rea/website/evidence/dx-ball-sound-pan.md

DX-Ball sound-pan evidence

The website presents one function from the English DX-Ball 1.07 Windows i386 executable. Project progress and validation claims are pinned to reconstruction commit a55dca27ec0a07018c1b2c95ae2be027f7d8c3c4 (7 October 2026).

Artifact and provider

• Target: DXBALL.EXE, 158,208 bytes, PE i386.
• SHA-256: 756da1ba09edce716d5bf8770320ca0d5ed4e525672b6bb605b9bdb4b88972ba.
• Function: 0x406400 through 0x40643e, inclusive, 63 bytes.
• Recorded analysis: REA 4.1.0, Ghidra 12.1.4, Linux x64 host.
• Pan dossier: ev_ddca58134d89a2eb0aba5bf5694bb06ce7b5cb28aac0eb847891506244e70490.
• Caller dossier: ev_d09866ff22dc07f3ac28ef1d992c5876c1e58e1796dbe0f0c5c2814544aa27eb.
• Constants read: ev_6a56fda997bcda2df677257601da0174ff8041d44c8c83c48356df31edf0f7ae.
• Scale read: ev_64752f4ecf1ec74384ce01083c21fcfffb716931f6c31a7dac351a136df7979e.

The website update reused the matching saved REA results and verified the local target digest. It did not start a new provider session or repeat the project's execution/compiler checks. Complete dossiers, snapshots, the original executable and compiler products remain in the reconstruction project.

Observations and interpretation

Saved observation	Interpretation used by the reconstruction
Stack load from [EBP+8], then FILD	An integer parameter, named x
Brick-hit caller multiplies its coordinate by 30, adds 20, pushes EAX	The input is a brick's horizontal screen position
FMUL [0x420068]; byte read decodes to 1.5625	pan = pan * 1.5625
FSUB [0x420070]; byte read decodes to 500.0	pan = pan - 500.0
FMUL [0x4210a0]; initial double is 1.0	A stored scale, named dxball_pan_scale
Call to __ftol at 0x41678c	Convert the calculation to an integer

The names dxball_screen_pan, x and dxball_pan_scale belong to the maintained source. The executable's instruction view supplies addresses and operations. The original decompiler result reports FUN_00406400(void) and a conversion call, omitting the stack input and x87 expression. The website's pseudocode excerpt preserves that body and omits only its leading provider warning/comment and blank lines.

Displayed REA requests

The page shows the actual tool names with compact input excerpts:

• analyze_function at procedure 0x406400 returns the pan dossier, including its instruction view and the caller entry at 0x411f40.
• analyze_function at procedure 0x411f40 returns the brick-hit dossier. The visible caller excerpt preserves the ADD/PUSH/CALL instructions verbatim; the full supporting excerpt also shows the preceding ×30 calculation.
• read_bytes at 0x420068, length 16, returns 000000000000f93f0000000000407f40.
• read_bytes at 0x4210a0, length 8, returns 000000000000f03f.

The page splits the first byte read into two eight-byte values and shows their little-endian double interpretations beside the observed hex. These are decoded values, not additional fields in the raw REA result. Query groups present the reasoning sequence rather than reproducing an entire chronological session. Provider details are recorded here; the product narrative uses REA to describe the CLI/MCP operations the agent called.

Complete recorded instruction listing

Transcribed verbatim from the pan dossier's normalized assembly facet:

0x406400: PUSH EBP
0x406401: MOV EBP, ESP
0x406403: SUB ESP, 0xc
0x406406: PUSH EBX
0x406407: PUSH ESI
0x406408: PUSH EDI
0x406409: MOV EAX, dword ptr [EBP + 0x8]
0x40640c: MOV dword ptr [EBP + -0xc], EAX
0x40640f: FILD dword ptr [EBP + -0xc]
0x406412: FST double ptr [EBP + -0x8]
0x406415: FMUL double ptr [0x00420068]
0x40641b: FST double ptr [EBP + -0x8]
0x40641e: FSUB double ptr [0x00420070]
0x406424: FST double ptr [EBP + -0x8]
0x406427: FMUL double ptr [0x004210a0]
0x40642d: FST double ptr [EBP + -0x8]
0x406430: CALL 0x0041678c
0x406435: JMP 0x0040643a
0x40643a: POP EDI
0x40643b: POP ESI
0x40643c: POP EBX
0x40643d: LEAVE
0x40643e: RET

The interactive website excerpt selects eight instructions from this listing. It omits setup/cleanup, intermediate FST stores and the epilogue jump to keep the calculation visible. The expandable listing retains all 23 instructions. Copying the C panel copies the complete maintained function, including its signature, declaration and return.

Validation scope

The reconstruction project's recorded checks establish:

• 3,205 direct original-x86 differential cases: integer positions 0–640 at scales 0, 0.5, 1, 20 and −1.
• 63 matching bytes for the complete VC4.0-compiled function, after applying every reviewed relocation and checking referenced constants.

These claims apply to this function at the linked checkpoint. The figure shows execution comparison and compiler replay as separate branches. Game-level integration remains a separate project task.

Public sources

• Gameplay observations and Evidence IDs
• Maintained function
• Semantic acceptance ledger
• Complete function units and relocation mappings
• Compiler replay method