[Bug inline-asm/37621] Missing documentation for x86 inline assembler modifiers

[Bug inline-asm/37621] Missing documentation for x86 inline assembler modifiers

[gerald at pfeifer dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=37621

Gerald Pfeifer <gerald at pfeifer dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |gerald at pfeifer dot com
         Resolution|---                         |FIXED

--- Comment #4 from Gerald Pfeifer <gerald at pfeifer dot com> ---
I checked, and
https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#i386Operandmodifiers
now covers this as part of the general documentation so I am closing this
report as fixed.

Please advise if I missed anything.

[Bug inline-asm/37621] Missing documentation for x86 inline assembler modifiers

[n dot pipenbrinck at cubic dot org]

------- Comment #3 from n dot pipenbrinck at cubic dot org  2008-09-24 22:41 -------
ROL/ROR on the native integer size is not supported via intrinsics, but the
compiler will fold two shifts into a rotate.

If I want to manipulate only the lower 16 bit of an 32 bit integer (e.g. issue
a rolw) assembly is the only way it's currently possible.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37621

[Bug inline-asm/37621] Missing documentation for x86 inline assembler modifiers

[dlenski at gmail dot com]

------- Comment #2 from dlenski at gmail dot com  2008-09-24 17:43 -------
Hi Andrew,
It seems to me that these modifiers are quite necessary for flexible x86
assembly.  What is the point of the "q" and "Q" constraints if there's no way
to specifically refer to the 16-bit or 8-bit components of the selected
register?

And are you sure there built-in functions to invoke the rol/ror/xhcg
instructions?  I don't see any in the 4.3 docs.

Dan


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37621

[Bug inline-asm/37621] Missing documentation for x86 inline assembler modifiers

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2008-09-24 00:35 -------
IIRC these are not documented because they can and will change at any time and
don't always produce correct code.

Also you can use most of the builtin functions to get the same as the
inline-asm ...


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37621