mirrors/dmd
1
0
Fork 0
mirror of https://github.com/dlang/dmd.git synced 2025-04-26 13:10:12 +03:00
Code Issues Projects Releases Packages Wiki Activity Actions 5

[druntime] core.int128: Optimize new udivmod overload via inline asm on x86_64

Browse source
This commit is contained in:
Martin Kinkelin 2025-03-24 01:22:58 +01:00 • committed by Nicholas Wilson
parent 3a661c1f8c
commit 6b7bbdd330
1 changed files with 39 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

40
druntime/src/core/int128.d
View file

@ -562,6 +562,12 @@ Cent udivmod(Cent c1, Cent c2, out Cent modulus)
return quotient;
}
version (X86_64)
{
version (GNU) version = GNU_OR_LDC_X86_64;
version (LDC) version = GNU_OR_LDC_X86_64;
}
/****************************
* Unsigned divide 128-bit c1 / 64-bit c2. The result must fit in 64 bits.
* The remainder after division is stored to modulus.
@ -577,6 +583,39 @@ U udivmod(Cent c1, U c2, out U modulus)
{
import core.bitop;
if (!__ctfe)
{
version (GNU_OR_LDC_X86_64)
{
U ret = void;
asm pure @trusted nothrow @nogc
{
"divq %4"
: "=a"(ret), "=d"(modulus)
: "a"(c1.lo), "d"(c1.hi), "r"(c2)
: "cc";
}
return ret;
}
else version (D_InlineAsm_X86_64)
{
const lo = c1.lo;
const hi = c1.hi;
U mod = void;
U ret = void;
asm pure @trusted nothrow @nogc
{
mov RAX, lo;
mov RDX, hi;
div c2;
mov mod, RDX; // DMD bug: cannot use modulus directly
mov ret, RAX;
}
modulus = mod;
return ret;
}
}
// We work in base 2^^32
enum base = 1UL << 32;
enum divmask = (1UL << (Ubits / 2)) - 1;
@ -918,7 +957,6 @@ unittest
assert(udiv(C10,C2) == C5);
assert(udivmod(C10,C2, modulus) == C5); assert(modulus == C0);
assert(udivmod(C10,C3, modulus) == C3); assert(modulus == C1);
assert(udivmod(C10,C0, modulus) == Cm1); assert(modulus == C0);
assert(udivmod(C2,C90_30, modulus) == C0); assert(modulus == C2);
assert(udiv(mul(C90_30, C2), C2) == C90_30);
assert(udiv(mul(C90_30, C2), C90_30) == C2);