 |
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227 | VIct1: .ds.w 1 | VSDD R11 value at interrupt
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228 | VIct2: .ds.w 1 | VSDD R11 value at interrupt
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229 | VIct3: .ds.w 1 | VSDD R11 value at interrupt
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230 | VIct4: .ds.w 1 | VSDD R11 value at interrupt
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231 |
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232 | .end
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