Add support for VECTORCALL calling convention

[john-terraspace]

Available from VS2013 onwards, supports passing of XMMWORD, YMMWORD, ZMMWORD types through registers like fastcall.

[habran]

supports passing of XMMWORD, YMMWORD, ZMMWORD types through registers like fastcall

please explain

On Mon, Feb 8, 2016 at 8:28 PM, John Hankinson notifications@github.com wrote:

Available from VS2013 onwards, supports passing of XMMWORD, YMMWORD, ZMMWORD types through registers like fastcall

— Reply to this email directly or view it on GitHub https://github.com/Terraspace/HJWasm/issues/27.

[john-terraspace]

Since VS2013 they’ve extended the normal WIN64 fastcall convention to allow vectors (any simd register to be passed in registers)..

https://blogs.msdn.microsoft.com/vcblog/2013/07/11/introducing-vector-calling-convention/

It’s been around for a while.

I’ve not checked exactly what jwasm or hjwasm would do in these cases but I believe we stick to the old fastcall standard..

So if you had:

myProc PROC FRAME arg1:XMMWORD, arg2:XMMWORD …

arg1 and arg2 would be passed by reference… IE:

invoke myProc, myVector, myVector

000000013FBD82B9 48 8D 0D AB 49 DE 00 lea rcx,[myVector (01409BCC6Bh)]

000000013FBD82C0 48 8D 15 A4 49 DE 00 lea rdx,[myVector (01409BCC6Bh)]

000000013FBD82C7 E8 1E FF FF FF call TestProc (013FBD81EAh)

Further more the vectorcall calling convention would allow you to also use registers like you do with fastcall

So..

Invoke myProc xmm0, myVector

In both cases then you should get something like:

movaps xmm0,xmm0

movaps xmm1,myVector

when generating the invoke.

The only thing I’m not sure about is how I would use my SIMD struct types with this, because by default XMMWORD etc don’t produce very good debugging info..

Ie:

If you debug and check out an xmmword type you get:

• myVector 0x00000001409bcc6b {0, 0, 0, 0, 0, 0, 0, 0} unsigned __int64[8]

Which is complete rubbish.. it should be 4 floats or 4 integers.. because of that I normally use :

; A proper type definition for an XMMWORD and YMMWORD that allows debugger to see sub-elements/types.

__mm128i struct

            i0 DWORD ?

            i1 DWORD ?

            i2 DWORD ?

            i3 DWORD ?        

__mm128i ends

_mm128i typedef __mm128i

__mm128f struct

            f0 real4 ?

            f1 real4 ?

            f2 real4 ?

            f3 real4 ?

__mm128f ends

_mm128f typedef __mm128f

_mm128 union

            i32 _mm128i <>

            f32 _mm128f <> 

_mm128 ends

From: habran [mailto:notifications@github.com] Sent: 08 February 2016 10:18 AM To: Terraspace/HJWasm HJWasm@noreply.github.com Cc: John Hankinson john@terraspace.co.uk Subject: Re: [HJWasm] Add support for VECTORCALL calling convention (#27)

supports passing of XMMWORD, YMMWORD, ZMMWORD types through registers like fastcall

please explain

On Mon, Feb 8, 2016 at 8:28 PM, John Hankinson notifications@github.com wrote:

Available from VS2013 onwards, supports passing of XMMWORD, YMMWORD, ZMMWORD types through registers like fastcall

— Reply to this email directly or view it on GitHub https://github.com/Terraspace/HJWasm/issues/27.

— Reply to this email directly or view it on GitHub https://github.com/Terraspace/HJWasm/issues/27#issuecomment-181292501 .

[john-terraspace]

Done in 2.15