Trait ZxMemory 

pub trait ZxMemory {
    const ROM_SIZE: usize;
    const RAMTOP: u16;
    const PAGES_MAX: u8;
    const SCR_BANKS_MAX: usize;
    const ROM_BANKS_MAX: usize;
    const RAM_BANKS_MAX: usize;
    const PAGE_SIZE: usize = 16_384usize;

    // Required methods
    fn reset(&mut self);
    fn read(&self, addr: u16) -> u8;
    fn read16(&self, addr: u16) -> u16;
    fn read_screen(&self, screen_bank: usize, addr: u16) -> u8;
    fn write(&mut self, addr: u16, val: u8);
    fn write16(&mut self, addr: u16, val: u16);
    fn mem_ref(&self) -> &[u8] ;
    fn mem_mut(&mut self) -> &mut [u8] ;
    fn screen_ref(&self, screen_bank: usize) -> Result<&ScreenArray>;
    fn screen_mut(&mut self, screen_bank: usize) -> Result<&mut ScreenArray>;
    fn page_kind(&self, page: u8) -> Result<MemoryKind>;
    fn page_bank(&self, page: u8) -> Result<(MemoryKind, usize)>;
    fn page_ref(&self, page: u8) -> Result<&[u8]>;
    fn page_mut(&mut self, page: u8) -> Result<&mut [u8]>;
    fn rom_bank_ref(&self, rom_bank: usize) -> Result<&[u8]>;
    fn rom_bank_mut(&mut self, rom_bank: usize) -> Result<&mut [u8]>;
    fn ram_bank_ref(&self, ram_bank: usize) -> Result<&[u8]>;
    fn ram_bank_mut(&mut self, ram_bank: usize) -> Result<&mut [u8]>;
    fn map_rom_bank(&mut self, rom_bank: usize, page: u8) -> Result<()>;
    fn map_ram_bank(&mut self, ram_bank: usize, page: u8) -> Result<()>;

    // Provided methods
    fn map_exrom(&mut self, _exrom_bank: ExRom, _page: u8) -> Result<()> { ... }
    fn unmap_exrom(&mut self, _exrom_bank: &ExRom) { ... }
    fn is_exrom_at(&self, _page: u8) -> bool { ... }
    fn has_mapped_exrom(&self, _exrom_bank: &ExRom) -> bool { ... }
    fn page_index_at(&self, address: u16) -> Result<MemPageOffset> { ... }
    fn rom_ref(&self) -> &[u8]  { ... }
    fn rom_mut(&mut self) -> &mut [u8]  { ... }
    fn ram_ref(&self) -> &[u8]  { ... }
    fn ram_mut(&mut self) -> &mut [u8]  { ... }
    fn load_into_rom<R: Read>(&mut self, rd: R) -> Result<()> { ... }
    fn load_into_rom_bank<R: Read>(
        &mut self,
        rom_bank: usize,
        rd: R,
    ) -> Result<()> { ... }
    fn iter_pages<A: RangeBounds<u16>>(
        &self,
        address_range: A,
    ) -> Result<MemPageRefIter<'_, Self>> { ... }
    fn for_each_page_mut<A: RangeBounds<u16>, F>(
        &mut self,
        address_range: A,
        f: F,
    ) -> Result<()>
       where for<'a> F: FnMut(PageMutSlice<'a>) -> Result<()> { ... }
    fn load_into_mem<A: RangeBounds<u16>, R: Read>(
        &mut self,
        address_range: A,
        rd: R,
    ) -> Result<()> { ... }
    fn fill_mem<R, F>(&mut self, address_range: R, f: F) -> Result<()>
       where R: RangeBounds<u16>,
             F: FnMut() -> u8 { ... }
}

A trait for interfacing ZX Spectrum’s various memory types.

Required Associated Constants

const ROM_SIZE: usize

The size of the whole ROM, not just one bank.

const RAMTOP: u16

The last available memory address.

const PAGES_MAX: u8

A maximum value allowed for a page argument.

const SCR_BANKS_MAX: usize

A maximum value allowed for a screen_bank argument

const ROM_BANKS_MAX: usize

A maximum value allowed for a rom_bank argument

const RAM_BANKS_MAX: usize

A maximum value allowed for a ram_bank argument

Provided Associated Constants

const PAGE_SIZE: usize = 16_384usize

This is just a hint. Actual page sizes may vary.

Required Methods

fn reset(&mut self)

Resets memory banks.

fn read(&self, addr: u16) -> u8

If addr is above RAMTOP the function should return std::u8::MAX.

fn read16(&self, addr: u16) -> u16

If addr is above RAMTOP the function should return std::u16::MAX.

fn read_screen(&self, screen_bank: usize, addr: u16) -> u8

Reads a byte from screen memory at the given addr.

The screen banks are different from memory banks. E.g. for Spectrum 128k then screen bank 0 resides in a memory bank 5 and screen bank 1 resides in a memory bank 7. For 16k/48k Spectrum, there is only one screen bank: 0.

addr is in screen address space (0 addresses the first byte of screen memory).

Panics

If addr is above the upper limit of screen memory address space the function should panic. If screen_bank doesn’t exist the function should also panic.

fn write(&mut self, addr: u16, val: u8)

If addr is above RAMTOP the function should do nothing.

fn write16(&mut self, addr: u16, val: u16)

If addr is above RAMTOP the function should do nothing.

fn mem_ref(&self) -> &[u8]

Provides a continuous view into the whole memory (all banks: ROM + RAM).

fn mem_mut(&mut self) -> &mut [u8]

Provides a continuous view into the whole memory (all banks: ROM + RAM).

fn screen_ref(&self, screen_bank: usize) -> Result<&ScreenArray>

Returns a reference to the screen memory.

See ZxMemory::read_screen for an explanation of screen_bank argument.

fn screen_mut(&mut self, screen_bank: usize) -> Result<&mut ScreenArray>

Returns a mutable reference to the screen memory.

See ZxMemory::read_screen for an explanation of screen_bank argument.

fn page_kind(&self, page: u8) -> Result<MemoryKind>

Returns an enum describing what kind of memory is currently paged at the specified page.

If an EX-ROM bank is currently mapped at the specified page a MemoryKind::Rom will be returned in this instance.

page should be less or equal to PAGES_MAX.

fn page_bank(&self, page: u8) -> Result<(MemoryKind, usize)>

Returns a tuple of an enum describing what kind of memory and which bank of that memory is currently paged at the specified page.

Note

Unlike ZxMemory::page_kind this method ignores if an EX-ROM bank is currently mapped at the specified page. In this instance, the returned value corresponds to a memory bank that would be mapped at the page if the EX-ROM bank wasn’t mapped.

page should be less or equal to PAGES_MAX.

fn page_ref(&self, page: u8) -> Result<&[u8]>

page should be less or equal to PAGES_MAX.

fn page_mut(&mut self, page: u8) -> Result<&mut [u8]>

page should be less or equal to PAGES_MAX.

fn rom_bank_ref(&self, rom_bank: usize) -> Result<&[u8]>

rom_bank should be less or equal to ROM_BANKS_MAX.

fn rom_bank_mut(&mut self, rom_bank: usize) -> Result<&mut [u8]>

rom_bank should be less or equal to ROM_BANKS_MAX.

fn ram_bank_ref(&self, ram_bank: usize) -> Result<&[u8]>

ram_bank should be less or equal to RAM_BANKS_MAX.

fn ram_bank_mut(&mut self, ram_bank: usize) -> Result<&mut [u8]>

ram_bank should be less or equal to RAM_BANKS_MAX.

fn map_rom_bank(&mut self, rom_bank: usize, page: u8) -> Result<()>

rom_bank should be less or equal to ROM_BANKS_MAX and page should be less or equal to PAGES_MAX.

fn map_ram_bank(&mut self, ram_bank: usize, page: u8) -> Result<()>

ram_bank should be less or equal to RAM_BANKS_MAX and page should be less or equal to PAGES_MAX.

Provided Methods

fn map_exrom(&mut self, _exrom_bank: ExRom, _page: u8) -> Result<()>

Maps EX-ROM bank at the specified page.

exrom_bank should be one of the attachable EX-ROMS and page should be less or equal to PAGES_MAX.

Only one EX-ROM can be mapped at the same time. If an EX-ROM bank is already mapped when calling this function it will be unmapped first, regardless of the page, the previous EX-ROM bank has been mapped at.

Not all types of memory support attaching external ROMs.

fn unmap_exrom(&mut self, _exrom_bank: &ExRom)

Unmaps an external ROM if the currently mapped EX-ROM bank is the same as in the argument. Otherwise does nothing.

fn is_exrom_at(&self, _page: u8) -> bool

Returns true if an EX-ROM bank is currently being mapped at the specified memory page.

fn has_mapped_exrom(&self, _exrom_bank: &ExRom) -> bool

Returns true if a specified EX-ROM bank is currently being mapped.

fn page_index_at(&self, address: u16) -> Result<MemPageOffset>

Returns Ok(MemPageOffset) if address is equal to or less than ZxMemory::RAMTOP.

fn rom_ref(&self) -> &[u8]

Provides a continuous view into the ROM memory (all banks).

fn rom_mut(&mut self) -> &mut [u8]

Provides a continuous mutable view into the ROM memory (all banks).

fn ram_ref(&self) -> &[u8]

Provides a continuous view into RAM (all banks).

fn ram_mut(&mut self) -> &mut [u8]

Provides a continuous mutable view into RAM (all banks).

fn load_into_rom<R: Read>(&mut self, rd: R) -> Result<()>

The data read depends on how big ROM is ZxMemory::ROM_SIZE. Results in an error when the ROM data size is less than the ROM_SIZE.

fn load_into_rom_bank<R: Read>(&mut self, rom_bank: usize, rd: R) -> Result<()>

Results in an error when the ROM data size is less than the ROM bank’s size.

fn iter_pages<A: RangeBounds<u16>>( &self, address_range: A, ) -> Result<MemPageRefIter<'_, Self>>

Returns an iterator of memory page slice references intersecting with a given address range.

Errors

May return an ZxMemoryError::UnsupportedAddressRange error.

fn for_each_page_mut<A: RangeBounds<u16>, F>( &mut self, address_range: A, f: F, ) -> Result<()>

where for<'a> F: FnMut(PageMutSlice<'a>) -> Result<()>,

Iterates over mutable memory page slices PageMutSlice intersecting with a given address range passing the slices to the closure f.

Errors

May return an ZxMemoryError::UnsupportedAddressRange error or an error returned by the provided closure.

fn load_into_mem<A: RangeBounds<u16>, R: Read>( &mut self, address_range: A, rd: R, ) -> Result<()>

Reads data into a paged-in memory area at the given address range.

fn fill_mem<R, F>(&mut self, address_range: R, f: F) -> Result<()>

where R: RangeBounds<u16>, F: FnMut() -> u8,

Fills currently paged-in pages with the data produced by the closure F.

Useful to fill RAM with random bytes.

Provide the address range.

NOTE: this will overwrite both ROM and RAM locations.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors