processes the full wire boot incl. the downloaded PAZ/sfx module
ISA fixes, all derived from the toolchain's own .S<->.O pairs (AS860.ZIP:
OPTFLOAT/TRISTRIP/ZBUF32, plus DNC.O) and the firmware's linked COFF header:
- DATA_BASE = 0x1000 DEFINITIVE: VREND.MNG carries its original COFF header in
the file tail (.data vaddr 0x1000, .bss 0x1f940, entry 0xf0400000).
- Integer loads: even opcodes are register-indexed (EA = src2 + src1); op 4/5
size flag = instr bit0 (0 = ld.s 16-bit, 1 = ld.l 32-bit); ld.b/ld.s
sign-extend.
- Integer stores: st.s/st.l selected by offset bit0, same split-offset rule.
- FP loads/stores: FP register lives in the DEST field for both fld and fst
(fst does NOT use the integer split-store encoding); flag bits: bit0 =
auto-increment (base <- EA), bit1 1=.l/0=.d, bit2 = .q; .d/.q span register
pairs/quads. ~450 fld.d + ~300 fst.d were previously read/written 32-bit.
- bla (op 0x2d, was misdecoded as shrd): branch-on-LCC-and-add with the
sign-dependent LCC rule (src1<0 -> signed sum >= 0), so spent countdown
loops terminate. 335 bla instructions in the firmware.
- CORE ESCAPE (op 0x13): sub-op 1 = lock, 2 = calli, 7 = unlock. Previously
everything decoded as calli, so every spinlock acquire jumped to address 0 --
this was the phantom "exit stub" behind most earlier derails.
- f2b: IEEE overflow -> +/-inf instead of raising.
emu_main.py (new): runs the firmware's OWN main() (0xf0403f10) and feeds real
wire captures through a hooked dN_receive, so init/do_init/dispatch/handlers
all execute authentically. Provides the transputer-monitor environment
(processor id, DRAM region descriptors in the shared control block, sbrk/
shared-block seed slots) and hooks only the link primitives (bla busy-wait,
dN_mynode/dN_nodes/dN_receive/dN_send, putchar path, spinlocks, page allocator
+ virt->phys translator pending Tier-2 VRENDMON).
KEY DISCOVERY: the capture's args860/code860/data860/bss860 preamble is the
host DOWNLOADING an additional i860 module (the PAZ/sfx renderer layer, banner
"i860 50MHz") which installs the runtime handler tables and system objects.
Feeding it through the firmware's own handlers, the module loads and makes the
first IGC board-register writes. State: 834+ wire commands processed (module
download + init + create); first draw_scene sits at command 1568.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
CydandClaude Opus 4.8