# Stack-Up (JU)

## 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: 10,586 / 32,768 bytes (32.3%).
`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 | $81AD |
| RESET vector | $8100 |
| IRQ vector | $81E6 |

## Power-on flow

RESET enters at `$8100`:

    cld                            ; CPU:$8100 PRG:0100  D8
    sei                            ; CPU:$8101 PRG:0101  78
    ldx #$00                       ; CPU:$8102 PRG:0102  A2 00
    stx PPUCTRL                    ; CPU:$8104 PRG:0104  8E 00 20
    stx PPUMASK                    ; CPU:$8107 PRG:0107  8E 01 20
    lda PPUSTATUS                  ; CPU:$810A PRG:010A  AD 02 20
    bpl Reset_OnNonnegative        ; CPU:$810D PRG:010D  10 FB
    dex                            ; CPU:$810F PRG:010F  CA
    txs                            ; CPU:$8110 PRG:0110  9A
    ldx Zp2F                       ; CPU:$8111 PRG:0111  A6 2F
    ldy #$07                       ; CPU:$8113 PRG:0113  A0 07
    sty Zp01                       ; CPU:$8115 PRG:0115  84 01

NMI handler at `$81AD`:

    pha                            ; CPU:$81AD PRG:01AD  48
    txa                            ; CPU:$81AE PRG:01AE  8A
    pha                            ; CPU:$81AF PRG:01AF  48
    tya                            ; CPU:$81B0 PRG:01B0  98
    pha                            ; CPU:$81B1 PRG:01B1  48
    lda #$00                       ; CPU:$81B2 PRG:01B2  A9 00
    sta OAMADDR                    ; CPU:$81B4 PRG:01B4  8D 03 20
    lda #$02                       ; CPU:$81B7 PRG:01B7  A9 02

## Data-table inventory (Pass 3)

- `$8000-$80FF` (256 bytes) - `CopyrightText`
- `$82EA-$8309` (32 bytes) - `PlayerNameTable`
- `$8827-$8875` (79 bytes) - `LevelHandlerPointerTable`
- `$8BFD-$8C04` (8 bytes) - `BlockHeightTable`
- `$8C3A-$8C69` (48 bytes) - `BlockPatternTable`
- `$8FCF-$8FE3` (21 bytes) - `BlockShapeTable`
- `$9017-$9066` (80 bytes) - `BlockLayoutTable`
- `$9090-$9317` (648 bytes) - `BlockPlacementCode`
- `$9344-$935D` (26 bytes) - `BlockAttributeTable`
- `$943F-$99FD` (1471 bytes) - `BlockPointerTable`
- `$9A2C-$9A96` (107 bytes) - `BlockColorTable`
- `$9AB4-$9AC7` (20 bytes) - `BlockCountTable`
- `$9C52-$9C5E` (13 bytes) - `BlockSizeTable`

## Build

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