# V3 step 6.2 — true 64-bit LONGINT/LONGCARD (done 2026-09-22)

`LONGINT`/`LONGCARD` were aliases of the 32-bit int family; now they
are real 64-bit values (QBE `l`). Suite 100/100. LL(1)-clean, zero
gm2 warnings.

## Types (SymTab)

- New form `FLong` and descriptor `dLong`; `LONGINT`/`LONGCARD`
  predefine to it. New class `ClLong` (13).
- `IsLongFamily`; `TypeSize(FLong) = 8`.
- Rules: `ArithCheck` promotes long/long and long/int → `dLong`;
  `UnaryCheck` long → `dLong`; `Assignable` allows int → long
  (widening) but not long → int; `EqCheck`/`OrdCheck` accept long
  pairs.

## Backend (QbeGen)

- `ResClass(ClLong) = "l"`; `ElemSize`/`ElemLoad`/`ElemStore` treat
  long as 8-byte (`loadl`/`storel`); `AllocLocal` gives long locals
  an 8-byte slot; module-level long data emits `{ l 0 }`.
- `LoadLong`/`StoreLong` (same-scope, up-level, and global paths);
  `WidenLong` (`extsw`, INTEGER → LONGINT); `CmpLong`
  (`ceql`/`cnel`/`csltl`/`cslel`/`csgtl`/`csgel`).

## Grammar

- `Design` loads long vars via `LoadLong`; assignment stores via
  `StoreLong` and widens int sources; `SimExpr`/`Term` use `Op3L`
  (`add`/`sub`/`mul`/`div`/`rem` at `l` width) and widen int
  operands; `Expr` uses `CmpLong` and widens int operands; `VarDecl`
  accepts `ClLong`.

## Test

`t_long` → 42: `1_000_000 * 1_000_000` (= 10^12, past 32 bits),
divide back, compare, and `+5`. Image shows `extsw`, `=l mul/div`,
`ceql`/`csgtl`.

## Notes / deferred

- `FOR` bounds stay integer-family (`IsIntFamily` excludes long);
  the loop variable must be INTEGER/CARDINAL.
- REAL ↔ LONGINT conversions and long→int narrowing (`TRUNC`/`VAL`)
  are not yet wired — assignment long → int is 210.
- System call argument widths: only integer-sized args are passed to
  libc today (sizes/counts are small in current use).