| Chase H.Q. | Routines |
| Prev: E810 | Up: Map | Next: E9B4 |
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Used by the routine at entrypt_48k.
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| stop_the_tape_48k | E8FE | CALL setup_interrupts | Call setup_interrupts | |
| E901 | CALL reset_music | Call reset_music | ||
| E904 | EI | Enable interrupts | ||
| E905 | HALT | Wait for next interrupt | ||
| E906 | CALL clear_screen | Call clear_screen | ||
| E909 | LD HL,$E9B4 | -> "STOP THE TAPE" + "PRESS ANY KEY" message set | ||
| E90C | CALL menu_draw_strings | Call menu_draw_strings | ||
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Wait for a key down.
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| stt_wait_for_keypress_loop | E90F | CALL play_music_48k | Call play_music_48k during the loop | |
| E912 | XOR A | Was any key pressed? | ||
| E913 | IN A,($FE) | |||
| E915 | CPL | |||
| E916 | AND $1F | |||
| E918 | JR Z,stt_wait_for_keypress_loop | Loop if not | ||
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Wait for key up.
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| stt_debounce_loop | E91A | CALL play_music_48k | Call play_music_48k during the loop | |
| E91D | XOR A | Was any key pressed? | ||
| E91E | IN A,($FE) | |||
| E920 | CPL | |||
| E921 | AND $1F | |||
| E923 | JR NZ,stt_debounce_loop | Loop if it was | ||
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Draw the input selection menu.
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| stt_clear_screen | E925 | CALL clear_screen | Call clear_screen | |
| E928 | LD HL,$E9E1 | Point HL at input menu messages (NUL terminated) | ||
| E92B | CALL menu_draw_strings | Call menu_draw_strings | ||
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Wait for a choice.
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| stt_keyscan_choice | E92E | CALL play_music_48k | Call play_music_48k during the loop | |
| E931 | LD A,$F7 | Keyscan for 1, 2, 3, 4, 5 | ||
| E933 | IN A,($FE) | |||
| E935 | CPL | |||
| E936 | AND $1F | |||
| E938 | JR Z,stt_keyscan_choice | Loop while no selection | ||
| E93A | RRA | 1. SINCLAIR JOYSTICK selected | ||
| E93B | JR C,stt_sinclair_joystick | |||
| E93D | RRA | 2. CURSOR JOYSTICK selected | ||
| E93E | JR C,stt_cursor_joystick | |||
| E940 | RRA | 3. KEMPSTON JOYSTICK selected | ||
| E941 | JR C,stt_kempston_joystick | |||
| E943 | RRA | 4. KEYBOARD selected | ||
| E944 | JR C,stt_keyboard | |||
| E946 | CALL redefine_keys_48k | 5. DEFINE KEYS selected | ||
| E949 | JR stt_clear_screen | Loop | ||
| stt_sinclair_joystick | E94B | LD HL,$EE26 | Point at Sinclair joystick keydefs | |
| E94E | JR stt_copy_keydefs | Jump to copy keydefs | ||
| stt_cursor_joystick | E950 | LD HL,$EE2B | Point at cursor joystick keydefs | |
| stt_copy_keydefs | E953 | LD DE,$EE38 | Copy the five keydefs at HL to $EE38 | |
| E956 | LD BC,$0005 | |||
| E959 | LDIR | |||
| stt_keyboard | E95B | XOR A | Clear Kempston joystick flag | |
| stt_do_define | E95C | LD HL,$EE3D | Point at final three bytes of temp_keydefs | |
| E95F | LD DE,$A0CC | Assign Kempston joystick flag | ||
| E962 | LD (DE),A | |||
| E963 | INC DE | Populate Quit/Pause/Turbo keys at $A0CD+ | ||
| E964 | LD BC,$0003 | |||
| E967 | LDIR | |||
| E969 | LD HL,$EE38 | Populate Gear/Accelerate/Brake/Left/Right keys at $A0D2+ | ||
| E96C | LD C,$05 | |||
| E96E | LDIR | |||
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Warn the player that they can't return to this screen.
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| E970 | CALL clear_screen | Call clear_screen | ||
| E973 | LD HL,$EB78 | Address of "control options cannot be remodified" text (NUL terminated) | ||
| E976 | CALL menu_draw_strings | Call menu_draw_strings | ||
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Wait for key up.
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| stt_debounce_loop2 | E979 | CALL play_music_48k | Call play_music_48k | |
| E97C | XOR A | Was a key pressed? | ||
| E97D | IN A,($FE) | |||
| E97F | CPL | |||
| E980 | AND $1F | |||
| E982 | JR NZ,stt_debounce_loop2 | Loop if it was | ||
| stt_confirm | E984 | CALL play_music_48k | Call play_music_48k | |
| E987 | LD A,$DF | Was Y pressed? | ||
| E989 | IN A,($FE) | |||
| E98B | CPL | |||
| E98C | AND $10 | |||
| E98E | JR NZ,stt_done | Jump to done if so | ||
| E990 | LD A,$7F | Was N pressed? | ||
| E992 | IN A,($FE) | |||
| E994 | CPL | |||
| E995 | AND $08 | |||
| E997 | JR NZ,stt_clear_screen | Start over if so | ||
| E999 | JR stt_confirm | Loop | ||
| stt_done | E99B | DI | Disable interrupts | |
| E99C | JP clear_screen | Jump to clear_screen | ||
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Check for a stable reading from the Kempston joystick port before allowing the user to proceed.
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| stt_kempston_joystick | E99F | LD B,$0A | 10 iterations | |
| E9A1 | IN A,($1F) | Read the joystick port into C | ||
| E9A3 | LD C,A | |||
| stt_kempston_loop | E9A4 | IN A,($1F) | Read the same port again | |
| E9A6 | CP C | If it doesn't match then jump back to menu | ||
| E9A7 | JR NZ,stt_keyscan_choice | |||
| E9A9 | PUSH BC | Call play_music_48k | ||
| E9AA | CALL play_music_48k | |||
| E9AD | POP BC | |||
| E9AE | DJNZ stt_kempston_loop | Loop while B > 0 | ||
| E9B0 | LD A,$01 | Set Kempston joystick flag | ||
| E9B2 | JR stt_do_define | Jump to do define | ||
| Prev: E810 | Up: Map | Next: E9B4 |