# Bit-precise Integer Types

Background
----------

C23 (see [draft][1]) is introducing signed and unsigned `_BitInt(N)` types.
These can express much larger precision than standard or
even extended integral types, can have different ABI for
argument passing/returning valuess from normal integers.

While I guess one could represent those with

    DW_AT_encoding  DW_ATE_signed   // or DW_ATE_unsigned
    DW_AT_bit_size  238
    DW_AT_byte_size 32
    DW_AT_name      "_BitInt(238)"

requiring parsing of the `DW_AT_name` and special-casing
`_BitInt` used in there for the ABI handling would be awkward.
So, I think it is better to use new `DW_ATE_*` values for this.

Proposed Changes
----------------

Table 5.1 - add

>     Bit-precise integer types
>     DW_ATE_signed_bitint    bit-precise signed integer
>     DW_ATE_unsigned_bitint  bit-precise unsigned integer

Add

> 5.1.1.7 Bit-precise integer types
> 
> Bit-precise integer types (`DW_ATE_signed_bitint`,
> `DW_ATE_unsigned_bitint`) are supported in C23 (`_BitInt(N)`
> and `unsigned _BitInt(N)`) and are not discussed further.

Table 7.11 - add

>     DW_ATE_signed_bitint ‡          0x17
>     DW_ATE_unsigned_bitint ‡        0x18

[1]: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3096.pdf

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2023-11-27: Accepted.