mirror of
https://github.com/dpeckett/arduino-appleii.git
synced 2025-02-27 11:28:57 +00:00
30 lines
923 B
Arduino
30 lines
923 B
Arduino
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// Hook routines for the apple II monitor program
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// Used to trick the apple code into working on this hardware
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// Ideally should patch the ROM itself, will do in future.
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void program_hooks(unsigned short addr) {
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// hook screen scroll, monitor command
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if(addr == 0xFC70) {
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screenScroll();
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PC = 0xFC95;
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}
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// hook cassette write commnand
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else if (addr == 0xFECD || addr == 0xFECF) {
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// Header length
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cassette_header((addr==0xFECD)?64:A);
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// Write Data Block
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cassette_write_block(read16(0x3C), read16(0x3E));
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// Emulate counter behaviour
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write16(0x003C, read16(0x3E));
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PC = 0xFEF5;
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}
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// hook cassette read command
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else if (addr == 0xFEFD) {
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// Read Data Block
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boolean success = cassette_read_block(read16(0x3C), read16(0x3E));
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// Emulate counter behaviour
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write16(0x003C, read16(0x3E));
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if(success) PC = 0xFF3A;
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else PC = 0xFF2D;
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}
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}
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