Is this an appropriate place to ask about CIL?

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Jon Shemitz - 04 Oct 2003 04:42 GMT

Partition III, section 1.1.2 says "A CLI Boolean type occupies one
byte in memory. A bit pattern of all zeroes denotes a value of false.
A bit pattern with any one or more bits set (analogous to a non-zero
integer) denotes a value of true."

Where does CIL actually use this datatype? The Cxx instructions put an
int32 on the stack; the brtrue and brfalse instructions take 32-bit
values, not a 1-byte boolean.

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Ori Gershony [MSFT] - 06 Oct 2003 23:27 GMT

The evaluation stack uses the natural word size of the machine, but the
types themselves can have a different in-memory representations, and as a
result will get expanded when they will be loaded into the evaluation stack
(via ldloc, ldfld, etc.). In the case of the Boolean type, this can save
you 3 bytes on 32bit machines (assuming you have other small types to pack
the structure with).

-- Ori.

--------------------

>Message-ID: <3F7E41BC.6F333EC5@midnightbeach.com>
>Date: Fri, 03 Oct 2003 20:42:52 -0700
[quoted text clipped - 22 lines]
>int32 on the stack; the brtrue and brfalse instructions take 32-bit
>values, not a 1-byte boolean.

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Jon Shemitz - 07 Oct 2003 05:04 GMT

> The evaluation stack uses the natural word size of the machine, but the
> types themselves can have a different in-memory representations, and as a
> result will get expanded when they will be loaded into the evaluation stack
> (via ldloc, ldfld, etc.). In the case of the Boolean type, this can save
> you 3 bytes on 32bit machines (assuming you have other small types to pack
> the structure with).

Thx. I'd already found that C# could ld a bool and brtrue or brfalse
it, and seen a line or two in the docs that sort of allude to this -
this is a deeper explanation than I've seen.

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Is this an appropriate place to ask about CIL?

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