Navigation Menu

Skip to content

Instantly share code, notes, and snippets.

@dougallj

dougallj/crc32_12.cpp Secret

Created May 22, 2022 14:21
Show Gist options
  • Star 13 You must be signed in to star a gist
  • Fork 2 You must be signed in to fork a gist
  • Save dougallj/a15a0feac92e2126932b0fbe1de7863d to your computer and use it in GitHub Desktop.
Save dougallj/a15a0feac92e2126932b0fbe1de7863d to your computer and use it in GitHub Desktop.
Download ZIP
12-wide CRC32
Raw
crc32_12.cpp
#include <arm_neon.h>
#include <stdint.h>
#include <stdlib.h>
// WARNING: DO NOT USE - demo of performance only. This has not been properly
// tested/checked, and does not handle unaligned sizes/pointers correctly.
//
// Codegen is very fragile - should be rewritten in assembly.
static uint8x16_t reduce(uint8x16_t a, uint8x16_t b, poly64x2_t k) {
uint8x16_t c =
vreinterpretq_u8_p128(vmull_p64(vreinterpretq_p64_u8(a)[0], k[0]));
uint8x16_t d =
vreinterpretq_u8_p128(vmull_high_p64(vreinterpretq_p64_u8(a), k));
return veorq_u8(veorq_u8(b, c), d);
}
poly64x2_t k1k2 = {0x1821d8bc0, 0x12e958ac4};
poly64x2_t k3k4 = {0x1751997d0, 0x0ccaa009e};
uint32_t my_crc_arm64(uint32_t crc, uint8_t *p, size_t size) {
uint64_t k1 = 0x1821d8bc0;
uint64_t k2 = 0x12e958ac4;
uint64_t k3 = 0x1751997d0;
uint64_t k4 = 0xccaa009e;
uint64_t k5 = 0x163cd6124;
uint64_t k6 = 0x1db710640;
// Step 1: fold by 4 loop
uint8x16_t val0 = vld1q_u8(p);
p += 0x10;
size -= 0x10;
uint8x16_t val1 = vld1q_u8(p);
p += 0x10;
size -= 0x10;
uint8x16_t val2 = vld1q_u8(p);
p += 0x10;
size -= 0x10;
uint8x16_t val3 = vld1q_u8(p);
p += 0x10;
size -= 0x10;
uint8x16_t val4 = vld1q_u8(p);
p += 0x10;
size -= 0x10;
uint8x16_t val5 = vld1q_u8(p);
p += 0x10;
size -= 0x10;
uint8x16_t val6 = vld1q_u8(p);
p += 0x10;
size -= 0x10;
uint8x16_t val7 = vld1q_u8(p);
p += 0x10;
size -= 0x10;
uint8x16_t val8 = vld1q_u8(p);
p += 0x10;
size -= 0x10;
uint8x16_t val9 = vld1q_u8(p);
p += 0x10;
size -= 0x10;
uint8x16_t val10 = vld1q_u8(p);
p += 0x10;
size -= 0x10;
uint8x16_t val11 = vld1q_u8(p);
p += 0x10;
size -= 0x10;
// fold in our initial value, part of the incremental crc checksum
uint32x4_t init = {~crc, 0, 0, 0};
val0 = veorq_u8(val0, init);
// poly64x2_t k1k2 = { k1, k2 };
// char *end = p + (size / (16*12) * (16*12))
while (size > 16 * 12) {
val0 = reduce(val0, vld1q_u8(p), k1k2);
p += 0x10;
size -= 0x10;
val1 = reduce(val1, vld1q_u8(p), k1k2);
p += 0x10;
size -= 0x10;
val2 = reduce(val2, vld1q_u8(p), k1k2);
p += 0x10;
size -= 0x10;
val3 = reduce(val3, vld1q_u8(p), k1k2);
p += 0x10;
size -= 0x10;
val4 = reduce(val4, vld1q_u8(p), k1k2);
p += 0x10;
size -= 0x10;
val5 = reduce(val5, vld1q_u8(p), k1k2);
p += 0x10;
size -= 0x10;
val6 = reduce(val6, vld1q_u8(p), k1k2);
p += 0x10;
size -= 0x10;
val7 = reduce(val7, vld1q_u8(p), k1k2);
p += 0x10;
size -= 0x10;
val8 = reduce(val8, vld1q_u8(p), k1k2);
p += 0x10;
size -= 0x10;
val9 = reduce(val9, vld1q_u8(p), k1k2);
p += 0x10;
size -= 0x10;
val10 = reduce(val10, vld1q_u8(p), k1k2);
p += 0x10;
size -= 0x10;
val11 = reduce(val11, vld1q_u8(p), k1k2);
p += 0x10;
size -= 0x10;
}
uint8x16_t x = val0;
x = reduce(x, val1, k3k4);
x = reduce(x, val2, k3k4);
x = reduce(x, val3, k3k4);
x = reduce(x, val4, k3k4);
x = reduce(x, val5, k3k4);
x = reduce(x, val6, k3k4);
x = reduce(x, val7, k3k4);
x = reduce(x, val8, k3k4);
x = reduce(x, val9, k3k4);
x = reduce(x, val10, k3k4);
x = reduce(x, val11, k3k4);
while (size >= 16) {
x = reduce(x, vld1q_u8(p), k3k4);
p += 0x10;
size -= 0x10;
}
poly64x2_t k4k5 = {0xccaa009e, 0x163cd6124};
poly64x2_t final = {0x1F7011641, 0x1DB710641};
uint32x4_t b =
vreinterpretq_u8_p128(vmull_p64(vreinterpretq_p64_u8(x)[0], k4k5[0]));
uint64x2_t c = {vreinterpretq_p64_u8(x)[1], 0};
uint32x4_t a = veorq_u8(c, b);
uint32x4_t d = {0, 0, 0, 0};
d[2] = a[0];
a[0] = a[1];
a[1] = a[2];
b = a;
a = vreinterpretq_u8_p128(vmull_high_p64(vreinterpretq_p64_u8(d), k4k5));
a = veorq_u8(a, b);
d[0] = a[0];
b = vreinterpretq_u8_p128(vmull_p64(vreinterpretq_p64_u8(d)[0], final[0]));
d[2] = b[0];
b = a;
a = vreinterpretq_u8_p128(vmull_high_p64(vreinterpretq_p64_u8(d), final));
a = veorq_u8(a, b);
return ~a[1];
}
Raw
main.cpp
// clang++ -std=c++17 -O3 main.cpp crc32_12.cpp && ./a.out
// WARNING: DO NOT USE - demo of performance only. This has not been properly
// tested/checked, and does not handle unaligned sizes/pointers correctly.
#include <arm_neon.h>
#include <assert.h>
#include <chrono>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
uint64_t nano() {
return std::chrono::duration_cast<::std::chrono::nanoseconds>(
std::chrono::steady_clock::now().time_since_epoch())
.count();
}
// from https://github.com/richgel999/fpng
// Precomputed 4KB of CRC-32 tables
static const uint32_t g_crc32_4[4][256] = {
{
00, 016701630226, 035603460454, 023102250672, 0733342031,
016032572217, 035130722465, 023631112643, 01666704062, 017167134244,
034065364436, 022764554610, 01155446053, 017654276275, 034756026407,
022057616621, 03555610144, 015254020362, 036356270510, 020457440736,
03266552175, 015567362353, 036465132521, 020364702707, 02333114126,
014432724300, 037530574572, 021231344754, 02400256117, 014301466331,
037203636543, 021502006765, 07333420310, 011432210136, 032530040744,
024231670562, 07400762321, 011301152107, 032203302775, 024502532553,
06555324372, 010254514154, 033356744726, 025457174500, 06266066343,
010567656165, 033465406717, 025364236531, 04666230254, 012167400072,
031065650600, 027764060426, 04155172265, 012654742043, 031756512631,
027057322417, 05000534236, 013701304010, 030603154662, 026102764444,
05733676207, 013032046021, 030130216653, 026631426475, 016667040620,
0166670406, 023064420274, 035765210052, 016154302611, 0655532437,
023757762245, 035056152063, 017001744642, 01700174464, 022602324216,
034103514030, 017732406673, 01033236455, 022131066227, 034630656001,
015332650764, 03433060542, 020531230330, 036230400116, 015401512755,
03300322573, 020202172301, 036503742127, 014554154706, 02255764520,
021357534352, 037456304174, 014267216737, 02566426511, 021464676363,
037365046145, 011554460530, 07255250716, 024357000164, 032456630342,
011267722501, 07566112727, 024464342155, 032365572373, 010332364552,
06433554774, 025531704106, 033230134320, 010401026563, 06300616745,
025202446137, 033503276311, 012001270474, 04700440652, 027602610020,
031103020206, 012732132445, 04033702663, 027131552011, 031630362237,
013667574416, 05166344630, 026064114042, 030765724264, 013154636427,
05655006601, 026757256073, 030056466255, 035556101440, 023257731666,
0355561014, 016454351232, 035265243471, 023564473657, 0466623025,
016367013203, 034330605422, 022431035604, 01533265076, 017232455250,
034403547413, 022302377635, 01200127047, 017501717261, 036003711504,
020702121722, 03600371150, 015101541376, 036730453535, 020031263713,
03133033161, 015632603347, 037665015566, 021164625740, 02066475132,
014767245314, 037156357557, 021657567771, 02755737103, 014054107325,
032665521750, 024164311576, 07066141304, 011767771122, 032156663761,
024657053547, 07755203335, 011054433113, 033003225732, 025702415514,
06600645366, 010101075140, 033730167703, 025031757525, 06133507357,
010632337171, 031330331614, 027431501432, 04533751240, 012232161066,
031403073625, 027302643403, 04200413271, 012501223057, 030556435676,
026257205450, 05355055222, 013454665004, 030265777647, 026564147461,
05466317213, 013367527035, 023331141260, 035430771046, 016532521634,
0233311412, 023402203251, 035303433077, 016201663605, 0500053423,
022557645202, 034256075024, 017354225656, 01455415470, 022264507233,
034565337015, 017467167667, 01366757441, 020664751324, 036165161102,
015067331770, 03766501556, 020157413315, 036656223133, 015754073741,
03055643567, 021002055346, 037703665160, 014601435712, 02100205534,
021731317377, 037030527151, 014132777723, 02633147505, 024002561170,
032703351356, 011601101524, 07100731702, 024731623141, 032030013367,
011132243515, 07633473733, 025664265112, 033165455334, 010067605546,
06766035760, 025157127123, 033656717305, 010754547577, 06055377751,
027557371034, 031256541212, 012354711460, 04455121646, 027264033005,
031565603223, 012467453451, 04366263677, 026331475056, 030430245270,
013532015402, 05233625624, 026402737067, 030303107241, 013201357433,
05500567615,
},
{
00, 03106630501, 06215461202, 05313251703, 014433142404,
017535772105, 012626523606, 011720313307, 031066305010, 032160535511,
037273764212, 034375154713, 025455247414, 026553477115, 023640626616,
020746016317, 011260411121, 012366221420, 017075070323, 014173640622,
05653553525, 06755363024, 03446132727, 0540702226, 020206714131,
023300124430, 026013375333, 025115545632, 034635656535, 037733066034,
032420237737, 031526407236, 022541022242, 021447612743, 024754443040,
027652273541, 036172160646, 035074750347, 030367501444, 033261331145,
013527327252, 010421517753, 015732746050, 016634176551, 07114265656,
04012455357, 01301604454, 02207034155, 033721433363, 030627203662,
035534052161, 036432662460, 027312571767, 024214341266, 021107110565,
022001720064, 02747736373, 01641106672, 04552357171, 07454567470,
016374674777, 015272044276, 010161215575, 013067425074, 036036247405,
035130477104, 030223626607, 033325016306, 022405305001, 021503535500,
024610764203, 027716154702, 07050142415, 04156772114, 01245523617,
02343313316, 013463000011, 010565630510, 015676461213, 016770251712,
027256656524, 024350066025, 021043237726, 022145407227, 033665714120,
030763124421, 035470375322, 036576545623, 016230553534, 015336363035,
010025132736, 013123702237, 02603411130, 01705221431, 04416070332,
07510640633, 014577265647, 017471455346, 012762604445, 011664034144,
0144327243, 03042517742, 06351746041, 05257176540, 025511160657,
026417750356, 023704501455, 020602331154, 031122022253, 032024612752,
037337443051, 034231273550, 05717674766, 06611044267, 03502215564,
0404425065, 011324736362, 012222106663, 017131357160, 014037567461,
034771571776, 037677341277, 032564110574, 031462720075, 020342433372,
023244203673, 026157052170, 025051662471, 07340714113, 04246124412,
01155375311, 02053545610, 013773656517, 010675066016, 015566237715,
016460407214, 036326411103, 035220221402, 030133070301, 033035640600,
022715553507, 021613363006, 024500132705, 027406702204, 016120305032,
015026535533, 010335764230, 013233154731, 02513247436, 01415477137,
04706626634, 07600016335, 027146000022, 024040630523, 021353461220,
022255251721, 033575142426, 030473772127, 035760523624, 036666313325,
025601736351, 026707106650, 023414357153, 020512567452, 031232674755,
032334044254, 037027215557, 034121425056, 014667433341, 017761203640,
012472052143, 011574662442, 0254571745, 03352341244, 06041110547,
05147720046, 034461327270, 037567517771, 032674746072, 031772176573,
020052265674, 023154455375, 026247604476, 025341034177, 05407022260,
06501612761, 03612443062, 0714273563, 011034160664, 012132750365,
017221501466, 014327331167, 031376553516, 032270363017, 037163132714,
034065702215, 025745411112, 026643221413, 023550070310, 020456640611,
0310656506, 03216066007, 06105237704, 05003407205, 014723714102,
017625124403, 012536375300, 011430545601, 020116142437, 023010772136,
026303523635, 025205313334, 034525000033, 037423630532, 032730461231,
031636251730, 011170247427, 012076477126, 017365626625, 014263016324,
05543305023, 06445535522, 03756764221, 0650154720, 013637571754,
010731341255, 015422110556, 016524720057, 07204433350, 04302203651,
01011052152, 02117662453, 022651674744, 021757044245, 024444215546,
027542425047, 036262736340, 035364106641, 030077357142, 033171567443,
02457160675, 01551750374, 04642501477, 07744331176, 016064022271,
015162612770, 010271443073, 013377273572, 033431265665, 030537455364,
035624604467, 036722034166, 027002327261, 024104517760, 021217746063,
022311176562,
},
{
00, 0160465067, 0341152156, 0221537131, 0702324334,
0662741353, 0443276262, 0523613205, 01604650670, 01764235617,
01545702726, 01425367741, 01106574544, 01066111523, 01247426412,
01327043475, 03411521560, 03571144507, 03750473436, 03630016451,
03313605654, 03273260633, 03052757702, 03132332765, 02215371310,
02375714377, 02154223246, 02034646221, 02517055024, 02477430043,
02656107172, 02736562115, 07023243340, 07143626327, 07362311216,
07202774271, 07721167074, 07641502013, 07460035122, 07500450145,
06627413530, 06747076557, 06566541466, 06406124401, 06125737604,
06045352663, 06264665752, 06304200735, 04432762620, 04552307647,
04773630776, 04613255711, 04330446514, 04250023573, 04071514442,
04111171425, 05236132050, 05356557037, 05177060106, 05017405161,
05534216364, 05454673303, 05675344232, 05715721255, 016046506700,
016126163767, 016307454656, 016267031631, 016744622434, 016624247453,
016405770562, 016565315505, 017642356170, 017722733117, 017503204026,
017463661041, 017140072244, 017020417223, 017201120312, 017361545375,
015457027260, 015537442207, 015716175336, 015676510351, 015355303154,
015235766133, 015014251002, 015174634065, 014253677410, 014333212477,
014112725546, 014072340521, 014551553724, 014431136743, 014610401672,
014770064615, 011065745440, 011105320427, 011324617516, 011244272571,
011767461774, 011607004713, 011426533622, 011546156645, 010661115230,
010701570257, 010520047366, 010440422301, 010163231104, 010003654163,
010222363052, 010342706035, 012474264120, 012514601147, 012735336076,
012655753011, 012376140214, 012216525273, 012037012342, 012157477325,
013270434750, 013310051737, 013131566606, 013051103661, 013572710464,
013412375403, 013633642532, 013753227555, 034115215600, 034075670667,
034254347756, 034334722731, 034617131534, 034777554553, 034556063462,
034436406405, 035711445070, 035671020017, 035450517126, 035530172141,
035013761344, 035173304323, 035352633212, 035232256275, 037504734360,
037464351307, 037645666236, 037725203251, 037206410054, 037366075033,
037147542102, 037027127165, 036300164510, 036260501577, 036041036446,
036121453421, 036402240624, 036562625643, 036743312772, 036623777715,
033136056540, 033056433527, 033277104416, 033317561471, 033634372674,
033754717613, 033575220722, 033415645745, 032732606330, 032652263357,
032473754266, 032513331201, 032030522004, 032150147063, 032371470152,
032211015135, 030527577020, 030447112047, 030666425176, 030706040111,
030225653314, 030345236373, 030164701242, 030004364225, 031323327650,
031243742637, 031062275706, 031102610761, 031421003564, 031541466503,
031760151432, 031600534455, 022153713100, 022033376167, 022212641056,
022372224031, 022651437234, 022731052253, 022510565362, 022470100305,
023757143770, 023637526717, 023416011626, 023576474641, 023055267444,
023135602423, 023314335512, 023274750575, 021542232460, 021422657407,
021603360536, 021763705551, 021240116754, 021320573733, 021101044602,
021061421665, 020346462210, 020226007277, 020007530346, 020167155321,
020444746124, 020524323143, 020705614072, 020665271015, 025170550240,
025010135227, 025231402316, 025351067371, 025672674174, 025712211113,
025533726022, 025453343045, 024774300430, 024614765457, 024435252566,
024555637501, 024076024704, 024116441763, 024337176652, 024257513635,
026561071720, 026401414747, 026620123676, 026740546611, 026263355414,
026303730473, 026122207542, 026042662525, 027365621150, 027205244137,
027024773006, 027144316061, 027467505264, 027507160203, 027726457332,
027646032355,
},
{
00, 027057063545, 025202344213, 02255327756, 021730513527,
06767570062, 04532657734, 023565634271, 030555024357, 017502047612,
015757360144, 032700303401, 011265537670, 036232554335, 034067673463,
013030610126, 012006253637, 035051230372, 037204117424, 010253174161,
033736740310, 014761723655, 016534404103, 031563467446, 022553277560,
05504214025, 07751133773, 020706150236, 03263764047, 024234707502,
026061420254, 01036443711, 024014527476, 03043544133, 01216663665,
026241600320, 05724034151, 022773057414, 020526370342, 07571313607,
014541503721, 033516560264, 031743647532, 016714624077, 035271010206,
012226073743, 010073354015, 037024337550, 036012774241, 011045717704,
013210430052, 034247453517, 017722267766, 030775204223, 032520123575,
015577140030, 06547750116, 021510733453, 023745414305, 04712477640,
027277243431, 0220220174, 02075107622, 025022164367, 023305054075,
04352037530, 06107310266, 021150373723, 02435547552, 025462524017,
027637603741, 0660660204, 013650070322, 034607013667, 036452334131,
011405357474, 032160563605, 015137500340, 017362627416, 030335644153,
031303207642, 016354264307, 014101143451, 033156120114, 010433714365,
037464777620, 035631450176, 012666433433, 01656223515, 026601240050,
024454167706, 03403104243, 020166730032, 07131753577, 05364474221,
022333417764, 07311573403, 020346510146, 022113637610, 05144654355,
026421060124, 01476003461, 03623324337, 024674347672, 037644557754,
010613534211, 012446613547, 035411670002, 016174044273, 031123027736,
033376300060, 014321363525, 015317720234, 032340743771, 030115464027,
017142407562, 034427233713, 013470250256, 011625177500, 036672114045,
025642704163, 02615767426, 0440440370, 027417423635, 04172217444,
023125274101, 021370153657, 06327130312, 035526333073, 012571350536,
010724077260, 037773014725, 014216620554, 033241643011, 031014564747,
016043507202, 05073317324, 022024374661, 020271053137, 07226030472,
024743604603, 03714667346, 01541540410, 026516523155, 027520160644,
0577103301, 02722224457, 025775247112, 06210473363, 021247410626,
023012737170, 04045754435, 017075144513, 030022127056, 032277200700,
015220263245, 036745457034, 011712434571, 013547713227, 034510770762,
011532614405, 036565677140, 034730550616, 013767533353, 030202307122,
017255364467, 015000043331, 032057020674, 021067630752, 06030653217,
04265574541, 023232517004, 0757323275, 027700340730, 025555067066,
02502004523, 03534447232, 024563424777, 026736703021, 01761760564,
022204154715, 05253137250, 07006210506, 020051273043, 033061463165,
014036400420, 016263727376, 031234744633, 012751170442, 035706113107,
037553234651, 010504257314, 016623367006, 031674304543, 033421023215,
014476040750, 037113674521, 010144617064, 012311530732, 035346553277,
026376343351, 01321320614, 03174007142, 024123064407, 07446650676,
020411633333, 022644514465, 05613577120, 04625134631, 023672157374,
021427270422, 06470213167, 025115427316, 02142444653, 0317763105,
027340700440, 034370110566, 013327173023, 011172254775, 036125237230,
015440403041, 032417460504, 030642747252, 017615724717, 032637640470,
015660623135, 017435504663, 030462567326, 013107353157, 034150330412,
036305017344, 011352074601, 02362664727, 025335607262, 027160520534,
0137543071, 023452377200, 04405314745, 06650033013, 021607050556,
020631413247, 07666470702, 05433757054, 022464734511, 01101100760,
026156163225, 024303244573, 03354227036, 010364437110, 037333454455,
035166773303, 012131710646, 031454124437, 016403147172, 014656260624,
033601203361,
}};
static uint32_t crc32_slice_by_4(const void *pData, size_t data_len,
uint32_t cur_crc32 = 0) {
uint32_t crc = ~cur_crc32;
const uint32_t *pData32 = static_cast<const uint32_t *>(pData);
for (; data_len >= sizeof(uint32_t); ++pData32, data_len -= 4) {
uint32_t v = *pData32 ^ crc;
crc = g_crc32_4[0][v >> 24] ^ g_crc32_4[1][(v >> 16) & 0xFF] ^
g_crc32_4[2][(v >> 8) & 0xFF] ^ g_crc32_4[3][v & 0xFF];
}
for (const uint8_t *pData8 = reinterpret_cast<const uint8_t *>(pData32);
data_len; --data_len)
crc = (crc >> 8) ^ g_crc32_4[0][(crc & 0xFF) ^ *pData8++];
return ~crc;
}
uint32_t my_crc_arm64(uint32_t crc, uint8_t *p, size_t size);
int main() {
size_t data_size = 2 * 1024 * 1024;
uint8_t *data = (uint8_t *)malloc(data_size);
for (size_t i = 0; i < data_size; i++)
data[i] = rand();
uint32_t expected = 0;
expected = crc32_slice_by_4(data, data_size, 0);
printf("expected: %x\n", expected);
uint32_t result = my_crc_arm64(0, data, data_size);
printf("result: %x\n", result);
assert(result == expected);
for (int i = 0; i < 10; i++) {
uint64_t start = nano();
int n = 3000;
for (int j = 0; j < n; j++)
result = my_crc_arm64(0, data, data_size);
uint64_t end = nano();
printf("%lfgb/s\n", (data_size / ((double)(end - start) / n / 1000000000.0)) / 1000000000.0);
}
return 0;
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment