export interface VdpRegisterWrite {
    register: number;
    value: number;
}
export interface VramWrite {
    value: number;
}
/** Standard TMS9918 VRAM layout for Graphics II (Screen 2) */
export declare const TMS9918_LAYOUT: {
    readonly PNT: 6144;
    readonly PGT: 0;
    readonly CT: 8192;
    readonly SAT: 6912;
    readonly SPT: 14336;
};
/** SAT entry layout: Y, X, pattern, color — 4 bytes each, 32 entries */
export interface SatEntry {
    y: number;
    x: number;
    pattern: number;
    color: number;
}
/**
 * Captures writes to TMS9918 VDP ports and maintains a 16KB VRAM buffer.
 *
 * VDP register write protocol (control port):
 *   1st write: data byte (value)
 *   2nd write: register number | 0x80
 */
export declare class Tms9918 {
    private regWrites;
    private vramWrites;
    private pendingByte;
    /** 16KB VRAM buffer — populated by BIOS hooks and port writes */
    vram: Uint8Array<ArrayBuffer>;
    /** Handle a write to the VDP control port */
    writeControl(value: number): void;
    /** Handle a write to the VDP data port */
    writeData(value: number): void;
    /** Handle a read from the VDP data port */
    readData(): number;
    /** Handle a read from the VDP status port */
    readStatus(): number;
    /** Write a byte to the VRAM buffer (called by BIOS hooks) */
    writeVram(addr: number, value: number): void;
    /** Read a byte from the VRAM buffer */
    readVram(addr: number): number;
    /** Write a block of data to the VRAM buffer */
    writeVramBlock(addr: number, data: Uint8Array | number[], len: number): void;
    /** Fill a VRAM region with a byte value */
    fillVram(addr: number, value: number, len: number): void;
    /** Read a SAT entry (4 bytes: Y, X, pattern, color) */
    readSatEntry(index: number): SatEntry;
    /** Read a tile index from the Pattern Name Table */
    readPntTile(col: number, row: number): number;
    getRegisterWrites(): VdpRegisterWrite[];
    getVramWrites(): VramWrite[];
    clear(): void;
    /** Clear VRAM buffer and all recorded writes */
    clearAll(): void;
}
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