Apple M1 Microarchitecture Research by Dougall Johnson

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

FCVTZU (scalar, fixed-point, H to H)

Test 1: uops

Code:

  fcvtzu h0, h0, #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)03080b18191e1f3a3f4e51inst 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)a0a1a6a7a8a9acc2cfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
1004303724000000017925472510001000100039816003018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
100430372400000006125472510001000100039816003018303730372414328951000100010003037303711100110000000100073116112629100030383038303830383038
100430372300000006125472510001000100039816003018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
1004303724000012006125472510001000100039816003018303730372414328951000100010003037303711100110000000203073116112629100030383038303830383038
1004303724000000019225472510001000100039816003018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
100430372300000006125472510001000100039816013018303730372414328951000100010003037303711100110000000003073116112629100030383038303830383038
1004303723000000010325472510001000100039816003018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
100430372300000006125472510001000100039816003018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
1004303724000000037725472510001000100039816003018303730372414328951000100010003037303711100110000000100073116112629100030383038303830383038
100430372300000006125472510001000100039816003018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtzu h0, h0, #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)030b1e3f4e51inst 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)9fa8dtlb miss (c1)cfd5d6ddinst fetch restart (de)e0? int output thing (e9)ec? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
102043003723200612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000710116112963300100001003003830038300383003830038
102043003723300612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000710116112963300100001003003830038300383003830038
102043003723200612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000710116112963300100001003003830038300383003830038
102043003723200612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010010710116112963300100001003003830038300383003830038
1020430037233005362954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000710116112963300100001003003830038300383003830038
102043003723200612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000710116112963300100001003003830038300383003830038
1020430037233012612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000710116112963300100001003003830038300383003830038
102043003723300822954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300372110201100991001001000010000710116112963300100001003003830038300383003830038
102043003723200612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000710116102963300100001003003830038300383003830038
102043003723300612954725101001001000010010000500427716013001830084301322826432874510100200100002001000030037300371110201100991001001000010000710116112963300100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)03191e3f4e51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)~dispatch ld/st (58)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)9fa6a8a9accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10024300372320061295472510010101000010100000504277160130018300373003728286328767100102010652201000030037300371110021109101010000100000640216222962910000103003830038300383003830038
10024300372330061295472510010101000010100000504277160030018300373003728304328767100102010000201000030037300371110021109101010000100000640216222962910000103003830038300383003830038
10024300372330061295472510010101000010100000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100006640216222962910000103003830038300383003830038
10024300372330061295472510010101000010100000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000640216222962910000103003830038300383003830038
10024300372330061295472510010101000010100000504277160130090300373003728286328767100102010000201000030037300377110021109101010000100200640216222962910000103003830038300383003830038
10024300372331361295472510010101000010100000504277160030018300373003728286328767100102010649201000030037300372110021109101010000100000640216222962910000103003830038300383003830038
10024300372330061295472510010101000010100000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000640216222962910000103003830038300383003830038
100243003723200673295472510010101000010100000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000640216222962910000103003830038300383003830038
100243003723300251295472510010101000010100000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000640216222962910000103003830038300383003830038
10024300372330061295472510010101000010100000504277160030018300373003728286328767100102010000201000030037300371110021109101010000101000640216222962910000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtzu h0, h8, #3
  fcvtzu h1, h8, #3
  fcvtzu h2, h8, #3
  fcvtzu h3, h8, #3
  fcvtzu h4, h8, #3
  fcvtzu h5, h8, #3
  fcvtzu h6, h8, #3
  fcvtzu h7, h8, #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)030b1e3f51inst 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)9fa0a8acc2c5branch mispredict (cb)cdcfd5d6e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
802042005815500302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511841620036800001002004020040200402004020040
802042003915500302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801620036800001002004020040200402004020040
802042003915500302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801620036800001002004020040200402004020040
802042003915500302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801620036800001002004020040200402004020040
802042003915500582580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000100111511801620036800001002004020040200402004020040
8020420039155012512580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801620036800001002004020040200402004020040
802042003915500302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801620036800001002004020040200402004020040
802042003915500302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801620036800001002004020040200402004020040
802042003915600302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000100111511801620036800001002004020040200402004020040
802042003915500302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801620036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)0318191e3f51inst 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)9fa1a8accfd0icache miss (d3)d5d6daddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
800242005115500244025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100005020003160112003680000102004020040200402004020040
80024200391550004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100005020001160112003680000102004020040200402004020040
80024200391610004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100005020003160112003680000102004020040200402004020040
80024200391560004025800101080000108000050640000012002020039200399996310019800102080000208000020039200391180021109101080000100005020001160112003680000102004020040200402004020040
800242003915500051525800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100005020001160112003680000102004020040200402004020040
80024200391550004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100005020001160112003680000102004020040200402004020040
80024200391550004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100005020301160112003680000102004020040200402004020040
80024200391550004025800101080000108000050640000002014220039200399996310019800102080000208000020039200391180021109101080000100005020311161112003680000102004020040200402004020040
800242003915500334025800101080000108000050640000102002020039200399996310019800102080000208000020039200391180021109101080000100005020001160112003680000102004020040200402004020040
80024200391550004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100005020001160222003680000102004020040200402004020040