ld.cfg

# our cartridge is configured with 128K of RAM and 1M of ROM.
# the MMC5 mapper uses 8K banks. that gives us 16 RAM banks and 128 ROM banks.
# the MMC5 is configured to use 16K ROM windows to view 2 contiguous 8K banks at a time.
# read the MMC5 documentation for more details.
# https://www.nesdev.org/wiki/MMC5

MEMORY {
    # system RAM.
    ZEROPAGE: file = "", start = $0000,  size = $0100,  type = rw;
    STACK:    file = "", start = $0100,  size = $0100,  type = rw;
    SYS_RAM:  file = "", start = $0200,  size = $0600,  type = rw;

    # 128K of cartridge RAM dedicated to x86 processes.
    X86_RAM:  file = "", start = $0000,  size = $20000, type = rw, define = yes;

    # iNES/NES 2.0 file header.
    HEADER:   file = %O, start = $0000,  size = $0010,  type = ro, fill = yes;

    # 896K of ROM dedicated to x86 code and data.
    X86_ROM:  file = %O, start = $20000, size = $E0000, type = ro, fill = yes, define = yes;

    # unused ROM space
    UNUSED:   file = %O, start = $0000, size = $1C000, type = ro, fill = yes;

    # emulator code and data.
    EMU_ROM:  file = %O, start = $C000,  size = $4000,  type = ro, fill = yes;

    # character ROM.
    CHR_ROM:  file = %O, start = $0000,  size = $2000,  type = ro, fill = yes;
}

SEGMENTS {
    # system RAM.
    TEMP:      load = ZEROPAGE, type = zp,  define = yes;
    ZEROPAGE:  load = ZEROPAGE, type = zp,  define = yes;
    STACK:     load = STACK,    type = bss, define = yes, optional = true;
    OAM:       load = SYS_RAM,  type = bss, define = yes, optional = true;
    BSS:       load = SYS_RAM,  type = bss, define = yes;

    # cartridge RAM.
    RAM:       load = X86_RAM,  type = bss, define = yes, optional = true;

    # iNES/NES 2.0 file header.
    HEADER:    load = HEADER,   type = ro,  define = yes;

    # ELKS ROM filesystem.
    ROMFS:     load = X86_ROM,  type = ro,  define = yes, start=$80000;
    # ELKS boot code.
    BOOT:      load = X86_ROM,  type = ro,  define = yes, start=$E0000;
    # PC BIOS.
    BIOS:      load = X86_ROM,  type = ro,  define = yes, start=$F0000;

    # read-only data.
    RODATA:    load = EMU_ROM,  type = ro,  define = yes;
    # executable code.
    CODE:      load = EMU_ROM,  type = ro,  define = yes;
    # code and data that is available immediately after reset and will always remain available.
    # i.e. interrupt handlers and early initialization code.
    LOWCODE:   load = EMU_ROM,  type = ro,  define = yes, start=$F000;
    # interrupt vectors.
    VECTORS:   load = EMU_ROM,  type = ro,  define = yes, start=$FFFA;

    # character ROM.
    CHR:       load = CHR_ROM,  type = ro;
}