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88 lines
1.9 KiB
Markdown
88 lines
1.9 KiB
Markdown
[< back to index](../index.md)
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# NES/Famicom-oriented modules
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## nes_hardware
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The `nes_hardware` module is imported automatically on NES targets.
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TODO
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## nes_mmc4
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The `nes_mmc4` module is imported automatically on the NES MMC4 target.
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and contains routines related to MMC4 bankswitching.
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#### `void set_prg_bank(byte a)`
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Changes the $8000-$BFFF PRG bank.
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#### `void set_chr_bank0(byte a)`
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Changes the CHR bank 0 ($0000-$0fff in the PPU memory space).
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The high nibble (0 or 1) selects between `chrrom0` and `chrrom1` segments.
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The low nibble L (0-$F) selects a 4K-aligned address in the segment ($L000).
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#### `void set_chr_bank1(byte a)`
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Changes the CHR bank 1 ($1000-$1fff in the PPU memory space).
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The high nibble (0 or 1) selects between `chrrom0` and `chrrom1` segments.
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The low nibble L (0-$F) selects a 4K-aligned address in the segment ($L000).
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#### `void set_vertical_mirroring()`
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Switches nametable mirroring to vertical.
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#### `void set_horizontal_mirroring()`
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Switches nametable mirroring to horizontal.
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## nes_joy
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Provides an interface for reading joypads that is compatible with the `joy` module.
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#### `alias input_a = input_btn`
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1 if A button pressed, 0 id not pressed.
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#### `byte input_b`
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1 if B button pressed, 0 id not pressed.
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#### `byte input_select`
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1 if Select button pressed, 0 id not pressed.
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#### `byte input_start`
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1 if Start button pressed, 0 id not pressed.
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#### `void read_joy1()`
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Reads the joypad from the port 1.
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#### `void read_joy2()`
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Reads the joypad from the port 2.
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#### `void read_also_joy1()`
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Reads the joypad from the port 1 and adds its readouts to the current readouts.
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#### `void read_also_joy2()`
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Reads the joypad from the port 2 and adds its readouts to the current readouts.
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#### `void nes_reset_joy()`
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Resets the state variables.
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Unlike `reset_joy`, this resets all the NES button states.
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## nes_joy1_default
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Defines the joystick in port 1 as the default joystick.
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#### `alias read_joy = read_joy1`
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