Apple M1 Microarchitecture Research by Dougall Johnson

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

UCVTF (vector, fixed-point, 8H from 8H)

Test 1: uops

Code:

  ucvtf v0.8h, v0.8h, #3
  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)031e3a3f4e51inst issue (52)~issue fp/simd (54)~dispatch fp/simd (57)huge thing fp/simd (5b)6061696d6edispatch 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)a6a7a8acc2cfd0d5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
100430372490612538451000100811503981601030543120308524147289511501000100030833084211001100031028654730116112629100030383038303830383038
100430372400612547251000100010003981601030183037303724143289510001000100030373037111001100000000730116112629100030383038303830383038
100430372500612547251000100010003981600530183037303724143289510001000100030373037111001100000000730116112629100030383038303830383038
100430372400612547251000100010003981601030183037303724143289510001000100030373037111001100000100735116112629100030383038303830383038
1004303724001662547251000100010003981600530183037303724143289510001000100030373037111001100000000735116112629100030383038303830383038
100430372330612547251000100010003981600530183037303724143289510001000100030373037111001100000000730116112629100030383038303830383038
100430372400612547251000100010003981600530183037303724143289510001000100030373037111001100000000735116112629100030383038303830383038
1004303723001052547251000100010003981601030183037303724143289510001000100030373037111001100000000730116112629100030383038303830383038
1004303724001702547251000100010003981600530183037303724143289510001000100030373037111001100000000735116112629100030383038303830383038
1004303723001032547251000100010003981600530183037303724143289510001000100030373037111001100000000735116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  ucvtf v0.8h, v0.8h, #3
  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)03191e1f3f4e51inst 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)9fa0a8accfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10204300372320001562954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
1020430037233000612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296650100001003003830038300383003830038
10204300372330006312954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
1020430037233090612954725101001001000010010150500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
10204300372320120612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010001071011611296330100001003003830038300383003830038
1020430037233000612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
10204300372330210612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
1020430037233000612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
102043003723304050612954725101001001000010010000500427716013001830037300372826432874510100202100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
1020430037232000612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296350100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)0308090b18191e1f3a3f4e51inst 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)9fa0a1a6a7a8a9acc2c5cfd5d6daddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10024300372380000000061295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000000064021602229629010000103003830038300383003830038
10024300372250000000066295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000000064021602229629010000103003830038300383003830038
10024300372250000090061295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000000064021602229629010000103003830038300383003830038
10024300372250000000061295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000000064021602229629010000103003830038300383003830038
100243003722500000000148295472510010101000010100005042771601300183003730037282863287671001020100002010000300373003711100211091010100001000000000064021602229629010000103003830038300383003830038
10024300702250000000061295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000000064021602229629010000103003830038300383003830038
10024300372250000000061295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000000064021602229629010000103003830038300383003830038
10024300372320000000061295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000000064021602229629010000103003830038300383003830038
100243003722500000000156295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000001000064021602229629010000103003830038300383003830133
10024300372250000000061295472510010121001610100005042771600300183008330037282868287671001020100002010000300373003721100211091010100001000000000064021602229629010000103008530086300383003830038

Test 3: throughput

Count: 8

Code:

  ucvtf v0.8h, v8.8h, #3
  ucvtf v1.8h, v8.8h, #3
  ucvtf v2.8h, v8.8h, #3
  ucvtf v3.8h, v8.8h, #3
  ucvtf v4.8h, v8.8h, #3
  ucvtf v5.8h, v8.8h, #3
  ucvtf v6.8h, v8.8h, #3
  ucvtf v7.8h, v8.8h, #3
  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)03090b18191e1f3f51inst 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)72scheduler 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)9fa0a1a6a7a8a9acc2c5branch mispredict (cb)cdcfd5d6dde0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8020420039155003000302580108100800081008002050064013202002020039200399977069990801202008003220080032200392003911802011009910010080000100022004308841115223289020285800001002019820354203032034720361
80204202491581036801528333213680403102806031048065050064590002030120353204011002903710147807642028034920280669204002040381802011009910010080000100240112140041115118016020036800001002004020040200402004020040
802042003915500001804942580108100800081008002050064013202002020039200399977069990801202008003220080032200392003911802011009910010080000100000020302115118016020036800001002004020040200402004020040
8020420039161000000302580108100800081008002050064013202002020039200399977069990801202008003220080032200392003911802011009910010080000100000000001115118016020036800001002004020040200402004020040
8020420039155000000302580108100800081008002050064013202002020039200399977069990801202008003220080032200392003911802011009910010080000100000000001115118016020036800001002004020040200402004020040
80204200391550000006952580108100800081008002050064013202002020039200399977069990801202008003220080032200392003911802011009910010080000100000000001115118016020036800001002004020040200402004020040
8020420039155000000302580108100800081008002050064013202002020039200399977069990801202008003220080032200392003911802011009910010080000100000000001115118016020036800001002004020040200402004020040
8020420039156000000862580108100800081008002050064013202002020039200399977069990801202008003220080032200392003911802011009910010080000100000000001115118016020036800001002004020040200402004020040
8020420039155000000302580108100800081008002050064013202002020039200399977069990801202008003220080032200392003911802011009910010080000100000000001115118016020036800001002004020040200402004020040
8020420039155000000302580108100800081008002050064013202002020039200399977069990801202008003220080032200392003911802011009910010080000100000000001115118016020036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)03191e3f51inst 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)5f60696d6edispatch 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)9fa0a8accdcfd0d5d6d9ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8002420050155004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100000502001160112003680000102004020040200402004020040
80024200391550037125800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100000502001160112003680000102004020040200402004020040
8002420039155004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100000502001160112003680000102004020040200402004020040
8002420039156004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100000502001160112003680000102004020040200402004020040
8002420039155004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100000502001160112003680000102004020040200402004020040
800242003915500193825800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100000502001160112003680000102004020040200402004020040
8002420039156004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100000502001160112003680000102004020040200402004020040
8002420039155004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100000502001160112003680000102004020040200402004020040
8002520039155004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100100502001160112003680000102004020040200402004020040
80024200391500640258001010800001080000506400000020020200392003910005310019800102080000208000020039200391180021109101080000100000502001160112003680000102004020040200402004020040