Apple M1 Microarchitecture Research by Dougall Johnson

Firestorm: Overview | Base Instructions | SIMD and FP Instructions
Icestorm:  Overview | Base Instructions | SIMD and FP Instructions

FCVTNS (scalar, S to S)

Test 1: uops

Code:

  fcvtns s0, s0
  movi v0.16b, 1
  movi v1.16b, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 1.000

Integer unit issues: 0.000

Load/store unit issues: 0.000

SIMD/FP unit issues: 1.000

retire (01)cycle (02)031e3f4e51inst issue (52)~issue fp/simd (54)~dispatch fp/simd (57)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op fp/simd (7e)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst neon or fp (9a)a8acc2cfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
1004303724061254725100010001000398160130183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
10043037240612547251000100010003981601301830373037241432895100010001000303730371110011000051473116112629100030383038303830383038
1004303723061254725100010001000398160130183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303723061254725100010001000398160130183037303724143289510001000100030373037111001100010073116112629100030383038303830383038
1004303723661254725100010001000398160130183037303724143289510001000100030373037111001100003073116112629100030383038303830383038
1004303723061254725100010001000398160130183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303725061254725100010001000398160130183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303724061254725100010001000398160130183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303724061254725100010001000398160130183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303723061254725100010001000398160130183037303724143289510001000100030373037111001100000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtns s0, s0
  movi v0.16b, 1
  movi v1.16b, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)030818191e3f4e51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa1a8acc2cfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
102043003723300002122954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
102043003723300001502954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010001007101161129633100001003003830038300383003830038
10204300372320000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
10204300372330000612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
10204300372330000612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
102043003723300001872954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
10204300372330000962954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
102043003723200004812954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
10204300372330000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
10204300372330000612950925101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)0308191e1f3a3f4e51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa0a1a8acc2cfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1002430037224000001662954725100101010000101000050427716013001830037300372828632876710010201017920100003003730037111002110910101000010000006402162229629010000103003830038300383003830038
100243003722500000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000006402162329629010000103003830038300383003830038
100243003722500000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000006402162229629010000103003830038300383003830038
1002430037225000001662954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000006402162329629010000103003830038300383003830038
100243003722500000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000006402162329629010000103003830038300383003830038
100243003722500000612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000006402162329629010000103003830038300383003830038
100243003722500000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000006402162229629010000103003830038300383003830038
100243003722500000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000006402162329629010000103003830038300383003830038
100243003722500000612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000006402162329629010000103003830038300383003830038
100243003728400000612954744100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000006402162229629010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtns s0, s8
  fcvtns s1, s8
  fcvtns s2, s8
  fcvtns s3, s8
  fcvtns s4, s8
  fcvtns s5, s8
  fcvtns s6, s8
  fcvtns s7, s8
  movi v8.16b, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.2505

retire (01)cycle (02)031e3f51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)60696b6d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa6a8acc5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0ea? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80204200391560302580108100800081008002050064013212002002003920039997769990801202008003220080032200392003911802011009910010080000100010111511801600200360800001002004020040200402004020040
80204200391560302580108100800081008002050064013202002002003920039997769990801202008003220080032200392003911802011009910010080000100000111511801600200360800001002004020040200402004020040
80204200391550302580108100800081008002050064013212002002003920039997769990801202008003220080032200392003911802011009910010080000100000111511801600200360800001002004020040200402004020040
80204200391550302580108100800081008002050064013212002002003920039997769990801202008003220080032200392003911802011009910010080000100000111511801600200360800001002004020040200402004020040
80204200391550302580108100800081008002050064013202002002003920039997769990801202008003220080032200392003911802011009910010080000100000111511811600200360800001002004020040200942004020090
80204201021550302580108100800081008002050064013212002002003920039997769990801202008003220080032200392003911802011009910010080000100000111511801600200360800001002004020040200402004020040
80204200391550302580108100800081008002050064013202002002003920039997769990801202008003220080032200392003911802011009910010080000100010111511801600200360800001002004020040200402004020040
80204200391550302580108100800081008002050064013212002002003920039997769990801202008003220080032200392003911802011009910010080000100000111511801600200360800001002004020040200402004020040
80204200391560302580108100800081008002050064013212002002003920039997769990801202008003220080032200392003911802011009910010080000100016111511801600200360800001002004020040200402004020040
80204200391560582580108100800081008002050064013212002002003920039997769990801202008003220080032200392003911802011009910010080000100010111511801600200360800001002004020040200402004020040

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.2505

retire (01)cycle (02)0304091e3f51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)6061696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa8accfd0d2icache miss (d3)itlb miss (d4)d5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80024200391551108625800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100050385000248123232003680000102004020040200402004020040
8002420039155111212925800101080000108000050640000102002020039200399996310019800102080000208000020039200391180021109101080000100050210001133124222003680000102004020040200402004020040
800242003915511078225800101080000108000050640000052002020039200399996310019800102080000208000020039200391180021109101080000100050210001223022132003680000102004020040200402004020040
80024200391551108625800101080000108000050640000052002020039200399996310019800102080000208000020039200391180021109101080000100050210001223023182003680000102004020040200402004020040
80024200391551108625800101080000108012450640000002002020039200399996310019800102080000208000020039200391180021109101080000100050210001223123142003680000102004020040200402004020040
80024200391551108625800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100050210001183118222003680000102004020040200402004020040
80024200391551108625800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100050210101194617232003680000102004020040200402004020040
80024200391551108625800101080000108000050640000202002020039200399996310019800102080000208000020039200391180021109101080000101050200000331624152003680000102004020040200402004020040
80024200391550004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100050200000291623132003680000102004020040200402004020040
800242003915500124025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100050200000321622232003680000102004020040200402004020040