summary_val-conversions.md 1.3 KB
Step: VAL conversions (LONGINT/REAL) + long→int narrowing
Tag v3-val-conversions. Suite 148/148; fixpoint OK
(image 2,320,770 bytes).
What
VAL now covers the numeric conversions V3 lacked:
| From → To | Codegen |
|---|---|
INTEGER → LONGINT |
extsw (sign-extend) |
LONGINT → INTEGER |
copy w (low 32 bits) |
INTEGER → REAL |
swtof |
LONGINT → REAL |
sltof |
REAL → INTEGER |
dtosi (truncate toward zero) |
REAL → LONGINT |
dtosi |
(Ordinal↔ordinal, pointer↔pointer and REAL↔REAL were already allowed.)
New QbeGen helpers: NarrowLong, ConvRI, ConvRL, ConvLR
(alongside the existing WidenLong/ConvIR).
Payoff
Conversions is simplified: StrToInt/StrToCard now accumulate in
a LONGINT and simply range-check, then narrow with VAL(INTEGER, v)
/ VAL(CARDINAL, v) — the previous "detect overflow before the 32-bit
wrap" hand-guard is gone.
Tests
t_valconv.mod (15): int→long→int round-trip, int→real, real→int
truncation, long→real. ConvProg/ConvResultsProg still pass with
the rewritten Conversions.
Files
compiler/src/QbeGen.def/.mod (NarrowLong/ConvRI/ConvRL/
ConvLR), compiler/src/M2.atg (VAL action),
stdlib/conversions.mod, compiler/tests/t_valconv.mod,
compiler/run_tests.sh, docs/features.md.