AnachronautandClaude Opus 5
dcb331c151
Programs/CosmOS/Assembler/ is an assembler written in SplitBit assembly. It
runs under CosmOS, reads source off a SplitBit disk, and writes a binary back
to it with no host involved anywhere:
> run Asm.sbx hello.asm
wrote hello.bin: program 17, data 14, labels 2
THE ACCEPTANCE TEST IS THE BYTES. Tests/native.sh assembles Programs/hello.asm
both ways and compares the two files byte for byte, then runs the one the
machine built. "It ran" and "the sizes look right" both pass for a binary with
a label one byte out, which is a program that jumps into the middle of an
instruction - so the only honest test is the one SplitDisk and sbfs.asm
already work under: two implementations of one written specification, each
checking the other. The files are identical and the result prints Hello,
World! in 70 cycles.
hello.asm is the target because it is the oldest program in the repository.
The first thing this machine ever ran is now the first thing it assembles for
itself.
TWO PASSES OVER STREAMED SOURCE. The C assembler reads every token of every
file into one array; that cannot port, because cosmos.asm alone is 56,047
bytes against 64K of Data Memory. The native one streams through a 256 byte
window, twice, and keeps only the label table between the passes. Two passes
suffice because every length is known without resolving anything - an
instruction's from its shape, a value's is one, a string's is its characters
and a zero - so the first pass fixes every address and the second never needs
a fixup list. A forward reference stops being a special case and becomes the
reason there are two passes at all.
The parts, each checked before anything was built on it:
source.asm characters out of a file of any size, with a line number
token.asm tokens out of characters, one character of lookahead
classify.asm what a token is, in the C assembler's order, which IS the
language: keyword, instruction, value, string, label
labels.asm names packed in an arena, four bytes of index each
numbers.asm sixteen bit arithmetic, since sbfs.asm's cannot be reached
table.asm the instruction set, generated by the same script the
monitor's copy is, and now BOTH are checked by docs.sh
readTest.asm and tokenTest.asm check the reader and the tokenizer on their
own, recorded as cosmosSource and cosmosTokens. A wrong classification does
not produce a wrong byte somewhere obvious; it produces a right looking
program of the wrong length, so it is worth catching where it happens.
WHAT IT REFUSES: #Include, #Base, #Align, #Reserve and #Vectors are refused
by name rather than ignored. Skipping a directive would produce a file that
looked right and was the wrong length, which is the worst thing an assembler
can do.
Two traps worth recording, both already known to this project and both hit
again: CALL restores A, B and DP0-DP2, so three routines returning an answer
in A had it undone by their own return; and numStep works on DP0, so three
sites that set DP1 left a pointer that never advanced.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
91 lines
3.3 KiB
Bash
Executable File
91 lines
3.3 KiB
Bash
Executable File
#!/usr/bin/env bash
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# Checks the assembler that runs on SplitBit against the one that runs on the host.
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#
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# THE ONLY HONEST TEST OF AN ASSEMBLER IS THE BYTES IT PRODUCES. "It ran" and "the sizes
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# look right" both pass for a binary with a label one byte out, which is a program that
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# jumps into the middle of an instruction. So this assembles the same source both ways and
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# compares the two files byte for byte, the same discipline SplitDisk and sbfs.asm work
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# under: two implementations of one written specification, each one checking the other.
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#
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# Then it runs what the machine built, because a file that matches and does not work would
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# mean both assemblers were wrong together.
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#
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# Written by Anachronaut
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set -u
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ROOT="$(cd "$(dirname "$0")/.." && pwd)"
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WORK="$ROOT/Tests/build/native"
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ASM="$ROOT/Assembler"
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TOOL="$ROOT/SplitDisk"
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EMU="$ROOT/SplitBit"
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PASS=0
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FAIL=0
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FAILED_NAMES=()
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check() {
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local name="$1"
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shift
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if "$@"; then
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printf ' [ok ] %-22s %s\n' "$name" "${REPORT:-}"
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PASS=$((PASS + 1))
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else
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printf ' [FAIL] %-22s %s\n' "$name" "${REPORT:-}"
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FAIL=$((FAIL + 1))
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FAILED_NAMES+=("$name")
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fi
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REPORT=""
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}
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for tool in "$ASM" "$TOOL" "$EMU"; do
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[ -x "$tool" ] || { echo "$(basename "$tool") is not built."; exit 1; }
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done
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rm -rf "$WORK"
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mkdir -p "$WORK"
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# The system it runs under, and the assembler itself, both built by the host assembler.
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# Bootstrapping has to start somewhere, and this is the last place it does.
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"$ASM" -I "$ROOT/Programs/Libraries" -I "$ROOT/Programs/CosmOS/Source" \
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-o "$WORK/cosmos.bin" "$ROOT/Programs/CosmOS/Source/cosmos.asm" >/dev/null || exit 1
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"$ASM" -I "$ROOT/Programs/CosmOS/Source" -I "$ROOT/Programs/CosmOS/Assembler" \
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-o "$WORK/Asm.sbx" "$ROOT/Programs/CosmOS/Assembler/Asm.asm" >/dev/null || exit 1
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"$TOOL" format "$WORK/native.img" 2048 4 >/dev/null
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"$TOOL" put "$WORK/native.img" "$ROOT/Programs/hello.asm" hello.asm >/dev/null
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"$TOOL" put "$WORK/native.img" "$WORK/Asm.sbx" Asm.sbx >/dev/null
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printf 'load Asm.sbx\nrun hello.asm\nexit\n' \
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| "$EMU" --fast --cycles 50000000 -D "$WORK/native.img" "$WORK/cosmos.bin" \
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> "$WORK/session.txt" 2>&1
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# ---- It got as far as writing something ----
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check "it wrote a file" grep -q "wrote hello.bin" "$WORK/session.txt"
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# ---- And the file is the one the host assembler makes ----
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"$ASM" -o "$WORK/reference.bin" "$ROOT/Programs/hello.asm" >/dev/null
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"$TOOL" get "$WORK/native.img" hello.bin "$WORK/native.bin" >/dev/null 2>&1
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if [ -f "$WORK/native.bin" ]; then
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REPORT="$(wc -c < "$WORK/native.bin" | tr -d ' ') bytes"
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fi
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check "byte for byte" cmp -s "$WORK/native.bin" "$WORK/reference.bin"
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# ---- And what it built actually runs ----
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"$EMU" --fast --cycles 100000 "$WORK/native.bin" > "$WORK/ran.txt" 2>&1
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check "and it runs" grep -q "^Hello, World!$" "$WORK/ran.txt"
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# ---- The report it printed says what it did ----
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REPORT="$(grep -o 'program [0-9]*, data [0-9]*, labels [0-9]*' "$WORK/session.txt" || true)"
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check "it counted right" grep -q "program 17, data 14, labels 2" "$WORK/session.txt"
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echo
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if [ "$FAIL" -eq 0 ]; then
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echo "All $PASS native assembler checks passed."
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else
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echo "$PASS passed, $FAIL failed: ${FAILED_NAMES[*]}"
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echo
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echo "The session was:"
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sed 's/^/ /' "$WORK/session.txt"
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exit 1
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fi
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