2019-07-15 14:21:50 +02:00
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[< back to index](../doc_index.md)
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2018-07-12 18:30:35 +02:00
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2019-06-26 15:51:09 +02:00
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## keyboard
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The `keyboard` module provides support for reading keypresses from the keyboard.
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Not supported on all targets.
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#### `byte readkey()`
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Waits for and reads a single keypress.
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The returning values may vary between platforms:
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* letters may be uppercase or lowercase
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* modifier keys may be applied or ignored
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Available for:
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Commodore 64 (requires KERNAL),
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Commodore 16 or Plus/4 (requires KERNAL),
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Commodore 128 (requires KERNAL),
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VIC 20 (requires KERNAL),
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Atari,
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Amstrad CPC,
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ZX Spectrum,
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NEC PC-88.
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#### `const byte KEY_ENTER`
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Key code for the Enter/Return key. Usually 13, but not always.
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2018-12-19 19:01:53 +01:00
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## err
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2018-07-12 18:30:35 +02:00
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2018-12-19 19:01:53 +01:00
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#### `enum error_number`
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Standard error codes. All codes other than `err_ok` suggest that the last operation failed.
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#### `error_number errno`
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The result of the last operation.
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2018-12-30 18:59:32 +01:00
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## random
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A simple and reasonably fast random number generator. Not suitable for cryptographic or simulation uses.
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#### `word rand_seed`
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Random number generator state.
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#### `byte rand()`
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Get a random byte (0–255) and update the state of the generator.
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#### `void init_rand_seed()`
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Initializes the random number generator state.
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This may take a long time, even several frames, depending on the target.
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Current implementation:
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* On C64, spends two frames reading noise data from the SID chip.
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* On Z80, reads the refresh register.
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* On all other targets, sets the seed to 1.
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