quadrilateralcowboy/idlib/math/Simd_3DNow.cpp
2020-06-12 14:06:25 -07:00

297 lines
10 KiB
C++

/*
===========================================================================
Doom 3 GPL Source Code
Copyright (C) 1999-2011 id Software LLC, a ZeniMax Media company.
This file is part of the Doom 3 GPL Source Code (?Doom 3 Source Code?).
Doom 3 Source Code is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Doom 3 Source Code is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Doom 3 Source Code. If not, see <http://www.gnu.org/licenses/>.
In addition, the Doom 3 Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 Source Code. If not, please request a copy in writing from id Software at the address below.
If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.
===========================================================================
*/
#include "../precompiled.h"
#pragma hdrstop
#include "Simd_Generic.h"
#include "Simd_MMX.h"
#include "Simd_3DNow.h"
//===============================================================
//
// 3DNow! implementation of idSIMDProcessor
//
//===============================================================
#ifdef _WIN32
/*
============
idSIMD_3DNow::GetName
============
*/
const char * idSIMD_3DNow::GetName( void ) const {
return "MMX & 3DNow!";
}
// Very optimized memcpy() routine for all AMD Athlon and Duron family.
// This code uses any of FOUR different basic copy methods, depending
// on the transfer size.
// NOTE: Since this code uses MOVNTQ (also known as "Non-Temporal MOV" or
// "Streaming Store"), and also uses the software prefetchnta instructions,
// be sure you're running on Athlon/Duron or other recent CPU before calling!
#define TINY_BLOCK_COPY 64 // upper limit for movsd type copy
// The smallest copy uses the X86 "movsd" instruction, in an optimized
// form which is an "unrolled loop".
#define IN_CACHE_COPY 64 * 1024 // upper limit for movq/movq copy w/SW prefetch
// Next is a copy that uses the MMX registers to copy 8 bytes at a time,
// also using the "unrolled loop" optimization. This code uses
// the software prefetch instruction to get the data into the cache.
#define UNCACHED_COPY 197 * 1024 // upper limit for movq/movntq w/SW prefetch
// For larger blocks, which will spill beyond the cache, it's faster to
// use the Streaming Store instruction MOVNTQ. This write instruction
// bypasses the cache and writes straight to main memory. This code also
// uses the software prefetch instruction to pre-read the data.
// USE 64 * 1024 FOR THIS VALUE IF YOU'RE ALWAYS FILLING A "CLEAN CACHE"
#define BLOCK_PREFETCH_COPY infinity // no limit for movq/movntq w/block prefetch
#define CACHEBLOCK 80h // number of 64-byte blocks (cache lines) for block prefetch
// For the largest size blocks, a special technique called Block Prefetch
// can be used to accelerate the read operations. Block Prefetch reads
// one address per cache line, for a series of cache lines, in a short loop.
// This is faster than using software prefetch. The technique is great for
// getting maximum read bandwidth, especially in DDR memory systems.
/*
================
idSIMD_3DNow::Memcpy
optimized memory copy routine that handles all alignment cases and block sizes efficiently
================
*/
void VPCALL idSIMD_3DNow::Memcpy( void *dest, const void *src, const int n ) {
__asm {
mov ecx, [n] // number of bytes to copy
mov edi, [dest] // destination
mov esi, [src] // source
mov ebx, ecx // keep a copy of count
cld
cmp ecx, TINY_BLOCK_COPY
jb $memcpy_ic_3 // tiny? skip mmx copy
cmp ecx, 32*1024 // don't align between 32k-64k because
jbe $memcpy_do_align // it appears to be slower
cmp ecx, 64*1024
jbe $memcpy_align_done
$memcpy_do_align:
mov ecx, 8 // a trick that's faster than rep movsb...
sub ecx, edi // align destination to qword
and ecx, 111b // get the low bits
sub ebx, ecx // update copy count
neg ecx // set up to jump into the array
add ecx, offset $memcpy_align_done
jmp ecx // jump to array of movsb's
align 4
movsb
movsb
movsb
movsb
movsb
movsb
movsb
movsb
$memcpy_align_done: // destination is dword aligned
mov ecx, ebx // number of bytes left to copy
shr ecx, 6 // get 64-byte block count
jz $memcpy_ic_2 // finish the last few bytes
cmp ecx, IN_CACHE_COPY/64 // too big 4 cache? use uncached copy
jae $memcpy_uc_test
// This is small block copy that uses the MMX registers to copy 8 bytes
// at a time. It uses the "unrolled loop" optimization, and also uses
// the software prefetch instruction to get the data into the cache.
align 16
$memcpy_ic_1: // 64-byte block copies, in-cache copy
prefetchnta [esi + (200*64/34+192)] // start reading ahead
movq mm0, [esi+0] // read 64 bits
movq mm1, [esi+8]
movq [edi+0], mm0 // write 64 bits
movq [edi+8], mm1 // note: the normal movq writes the
movq mm2, [esi+16] // data to cache; a cache line will be
movq mm3, [esi+24] // allocated as needed, to store the data
movq [edi+16], mm2
movq [edi+24], mm3
movq mm0, [esi+32]
movq mm1, [esi+40]
movq [edi+32], mm0
movq [edi+40], mm1
movq mm2, [esi+48]
movq mm3, [esi+56]
movq [edi+48], mm2
movq [edi+56], mm3
add esi, 64 // update source pointer
add edi, 64 // update destination pointer
dec ecx // count down
jnz $memcpy_ic_1 // last 64-byte block?
$memcpy_ic_2:
mov ecx, ebx // has valid low 6 bits of the byte count
$memcpy_ic_3:
shr ecx, 2 // dword count
and ecx, 1111b // only look at the "remainder" bits
neg ecx // set up to jump into the array
add ecx, offset $memcpy_last_few
jmp ecx // jump to array of movsd's
$memcpy_uc_test:
cmp ecx, UNCACHED_COPY/64 // big enough? use block prefetch copy
jae $memcpy_bp_1
$memcpy_64_test:
or ecx, ecx // tail end of block prefetch will jump here
jz $memcpy_ic_2 // no more 64-byte blocks left
// For larger blocks, which will spill beyond the cache, it's faster to
// use the Streaming Store instruction MOVNTQ. This write instruction
// bypasses the cache and writes straight to main memory. This code also
// uses the software prefetch instruction to pre-read the data.
align 16
$memcpy_uc_1: // 64-byte blocks, uncached copy
prefetchnta [esi + (200*64/34+192)] // start reading ahead
movq mm0,[esi+0] // read 64 bits
add edi,64 // update destination pointer
movq mm1,[esi+8]
add esi,64 // update source pointer
movq mm2,[esi-48]
movntq [edi-64], mm0 // write 64 bits, bypassing the cache
movq mm0,[esi-40] // note: movntq also prevents the CPU
movntq [edi-56], mm1 // from READING the destination address
movq mm1,[esi-32] // into the cache, only to be over-written
movntq [edi-48], mm2 // so that also helps performance
movq mm2,[esi-24]
movntq [edi-40], mm0
movq mm0,[esi-16]
movntq [edi-32], mm1
movq mm1,[esi-8]
movntq [edi-24], mm2
movntq [edi-16], mm0
dec ecx
movntq [edi-8], mm1
jnz $memcpy_uc_1 // last 64-byte block?
jmp $memcpy_ic_2 // almost done
// For the largest size blocks, a special technique called Block Prefetch
// can be used to accelerate the read operations. Block Prefetch reads
// one address per cache line, for a series of cache lines, in a short loop.
// This is faster than using software prefetch, in this case.
// The technique is great for getting maximum read bandwidth,
// especially in DDR memory systems.
$memcpy_bp_1: // large blocks, block prefetch copy
cmp ecx, CACHEBLOCK // big enough to run another prefetch loop?
jl $memcpy_64_test // no, back to regular uncached copy
mov eax, CACHEBLOCK / 2 // block prefetch loop, unrolled 2X
add esi, CACHEBLOCK * 64 // move to the top of the block
align 16
$memcpy_bp_2:
mov edx, [esi-64] // grab one address per cache line
mov edx, [esi-128] // grab one address per cache line
sub esi, 128 // go reverse order
dec eax // count down the cache lines
jnz $memcpy_bp_2 // keep grabbing more lines into cache
mov eax, CACHEBLOCK // now that it's in cache, do the copy
align 16
$memcpy_bp_3:
movq mm0, [esi ] // read 64 bits
movq mm1, [esi+ 8]
movq mm2, [esi+16]
movq mm3, [esi+24]
movq mm4, [esi+32]
movq mm5, [esi+40]
movq mm6, [esi+48]
movq mm7, [esi+56]
add esi, 64 // update source pointer
movntq [edi ], mm0 // write 64 bits, bypassing cache
movntq [edi+ 8], mm1 // note: movntq also prevents the CPU
movntq [edi+16], mm2 // from READING the destination address
movntq [edi+24], mm3 // into the cache, only to be over-written,
movntq [edi+32], mm4 // so that also helps performance
movntq [edi+40], mm5
movntq [edi+48], mm6
movntq [edi+56], mm7
add edi, 64 // update dest pointer
dec eax // count down
jnz $memcpy_bp_3 // keep copying
sub ecx, CACHEBLOCK // update the 64-byte block count
jmp $memcpy_bp_1 // keep processing chunks
// The smallest copy uses the X86 "movsd" instruction, in an optimized
// form which is an "unrolled loop". Then it handles the last few bytes.
align 4
movsd
movsd // perform last 1-15 dword copies
movsd
movsd
movsd
movsd
movsd
movsd
movsd
movsd // perform last 1-7 dword copies
movsd
movsd
movsd
movsd
movsd
movsd
$memcpy_last_few: // dword aligned from before movsd's
mov ecx, ebx // has valid low 2 bits of the byte count
and ecx, 11b // the last few cows must come home
jz $memcpy_final // no more, let's leave
rep movsb // the last 1, 2, or 3 bytes
$memcpy_final:
emms // clean up the MMX state
sfence // flush the write buffer
mov eax, [dest] // ret value = destination pointer
}
}
#endif /* _WIN32 */