SBlk body head: the DAW size, stored twice

Picked sound_bank rather than tie, where three discriminators have now come back negative and a fourth would be guesswork. The body after the 24-byte head opens with twelve words. Six are settled across all 27 levels: word value note 0 varies per level not identified; 27 distinct 1 60 constant 2 varies per level not identified; 23 distinct 3 0 constant 4 daw_size == the header's daw_size, exactly 5 daw_size the same value again 6,7,8 0 constant 9 127 constant 10 1 constant 11 0 constant Level 0's words 4 and 5 are both 1,482,000, and daw_size is 1,482,000. THE POINTER THAT WAS NOT ONE Words 4 and 5 were briefly recorded as pointers into the DAW region. They are not. The test that promoted them was "does this value fall inside [daw_offset, daw_offset + daw_size)" -- and the DAW region is ~1.5 MB starting near the front of a ~1.5 MB extent, so almost any plausible 32-bit word lands inside it. 1,482,000 is merely just under the top of exactly that range. A range test is not an identification. What survives is EQUALITY with daw_size, exact on all 27 levels and asserted, which is a claim that can fail rather than one that is almost always true. That is the fourth time this session a plausible reading of a single number has had to be withdrawn for something falsifiable: the 305x class-ID slot, the UV-corner texcoords, the VIF code word, and now this. The pattern is consistent enough to be worth stating as a rule -- a test that passes almost always is measuring the shape of the data, not a property of it. Word 0 gets one note: levels 1 and 4 hold 13,042,052 and 13,042,054, two apart, while their daw_sizes differ by 63,504. Whatever it is, it is not a size. The remainder of the SBlk body -- the per-sound record table -- is still undecoded, so sound_bank stays open. A SBlkBodyHead struct carries the twelve words with the constants asserted in its docs. 259 tests.
2026-10-14 03:06:36 +02:00
parent ec433e3341
commit 4ca0308499
3 changed files with 146 additions and 0 deletions
@@ -2865,3 +2865,45 @@ So: on a flat record, `i16[4]`/`i16[5]` are **not identified**, and the texcoord
 slot of a tie vertex is unknown. What survives from the original section is the
 boundary work -- `vert_ofs + vert_size + scissor_size` is the region length -- and
 the LOD1/LOD2 sharing result, which is stride-insensitive.
+
+
+## The `SBlk` body head: the DAW size, twice
+
+The body after the 24-byte head opens with twelve words, and six of them are
+settled across all 27 levels:
+
+    word   value                 note
+    0      varies per level      not identified; 27 distinct
+    1      60                    constant
+    2      varies per level      not identified; 23 distinct
+    3      0                     constant
+    4      daw_size              == the header's daw_size, exactly
+    5      daw_size              the same value again
+    6      0                     constant
+    7      0                     constant
+    8      0                     constant
+    9      127                   constant
+    10     1                     constant
+    11     0                     constant
+
+Level 0's words 4 and 5 are both 1,482,000, and `daw_size` is 1,482,000.
+
+### The pointer that was not one
+
+Words 4 and 5 were briefly recorded as pointers into the DAW region. They are not.
+The test that promoted them was "does this value fall inside
+`[daw_offset, daw_offset + daw_size)`", and the DAW region is ~1.5 MB starting
+near the front of a ~1.5 MB extent -- so almost any plausible 32-bit word lands in
+it, and 1,482,000 is just under the top of exactly that range.
+
+**A range test is not an identification.** The claim that survives is *equality
+with `daw_size`*, which is exact on all 27 levels and is asserted. That is the
+fourth time in this session that a plausible reading of one number has had to be
+withdrawn in favour of a claim that can fail.
+
+Word 0 is worth one note: levels 1 and 4 hold 13,042,052 and 13,042,054, two
+apart, while their `daw_size`s differ by 63,504. Whatever it is, it is not a
+size.
+
+Asserted in `sound_bank_sblk_body_head_carries_the_daw_size_twice`. The remainder
+of the body -- a per-sound record table -- is still undecoded.