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digitalmars.D.ldc - is there a way to do _umul128 on posix ?

reply Newbie2019 <newbie2019 gmail.com> writes:
I need _umul128 to do the fast math,   is there a way to made it 
work for posix ?

On windows I can use _umul128, is there a ASM or work around in 
LDC to do this on posix ?
Sep 09 2019
next sibling parent Newbie2019 <newbie2019 gmail.com> writes:
On Tuesday, 10 September 2019 at 04:13:25 UTC, Newbie2019 wrote:

 I need _umul128 to do the fast math,   is there a way to made 
 it work for posix ?

 On windows I can use _umul128, is there a ASM or work around in 
 LDC to do this on posix ?


I need this to work:  __uint128_t	r = uint64_t * uint64_t;
Sep 09 2019
prev sibling next sibling parent reply a11e99z <black80 bk.ru> writes:
On Tuesday, 10 September 2019 at 04:13:25 UTC, Newbie2019 wrote:

 I need _umul128 to do the fast math,   is there a way to made 
 it work for posix ?

 On windows I can use _umul128, is there a ASM or work around in 
 LDC to do this on posix ?


https://run.dlang.io/is/2xYt5j

struct m128 { ulong lo, hi; }

// REX.W + F7 /4 	MUL r/m64 	(RDX:RAX ← RAX ∗ r/m64).
// 
https://en.wikipedia.org/wiki/X86_calling_conventions#x86-64_calling_conventions
// Windows RCX, RDX, R8, R9. returns RAX only
// Linux RDI, RSI, RDX, RCX, R8, R9. returns RDX:RAX
m128 mul128( ulong a, ulong b ) pure nothrow  nogc  trusted {
     asm pure  nogc nothrow {
	naked;
	mov RAX, RDI;
         mul RSI;
         ret;
     }
}
// probably u can do it inline
Sep 10 2019
parent a11e99z <black80 bk.ru> writes:
On Tuesday, 10 September 2019 at 07:34:49 UTC, a11e99z wrote:

 On Tuesday, 10 September 2019 at 04:13:25 UTC, Newbie2019 wrote:

 I need _umul128 to do the fast math,   is there a way to made 
 it work for posix ?

 On windows I can use _umul128, is there a ASM or work around 
 in LDC to do this on posix ?


 https://run.dlang.io/is/2xYt5j

 struct m128 { ulong lo, hi; }

 // REX.W + F7 /4 	MUL r/m64 	(RDX:RAX ← RAX ∗ r/m64).
 // 
 https://en.wikipedia.org/wiki/X86_calling_conventions#x86-64_calling_conventions
 // Windows RCX, RDX, R8, R9. returns RAX only
 // Linux RDI, RSI, RDX, RCX, R8, R9. returns RDX:RAX
 m128 mul128( ulong a, ulong b ) pure nothrow  nogc  trusted {
     asm pure  nogc nothrow {
 	naked;
 	mov RAX, RDI;
         mul RSI;
         ret;
     }
 }
 // probably u can do it inline


just realized that D uses the registers in the reverse order than 
Linux convention (maybe Windows too).
one more WTF.
Sep 10 2019
prev sibling parent reply Kagamin <spam here.lot> writes:
https://forum.dlang.org/post/nydunscuwdcinamqails forum.dlang.org
Sep 10 2019
parent Newbie2019 <newbie2019 gmail.com> writes:
On Tuesday, 10 September 2019 at 08:50:39 UTC, Kagamin wrote:

 https://forum.dlang.org/post/nydunscuwdcinamqails forum.dlang.org


Thanks, this work great for me.


On Tuesday, 10 September 2019 at 07:34:49 UTC, a11e99z wrote:

 On Tuesday, 10 September 2019 at 04:13:25 UTC, Newbie2019 
 wrote: https://run.dlang.io/is/2xYt5j

 struct m128 { ulong lo, hi; }


Thanks for the tips.
Sep 10 2019