Apple Microarchitecture Research by Dougall Johnson

M1/A14 P-core (Firestorm): Overview | Base Instructions | SIMD and FP Instructions
M1/A14 E-core (Icestorm):  Overview | Base Instructions | SIMD and FP Instructions

FCVT (S to H)

Test 1: uops

Code:

  fcvt h0, 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 uop (01)cycle (02)031e3f4e51schedule uop (52)schedule simd uop (54)dispatch simd uop (57)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map simd uop (7e)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst simd alu (9a)acc2cfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)f5f6f7f8fd
100430372206125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723084254725100010001000398160130183037303724143289510001000100030373037111001100042073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372206125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372206125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvt h0, 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 uop (01)cycle (02)031e3f4e51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fld unit uop (a6)st unit uop (a7)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
1020430037225156612954725101001001000010010000500427716003001830037300372827632874510100200100002001000030037300371110201100991001001000010000128707101161129633100001003003830038300383003830038
10204300372240612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
10204300372250612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
10204300372250612954725101001001000010010000500427716003001830084300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
10204300372250612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
10204300372250612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000028017101161129633100001003003830038300383003830038
10204300372250612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
102043003722530612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000107101161129633100001003003830038300383003830038
10204300372250612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
10204300372250612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire uop (01)cycle (02)03l2 tlb miss data (0b)1e3f4e51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fl1d tlb access (a0)l1d cache writeback (a8)accdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
10024300372250876129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000640316222962910000103003830038300383003830038
10024300372250248229547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000640316222962910000103003830038300383003830038
10024300372250246129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000640216222962910000103003830038300383003830038
1002430037225006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000640216222962910000103003830038300383003830038
10024300372250276129547251001010100001010000504277160130018300373003728286328767100102010000201000030037300371110021109101010000100000640216222970110000103003830038300383003830038
10024300372250366129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000640216222962910000103003830038300383003830038
10024300372250216129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000640224222962910000103003830038300383003830038
100243003722503396129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000640216222962910000103003830038300383003830038
10024300372250246129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000640216222962910000103003830038300383003830038
10024300372250246129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000640216222962910000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvt h0, s8
  fcvt h1, s8
  fcvt h2, s8
  fcvt h3, s8
  fcvt h4, s8
  fcvt h5, s8
  fcvt h6, s8
  fcvt h7, 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 uop (01)cycle (02)03mmu table walk data (08)09l2 tlb miss data (0b)18191e1f3f51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fld unit uop (a6)st unit uop (a7)l1d cache writeback (a8)a9acc2branch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
80204200581500000000302580108100800081008002050064013220020200392003999776999080120200801422008003220039200391180201100991001008000010000000011151181161120036800001002004020040200402004020040
80204200391500000000302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000000011151181161120036800001002004020040200402004020040
802042003915000000003025801081008000810080020500640132200202003920039997715999080120200800322008003220039200391180201100991001008000010000090011151181161120036800001002004020040200402004020040
802042003915000000150302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000100011151181161120036800001002004020040200402004020040
802042003915000000270302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000000011151181161120036800001002004020040200402004020040
80204200391500000030302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000000011151181162120036800001002004020040200402004020040
80204200391500000000302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000000011151181161120036800001002004020040200402004020040
80204200391500000000302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000003011151181161120036800001002004020040200402004020040
80204200391500000000302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000000011151181161120036800001002004020040200402004020040
80204200391500000000302580108100800081008002050064013220020200392009999776999080120200800322008003220039200391180201100991001008000010000000011151181161120036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)031e3a3f51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fl1d cache writeback (a8)accfd2l1i cache miss demand (d3)d5map dispatch bubble (d6)d9dadbddfetch restart (de)e0eaeb? simd retires (ee)? int retires (ef)f5f6f7f8fd
800242005015000402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100050200021600011200360080000102004020040200402004020040
800242003915000402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100050200011600011200360080000102004020040200402004020040
800242003915000402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100050200011600011200360080000102004020040200402004020040
800242003915000402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100050200011600011200360080000102004020040200402004020040
800242011215100402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100050200011600011200360080000102004020040200402004020040
800242003915000402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100050200011600011200360080000102004020040200402004020040
800242003915000402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100050200011600011200360080000102004020040200402004020040
800242003915000402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000101050200011600011200360080000102004020040200402004020040
800242003915030402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100050200011600011200360080000102004020040200402004020040
800242003915000402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100050200011600011200360080000102004020040200402004020040