# Othello (U)

## Status

**Pass 3 complete; promoted.** `prg.s` is a traced disassembly with all
address-derived labels replaced, all `jsr`/`jmp` operands symbolic, hardware
registers named via `symbols.inc`, and `apply_symbols.py` reporting 0 residue.
Code coverage: 14,220 / 32,768 bytes (43.4%).
`make` assembles and verifies byte-identical to `rom.nes`.

## ROM

| Property | Value |
|----------|-------|
| Format | iNES |
| Mapper | 0 (NROM) |
| PRG | 32 KB |
| CHR | 8 KB |
| Mirroring | Horizontal |
| NMI vector | $D6B4 |
| RESET vector | $8000 |
| IRQ vector | $804E |

## Power-on flow

RESET enters at `$8000`:

    sei                            ; CPU:$8000 PRG:0000  78
    lda #$00                       ; CPU:$8001 PRG:0001  A9 00
    sta PPUCTRL                    ; CPU:$8003 PRG:0003  8D 00 20
    sta PPUMASK                    ; CPU:$8006 PRG:0006  8D 01 20
    lda PPUSTATUS                  ; CPU:$8009 PRG:0009  AD 02 20
    bpl Reset_OnNonnegative        ; CPU:$800C PRG:000C  10 FB
    lda PPUSTATUS                  ; CPU:$800E PRG:000E  AD 02 20
    bmi Reset_OnNegative           ; CPU:$8011 PRG:0011  30 FB
    lda PPUSTATUS                  ; CPU:$8013 PRG:0013  AD 02 20
    bpl Reset_OnNonnegative2       ; CPU:$8016 PRG:0016  10 FB
    lda PPUSTATUS                  ; CPU:$8018 PRG:0018  AD 02 20
    bmi Reset_OnNegative2          ; CPU:$801B PRG:001B  30 FB

NMI handler at `$D6B4`:

    pha                            ; CPU:$D6B4 PRG:56B4  48
    txa                            ; CPU:$D6B5 PRG:56B5  8A
    pha                            ; CPU:$D6B6 PRG:56B6  48
    tya                            ; CPU:$D6B7 PRG:56B7  98
    pha                            ; CPU:$D6B8 PRG:56B8  48
    lda #$00                       ; CPU:$D6B9 PRG:56B9  A9 00
    sta OAMADDR                    ; CPU:$D6BB PRG:56BB  8D 03 20
    lda #$02                       ; CPU:$D6BE PRG:56BE  A9 02

## Data-table inventory (Pass 3)

- `$8350-$8367` (24 bytes) - `BoardCellParameterTable`
- `$851E-$854D` (48 bytes) - `PlayerColorNameTable`
- `$8661-$8699` (57 bytes) - `GameModeNameTable`
- `$884A-$888A` (65 bytes) - `BoardCellNameTable`
- `$8B57-$8B66` (16 bytes) - `SlotGameText`
- `$8C80-$8C8B` (12 bytes) - `PushBButtonText`
- `$9003-$9012` (16 bytes) - `BoardMoveOffsetTable`
- `$92BF-$9336` (120 bytes) - `BoardCellCharsetTable`
- `$9555-$9561` (13 bytes) - `VsScreenLayoutTable`
- `$95AD-$95D6` (42 bytes) - `VsScreenLayoutTable2`
- `$9784-$97C3` (64 bytes) - `VsScreenLayoutTable3`
- `$98E0-$98F0` (17 bytes) - `PushAButtonText`
- `$9967-$997D` (23 bytes) - `CannotCancelText`
- `$999B-$99AB` (17 bytes) - `AgainstLevelText`
- `$99C7-$99D9` (19 bytes) - `TryAgainText`
- `$99E6-$99FF` (26 bytes) - `WinsDrawText`
- `$9A09-$9A34` (44 bytes) - `StopPushText`
- `$9AD7-$9BAF` (217 bytes) - `HurryGameEndText`
- `$9FA6-$9FAD` (8 bytes) - `BoardEdgeGraphic`
- `$A263-$A29F` (61 bytes) - `PlayerStartPositionTable`
- `$A3E9-$A3F8` (16 bytes) - `BoardFlipMaskTable`
- `$ABDB-$ABE2` (8 bytes) - `BoardStateBitsTable`
- `$AD3E-$AD53` (22 bytes) - `BoardCellWeightTable`
- `$AF00-$AF97` (152 bytes) - `RandomSeedTable`
- `$BCCE-$D6A3` (6614 bytes) - `BoardTilemapData`
- `$DA49-$DA60` (24 bytes) - `ControllerButtonNames`
- `$DD5F-$FFFF` (8865 bytes) - `LevelGraphicData`

## Build

```
Byte-identical ROM verified.
```