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Ten more Copilot inline comments, all addressing test encoding bugs
that were masquerading as emulator bugs. Net effect: +13 tests
PASS, two of the three "real bugs" I documented in the previous
README turned out to be my wrong test code.
## Blitter command bit positions (the big one)
Copilot caught that I had the entire blitter command encoding wrong.
Per src/tom/blitter.c:113-145:
bit 0 = SRCEN (was correct)
bit 3 = DSTEN (I was using $20, which is DSTWRZ)
bit 11 = DSTA2
bit 12 = GOURD
bits 21-24 = LFU function (I had been using bits 14|15 = $C000,
which are unused "ity" bits, not LFU at all)
bit 26 = BCOMPEN (I'd been encoding $0200)
bit 28 = BKGWREN (I'd been encoding $0100)
Fixed across 17 affected files:
copy_simple/pix8/pix32, multiline_copy: $0001C000 -> $01800001
(SRCEN | LFU=$C)
lfu_passthrough_src: $0001C000 -> $01800001
lfu_and / lfu_or / lfu_xor: ...0021 -> ...0009 (DSTEN $08, not $20)
bcompen_basic: $0001C201 -> $05800001
bkgwren_test: $0001C121 -> $19800009
dsta2_swap: $0001C801 -> $01800801
gourd_basic: $0001D001 -> $01801001
many_blits + bus/blitter_back_to_back + bus/cpu_blitter_concurrent:
$0001C000 -> $01800001
Result: 13 of the 14 SRC-reading blitter tests now PASS. The
"blitter source-data routing bug" I documented as a real emulator
issue did not exist -- it was my wrong encoding all along.
## JERRY PIT writable vs readable addresses
Copilot caught that I was using $F10036/$F10038 to *configure* the
JERRY PIT, but per src/jerry/jerry.c those addresses are readback
aliases. The writable setup regs (which actually call
JERRYResetPIT1) are at $F10000/$F10002.
Fixed:
- jerry_pit_irq.s -- writes JPIT1/JPIT2 at $F10000/$F10002 now;
test moved NOT-RUN-YET -> PASS, perf counter shows
timing_jerry_irqs=7,813,748 IRQs fired in the test window.
- jerry_pit_setup.s -- rewritten to write via $F10000/$F10002
then read back via $F10036/$F10038 to verify the round-trip;
test moved FAIL -> PASS.
## tom_int1_readback now actually probes the write-only behavior
Copilot pointed out my test only wrote high-byte clear bits ($0F00)
and never wrote a low-byte enable mask, so the documented
"enable bits are write-only" semantic was never exercised. Now
writes a real low-byte enable mask ($000F) before reading back.
## unaligned_word now actually does a misaligned access
Copilot noted the actual misaligned load was commented out, so the
test could only validate that vector-3 install doesn't crash. Now
performs `move.w (a4),d5` with a4 holding an odd address, traps to
vector 3, the handler bumps a flag and steps past the offending
instruction via stack-frame manipulation.
## dsp_mac_accumulator marked as deliberate FAIL placeholder
Copilot pointed out it was a NOP loop reporting PASS, which would
mask future MAC regressions. Reframed to ACID_FAIL with detail=99
so it's visible in the failing-tests column as "test not yet
implemented".
## Final status
Before this round: 54/72 PASS
After this round: 67/72 PASS (+13)
Remaining FAILs (5):
divl_zero_traps REAL emulator bug -- DIVS.L #0 doesn't
trap. Worth focused investigation.
bcompen_basic Test encoding still incomplete (got
source byte where we wanted pattern fg).
copy_simple Partial copy -- detail=3 (3rd longword
wrong, others right). Test setup needs
a step / pitch tweak.
pattern_fill PATDSEL alone insufficient; need more
flags to land pattern in dest.
dsp_mac_accumulator Deliberate placeholder.
README updated with the new pass numbers and a "How we got from 33%
to 93% in one review round" section to record the lessons:
1. TOM_INT1 byte order: enable mask is the LOW byte, not high
2. Blitter cmd bit positions: SRCEN=bit 0, DSTEN=bit 3,
LFU=bits 21..24 (not what the original docs comment suggested)
3. JERRY PIT setup at $F10000/$F10002, readback at $F10036/$F10038
Co-Authored-By: Claude Opus 4.7 <[email protected]>
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