disasm/NROM/Golf (JU)/SPRITE_OBJECT_TABLE_AUDIT.md

Pass 1 sprite and object table audit

Scope

This audit covers tables consumed by ParseSpriteLayout at $CBEA and the per-hole object expansion path at $DE5E-$DF52. All addresses are CPU addresses in the fixed $C000-$FFFF PRG view.

A. Sprite-layout subsystem at $CC15-$CCA6

$CC15-$CC23: sprite-layout selection map

15 bytes. The caller indexes this table with a selection/state value and obtains one of five logical layout groups ($00-$04). This is an index-remap table, not sprite data.

$CC24-$CC30: standard layout pointer-low table

13 bytes:

74 89 9E B3 C8 DD C8 B3 F2 07 1C 31 46

These are low bytes of layout-list addresses. The matching high-byte table at $CC31-$CC3D is predominantly $CC, with $CD used when a list crosses into the next page.

Resolved standard pointers:

• $CC74
• $CC89
• $CC9E
• $CCB3
• $CCC8
• $CCDD
• $CCC8
• $CCB3
• $CCF2
• $CD07
• $CD1C
• $CD31
• $CD46

Repeated pointers are intentional mirroring of animation/layout states.

$CC31-$CC3D: standard layout pointer-high table

13 bytes paired one-for-one with $CC24-$CC30.

$CC3E-$CC43: alternate layout pointer-low table

6 bytes:

5B 70 9E 70 5B 74

$CC44-$CC49: alternate layout pointer-high table

6 bytes paired with $CC3E-$CC43.

Resolved alternate pointers:

• $CD5B
• $CD70
• $CC9E
• $CD70
• $CD5B
• $CC74

This table shares existing lists instead of duplicating them.

$CC4A-$CC5E: sprite X-offset table

21 signed/unsigned screen offsets indexed by the tile/list byte. Values repeat $00,$08,$10 patterns, matching three-column sprite construction.

$CC5F-$CC73: sprite Y-offset table

21 offsets indexed by the same tile/list byte. Values progress by eight pixels from $00 to $30, producing row-aligned sprite positions.

$CC74-$CD5A: terminated sprite-index lists

The pointer tables select variable-length byte lists in this range. Each byte is both:

• the OAM tile value, and
• an index into $CC4A and $CC5F for X/Y placement.

Each list terminates with $FF; the parser also has a hard 21-entry limit. The lists share suffixes and are deliberately referenced more than once.

$CD5B-$CD84 and later alternate lists

The alternate pointer table reaches $CD5B and $CD70. These are additional terminated tile-index lists using the same coordinate tables and OAM expansion format. Bytes beyond the last referenced terminator require separate consumer analysis before being named as part of this family.

B. Hole-object expansion tables at $E283-$E3DE

$E283-$E2A1: object span-end table

31 monotonically increasing values:

03 07 09 0B 0E 10 12 14 16 19 1B 1E 20 23 25 27 29 2B 2E 31 34 38 3A 3C 3E 40 43 45 47 49

The parser loads the selected value into $1D as the exclusive end index for a shape. The corresponding start index comes from the preceding entry at $E282,Y, making $E282/$E283 a compact prefix-boundary pair.

$E2A2-$E2EA: object CHR-tile sequence table

73 bytes. For each expanded OAM sprite, the parser reads one tile value from this table. Values are concentrated in $E0-$F2, matching the object/sprite CHR region.

$E2EB-$E333: object X-offset table

73 bytes paired with $E2A2-$E2EA. Values are mostly $00, $08, and $10, with a few compact adjustments. The parser adds each value to the record's base X byte.

$E334-$E37C: object Y-offset table

73 bytes paired with the tile and X-offset tables. The parser adds each value to the record's base Y byte.

Together these three 73-byte arrays form a structure-of-arrays representation:

• tile[index]
• x_offset[index]
• y_offset[index]

The span-end table maps an object selector to a contiguous slice of these parallel arrays.

$E37D-$E383: fixed setup span boundaries

Seven bytes:

00 03 06 0B 10 17 1E

The fixed setup parser uses a selector-derived range from the first two tables around $E37D/$E37E. These values are prefix boundaries for larger fixed sprite groups.

$E384-$E3A1: fixed setup X-offset table

30 bytes. Values are chiefly $00, $04, and $08, defining compact sprite clusters around a base position.

$E3A2-$E3BF: fixed setup tile table

30 bytes. Values are concentrated in $F5-$FC, identifying a separate CHR family from the variable object table.

$E3C0-$E3DD: fixed setup attribute table

30 bytes. Values are primarily $02 and $42, with $82 and $C2 variants. The high bits encode OAM flipping while the low bits select palette 2.

The fixed setup arrays are parallel and are consumed together when constructing OAM entries beginning near $0298.

$E3DE+: following data

$E3DE begins another sequence (08 08 00 ...) not indexed by either audited object expansion loop. It remains a separate table until its consumer is identified.

C. Per-hole object record format

After the fixed setup portion, ParseHoleObjectList consumes three-byte records:

• byte 0: object selector, or $FF terminator
• byte 1: base X adjustment
• byte 2: base Y adjustment

Selector n obtains a slice:

• start = span boundary n
• end = span boundary n + 1

Each slice element expands to one OAM entry using the tile/X/Y parallel arrays. Selectors whose expanded table index reaches $2B use OAM attribute $42; earlier entries use $02.

D. Classification conclusions

Confirmed structured data:

• $CC15-$CC23: layout-group remap
• $CC24-$CC49: split pointer tables
• $CC4A-$CC73: paired coordinate tables
• $CC74 onward: $FF-terminated sprite-index lists
• $E283-$E2A1: object span boundaries
• $E2A2-$E37C: three parallel 73-byte object expansion arrays
• $E37D-$E3DD: fixed setup boundaries and three parallel 30-byte arrays

No executable entry point exists inside these audited table ranges. Any legal 6502 opcode sequence found inside them is data and must be excluded from recursive code tracing.