From 0f9ff000c43c7178fc12bd31a5cba95d1318bbbc Mon Sep 17 00:00:00 2001 From: Cyd Date: Thu, 16 Jul 2026 16:39:25 -0500 Subject: [PATCH] Decode plane constants: fixed-point screen coordinates MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 --- .../firmware-decomp/MICROCODE-DECODE-NOTES.md | 19 +++++++ emulator/firmware-decomp/edge_decode.py | 52 +++++++++++++++++++ emulator/firmware-decomp/render-readout.html | 5 +- 3 files changed, 74 insertions(+), 2 deletions(-) create mode 100644 emulator/firmware-decomp/edge_decode.py diff --git a/emulator/firmware-decomp/MICROCODE-DECODE-NOTES.md b/emulator/firmware-decomp/MICROCODE-DECODE-NOTES.md index a1e40cf..af67cbb 100644 --- a/emulator/firmware-decomp/MICROCODE-DECODE-NOTES.md +++ b/emulator/firmware-decomp/MICROCODE-DECODE-NOTES.md @@ -136,6 +136,25 @@ reconstruct the coefficient (or just take the recognisable float planes), apply value at the tile origin (still to be located in the stream). Then it is a plain `igc_array.py` z-plane. +## Plane constants are fixed-point screen coordinates + +The edge payloads' non-float words carry the plane's constant/vertex terms as +**fixed-point screen coordinates** (`scratchpad/edge_decode.py`): + +``` +SEND(4) edge @0x08015000: 00000100 3e013991(A=0.1262) 0000ec00 00000000 + ^ 0xec00 = 60416 = 236.0 * 256 +SEND(0x21) @0x08015260: … 0000ec00 (=236.0) 0000b53a (=181.2) … +``` + +`0x0000ec00 / 256 = 236.0` = a screen-x right in the object's x[126,255] range +(first captured vertex was x≈237.5). So the constant term C is stored as a `.8` +fixed-point coordinate (word/256), not an IEEE float — which is why it wasn't in +the float list. SEND(0x29) is a long single-coefficient sweep (`-0.0626` repeated +~30x across bit-planes = the coarse interpolant). This locates the last missing +piece for edge reconstruction: A/B slope (float, verified 0.2%) + C (fixed-point +coord). Remaining is pairing them per triangle + all-regions assembly. + ## What this changes The micro-code decode is now **extraction + bit-serial execution**, not blind diff --git a/emulator/firmware-decomp/edge_decode.py b/emulator/firmware-decomp/edge_decode.py new file mode 100644 index 0000000..7a37d02 --- /dev/null +++ b/emulator/firmware-decomp/edge_decode.py @@ -0,0 +1,52 @@ +"""The edge payloads carry the plane's constant as FIXED-POINT screen coordinates, +not floats (0x0000ec00 = 60416 = 236.0*256, a screen-x). Dump the edge SEND payloads +reading each word as float AND as fixed-point (/256, /65536), and flag values that fall +in the object's screen range x[126,255] y[0,93] — those are the C / vertex terms.""" +import sys, time, struct, pickle +sys.path.insert(0, r'C:\VWE\TeslaRel410\emulator\firmware-decomp') +import emu860, dis860, emu_main +emu860.Mem.log = lambda self, *a, **k: None +S = r'C:\Users\cyd\AppData\Local\Temp\claude\c--VWE-TeslaRel410\4e848c76-6e89-4034-8047-d8d491cb32d8\scratchpad' +snap = pickle.load(open(S + r'\snapv2.pkl', 'rb')) +r = emu_main.MainRunner(r'C:\VWE\TeslaRel410\dpl3-revive\patha\cap7.raw.bin', fw='capfw7', max_cmds=6000) +cpu = r.cpu +cpu.mem.pages = {k: bytearray(v) for k, v in snap['pages'].items()} +cpu.ctrl.clear(); cpu.ctrl.update(snap['ctrl']) +cpu.r = list(snap['r']); cpu.f = list(snap['f']); cpu.cr = dict(snap['cr']); cpu.pc = snap['pc'] +cpu._apipe = list(snap['apipe']); cpu._mpipe = list(snap['mpipe']); cpu._fp_pipes() +cpu._lpipe = list(snap['lpipe']); cpu._gpipe = list(snap['gpipe']) +cpu._kr, cpu._ki, cpu._t = snap['kr'], snap['ki'], snap['t'] +cpu.lcc = snap['lcc']; r.qi = snap['qi']; r.heap = list(snap['heap']) +t0 = time.time(); startq = r.qi +while time.time() - t0 < 60: + if r.qi >= startq + 2: break + h = r.hooks.get(cpu.pc) + if h: + if h(cpu) == 'done': break + continue + if not cpu.step(): break +def rw(a): return cpu.mem.r32(a & 0xffffffff) +def asf(w): return struct.unpack('> 23) & 0xff + if 1e-4 < abs(f) < 1e6 and 1 < e < 254: + out.append("f=%.5g" % f) + for div, tag in [(256.0, '/256'), (65536.0, '/65536')]: + v = w / div + if 0 < v < 900: # plausible screen coord + out.append("%s=%.2f" % (tag, v)) + lo = w & 0xffff; hi = (w >> 16) & 0xffff + for name, val in [('lo', lo), ('hi', hi)]: + if 100 < val < 60000: + vv = val / 256.0 + if 0 < vv < 600: out.append("%s/256=%.1f" % (name, vv)) + return " ".join(out) + +for base, n, tag in [(0x08015000, 4, 'SEND(4) edge'), (0x08015260, 0x21, 'SEND(0x21)'), + (0x08015380, 0x29, 'SEND(0x29)')]: + print("\n===== %s @ %#010x =====" % (tag, base)) + for i in range(n): + w = rw(base + i * 4) + print(" +%03x %08x %s" % (i * 4, w, flags(w))) diff --git a/emulator/firmware-decomp/render-readout.html b/emulator/firmware-decomp/render-readout.html index b7add28..531bedb 100644 --- a/emulator/firmware-decomp/render-readout.html +++ b/emulator/firmware-decomp/render-readout.html @@ -269,8 +269,9 @@ bit-plane, exactly how a bit-serial adder holds a number. And the recovered values are the object's own geometry: a payload edge coefficient (0.12527) lands on the edge normal computed from the captured vertices (0.12555) to - 0.2%. The coefficients feeding the array simulator (§05) are - the ones the hardware actually shipped.

+ 0.2%. The plane constants sit alongside as fixed-point screen coordinates + (0x0000ec00 = 236.0, a vertex x). The coefficients feeding the array + simulator (§05) are the ones the hardware actually shipped.