BIOS RAM locations
(by Bruce Tomlin, modified by Christopher Salomon)
$C800: Vec_Snd_Shadow Shadow of sound chip registers (15 bytes) $C80F: Vec_Btn_State Current state of all joystick buttons $C810: Vec_Prev_Btns Previous state of all joystick buttons $C811: Vec_Buttons Current toggle state of all buttons $C812: Vec_Button_1_1 Current toggle state of stick 1 button 1 $C813: Vec_Button_1_2 Current toggle state of stick 1 button 2 $C814: Vec_Button_1_3 Current toggle state of stick 1 button 3 $C815: Vec_Button_1_4 Current toggle state of stick 1 button 4 $C816: Vec_Button_2_1 Current toggle state of stick 2 button 1 $C817: Vec_Button_2_2 Current toggle state of stick 2 button 2 $C818: Vec_Button_2_3 Current toggle state of stick 2 button 3 $C819: Vec_Button_2_4 Current toggle state of stick 2 button 4 $C81A: Vec_Joy_Resltn Joystick A/D resolution ($80=min $00=max) $C81B: Vec_Joy_1_X Joystick 1 left/right $C81C: Vec_Joy_1_Y Joystick 1 up/down $C81D: Vec_Joy_2_X Joystick 2 left/right $C81E: Vec_Joy_2_Y Joystick 2 up/down $C81F: Vec_Joy_Mux Joystick enable/mux flags (4 bytes) $C81F: Vec_Joy_Mux_1_X Joystick 1 X enable/mux flag (=1) $C820: Vec_Joy_Mux_1_Y Joystick 1 Y enable/mux flag (=3) $C821: Vec_Joy_Mux_2_X Joystick 2 X enable/mux flag (=5) $C822: Vec_Joy_Mux_2_Y Joystick 2 Y enable/mux flag (=7) $C823: Vec_Misc_Count Misc counter/flag byte, zero when not in use $C824: Vec_0Ref_Enable Check0Ref enable flag $C825: Vec_Loop_Count Loop counter word (incremented in Wait_Recal) $C827: Vec_Brightness Default brightness $C828: Vec_Dot_Dwell Dot dwell time? $C829: Vec_Pattern Dot pattern (bits) $C82A: Vec_Text_HW Default text height and width $C82A: Vec_Text_Height Default text height $C82B: Vec_Text_Width Default text width $C82C: Vec_Str_Ptr Temporary string pointer for Print_Str $C82E: Vec_Counters Six bytes of counters $C82E: Vec_Counter_1 First counter byte $C82F: Vec_Counter_2 Second counter byte $C830: Vec_Counter_3 Third counter byte $C831: Vec_Counter_4 Fourth counter byte $C832: Vec_Counter_5 Fifth counter byte $C833: Vec_Counter_6 Sixth counter byte $C834: Vec_RiseRun_Tmp Temp storage word for rise/run $C836: Vec_Angle Angle for rise/run and rotation calculations $C837: Vec_Run_Index Index pair for run $C839: * Pointer to copyright string during startup $C839: Vec_Rise_Index Index pair for rise $C83B: * High score cold-start flag (=0 if valid) $C83B: Vec_RiseRun_Len length for rise/run $C83C: * temp byte $C83D: Vec_Rfrsh Refresh time (divided by 1.5MHz) $C83D: Vec_Rfrsh_lo Refresh time low byte $C83E: Vec_Rfrsh_hi Refresh time high byte $C83F: Vec_Music_Work Music work buffer (14 bytes, backwards?) $C842: Vec_Music_Wk_A register 10 $C843: * register 9 $C844: * register 8 $C845: Vec_Music_Wk_7 register 7 $C846: Vec_Music_Wk_6 register 6 $C847: Vec_Music_Wk_5 register 5 $C848: * register 4 $C849: * register 3 $C84A: * register 2 $C84B: Vec_Music_Wk_1 register 1 $C84C: * register 0 $C84D: Vec_Freq_Table Pointer to note-to-frequency table (normally $FC8D) $C84F: Vec_Max_Players Maximum number of players for Select_Game $C850: Vec_Max_Games Maximum number of games for Select_Game $C84F: Vec_ADSR_Table Storage for first music header word (ADSR table) $C851: Vec_Twang_Table Storage for second music header word ('twang' table) $C853: Vec_Music_Ptr Music data pointer $C853: Vec_Expl_ChanA Used by Explosion_Snd - bit for first channel used? $C854: Vec_Expl_Chans Used by Explosion_Snd - bits for all channels used? $C855: Vec_Music_Chan Current sound channel number for Init_Music $C856: Vec_Music_Flag Music active flag ($00=off $01=start $80=on) $C857: Vec_Duration Duration counter for Init_Music $C858: Vec_Music_Twang 3 word 'twang' table used by Init_Music $C858: Vec_Expl_1 4 bytes copied from Explosion_Snd's U-reg parameters $C859: Vec_Expl_2 $C85A: Vec_Expl_3 $C85B: Vec_Expl_4 $C85C: Vec_Expl_Chan Used by Explosion_Snd - channel number in use? $C85D: Vec_Expl_ChanB Used by Explosion_Snd - bit for second channel used? $C85E: Vec_ADSR_Timers ADSR timers for each sound channel (3 bytes) $C861: Vec_Music_Freq Storage for base frequency of each channel (3 words) $C85E: * Scratch 'score' storage for Display_Option (7 bytes) $C867: Vec_Expl_Flag Explosion_Snd initialization flag? $C868: Unused? $C869: Unused? $C86a: Unused? $C86b: Unused? $C86c: Unused? $C86d: Unused? $C86e: Unused? $C86f: Unused? $C870: Unused? $C871: Unused? $C872: Unused? $C873: Unused? $C874: Unused? $C875: Unused? $C876: Unused? $C877: Vec_Expl_Timer Used by Explosion_Snd $C878: Unused? $C879: Vec_Num_Players Number of players selected in Select_Game $C87A: Vec_Num_Game Game number selected in Select_Game $C87B: Vec_Seed_Ptr Pointer to 3-byte random number seed (=$C87D) $C87D: Vec_Random_Seed Default 3-byte random number seed : * $C880 - $CBEA is user RAM : : $CBEA: Vec_Default_Stk Default top-of-stack $CBEB: Vec_High_Score High score storage (7 bytes) $CBF2: Vec_SWI3_Vector SWI2/SWI3 interrupt vector (3 bytes) $CBF2: Vec_SWI2_Vector SWI2/SWI3 interrupt vector (3 bytes) $CBF5: Vec_FIRQ_Vector FIRQ interrupt vector (3 bytes) $CBF8: Vec_IRQ_Vector IRQ interrupt vector (3 bytes) $CBFB: Vec_SWI_Vector SWI/NMI interrupt vector (3 bytes) $CBFB: Vec_NMI_Vector SWI/NMI interrupt vector (3 bytes) $CBFE: Vec_Cold_Flag Cold start flag (warm start if = $7321)