Decode plane constants: fixed-point screen coordinates
edge_decode.py: the edge payloads' non-float words carry the plane constant/ vertex terms as .8 fixed-point screen coordinates (0x0000ec00 = 60416 = 236.0, a screen-x in the object's range), not IEEE floats -- which is why they weren't in the float list. Locates the last missing piece for edge reconstruction: A/B slope (float, verified 0.2%) + C (fixed-point coord). Readout §02 notes it. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
Claude Opus 4.8
@@ -136,6 +136,25 @@ reconstruct the coefficient (or just take the recognisable float planes), apply
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value at the tile origin (still to be located in the stream). Then it is a plain
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`igc_array.py` z-plane.
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## Plane constants are fixed-point screen coordinates
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The edge payloads' non-float words carry the plane's constant/vertex terms as
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**fixed-point screen coordinates** (`scratchpad/edge_decode.py`):
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```
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SEND(4) edge @0x08015000: 00000100 3e013991(A=0.1262) 0000ec00 00000000
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^ 0xec00 = 60416 = 236.0 * 256
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SEND(0x21) @0x08015260: … 0000ec00 (=236.0) 0000b53a (=181.2) …
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```
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`0x0000ec00 / 256 = 236.0` = a screen-x right in the object's x[126,255] range
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(first captured vertex was x≈237.5). So the constant term C is stored as a `.8`
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fixed-point coordinate (word/256), not an IEEE float — which is why it wasn't in
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the float list. SEND(0x29) is a long single-coefficient sweep (`-0.0626` repeated
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~30x across bit-planes = the coarse interpolant). This locates the last missing
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piece for edge reconstruction: A/B slope (float, verified 0.2%) + C (fixed-point
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coord). Remaining is pairing them per triangle + all-regions assembly.
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## What this changes
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The micro-code decode is now **extraction + bit-serial execution**, not blind
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@@ -0,0 +1,52 @@
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"""The edge payloads carry the plane's constant as FIXED-POINT screen coordinates,
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not floats (0x0000ec00 = 60416 = 236.0*256, a screen-x). Dump the edge SEND payloads
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reading each word as float AND as fixed-point (/256, /65536), and flag values that fall
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in the object's screen range x[126,255] y[0,93] — those are the C / vertex terms."""
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import sys, time, struct, pickle
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sys.path.insert(0, r'C:\VWE\TeslaRel410\emulator\firmware-decomp')
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import emu860, dis860, emu_main
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emu860.Mem.log = lambda self, *a, **k: None
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S = r'C:\Users\cyd\AppData\Local\Temp\claude\c--VWE-TeslaRel410\4e848c76-6e89-4034-8047-d8d491cb32d8\scratchpad'
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snap = pickle.load(open(S + r'\snapv2.pkl', 'rb'))
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r = emu_main.MainRunner(r'C:\VWE\TeslaRel410\dpl3-revive\patha\cap7.raw.bin', fw='capfw7', max_cmds=6000)
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cpu = r.cpu
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cpu.mem.pages = {k: bytearray(v) for k, v in snap['pages'].items()}
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cpu.ctrl.clear(); cpu.ctrl.update(snap['ctrl'])
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cpu.r = list(snap['r']); cpu.f = list(snap['f']); cpu.cr = dict(snap['cr']); cpu.pc = snap['pc']
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cpu._apipe = list(snap['apipe']); cpu._mpipe = list(snap['mpipe']); cpu._fp_pipes()
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cpu._lpipe = list(snap['lpipe']); cpu._gpipe = list(snap['gpipe'])
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cpu._kr, cpu._ki, cpu._t = snap['kr'], snap['ki'], snap['t']
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cpu.lcc = snap['lcc']; r.qi = snap['qi']; r.heap = list(snap['heap'])
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t0 = time.time(); startq = r.qi
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while time.time() - t0 < 60:
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if r.qi >= startq + 2: break
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h = r.hooks.get(cpu.pc)
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if h:
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if h(cpu) == 'done': break
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continue
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if not cpu.step(): break
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def rw(a): return cpu.mem.r32(a & 0xffffffff)
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def asf(w): return struct.unpack('<f', struct.pack('<I', w))[0]
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def flags(w):
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out = []
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f = asf(w); e = (w >> 23) & 0xff
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if 1e-4 < abs(f) < 1e6 and 1 < e < 254:
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out.append("f=%.5g" % f)
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for div, tag in [(256.0, '/256'), (65536.0, '/65536')]:
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v = w / div
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if 0 < v < 900: # plausible screen coord
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out.append("%s=%.2f" % (tag, v))
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lo = w & 0xffff; hi = (w >> 16) & 0xffff
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for name, val in [('lo', lo), ('hi', hi)]:
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if 100 < val < 60000:
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vv = val / 256.0
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if 0 < vv < 600: out.append("%s/256=%.1f" % (name, vv))
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return " ".join(out)
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for base, n, tag in [(0x08015000, 4, 'SEND(4) edge'), (0x08015260, 0x21, 'SEND(0x21)'),
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(0x08015380, 0x29, 'SEND(0x29)')]:
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print("\n===== %s @ %#010x =====" % (tag, base))
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for i in range(n):
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w = rw(base + i * 4)
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print(" +%03x %08x %s" % (i * 4, w, flags(w)))
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@@ -269,8 +269,9 @@
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bit-plane, exactly how a bit-serial adder holds a number. And the recovered values are the
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object's own geometry: a payload edge coefficient (<span class="mono">0.12527</span>) lands on
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the edge normal computed from the captured vertices (<span class="mono">0.12555</span>) to
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<b>0.2%</b>. The coefficients feeding the array simulator (§05) are
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<b>the ones the hardware actually shipped</b>.</p>
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<b>0.2%</b>. The plane <b>constants</b> sit alongside as fixed-point screen coordinates
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(<span class="mono">0x0000ec00 = 236.0</span>, a vertex x). The coefficients feeding the array
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simulator (§05) are <b>the ones the hardware actually shipped</b>.</p>
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</section>
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<section>
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