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

FCVTN (vector, 4S)

Test 1: uops

Code:

  fcvtn v0.4h, v0.4s
  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)03mmu table walk data (08)0918191e1f3f4e51schedule 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)l1d cache writeback (a8)a9acc2cfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)f5f6f7f8fd
1004303724000000612547251000100010003981601301830373037241432895100010001000303730371110011000000073116112629100030383038303830383038
10043037230000003692547251000100010003981600301830373037241432895100010001000303730371110011000000073116112629100030383038303830383038
1004303723000100842547251000100010003981600301830373037241432895100010001000303730371110011000000073116112629100030383038303830383038
1004303723000000612547251000100010003981600301830373037241432895100010001000303730371110011000100073116112629100030383038303830383038
1004303723000000612547251000100010003981600301830373037241432895100010001000303730371110011000000073116112629100030383038303830383038
10043037230000003482547251000100010003981600301830373037241432895100010001000303730371110011000000073116112629100030383038303830383038
10043037220000001622547251000100010003981600301830373037241432895100010001000303730371110011000000073116112629100030383038303830383038
10043037220000001442547251000100010003981600301830373037241432895100010001000303730371110011000000073116112629100030383038303830383038
1004303722000000612547251000100010003981600301830373037241432895100010001000303730371110011000000073116112629100030383038303830383038
10043037230000001242547251000100010003981600301830373037241432895100010001000303730371110011000000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtn v0.4h, v0.4s
  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)03mmu table walk data (08)l2 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)60696b6d6emap 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)accdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
10204300372330006129547251010010010000100100005004277160130018030037300372826432874510100200100002001000030037300371110201100991001001000010000071021622296330100001003003830038300383003830038
10204300372330006129547251010010010000100100005004277160030018030037300372826432874510100200100002001000030037300371110201100991001001000010000071021622296330100001003003830038300383003830038
10204300372320012199629547251010010010000100100005004277160130018030037300372826432874510100200100002001000030037300371110201100991001001000010000071021622296330100001003003830038300383003830038
10204300372321006129547251010010010000100100005004277160130018030037300372826432874510100200100002001000030037300371110201100991001001000010000071021622296330100001003003830038300383003830038
10204300372330006129547251010010010000100100005004277160130018030037300372826432874510100200100002001000030037300371110201100991001001000010000071021622296330100001003003830038300383003830038
102043003724100128929547251010010010000100100005004277160130018030037300372826432874510100200100002001000030037300371110201100991001001000010000071021622296330100001003003830038300383003830038
10204300372320006129547251010010010000100100005004277160030018030037300372826432874510100200100002001000030037300371110201100991001001000010000071021622296330100001003003830038300383003830038
10204300372320006129547251010010010000100100005004277160130018030037300372826432874510100200100002001000030037300371110201100991001001000010000071021622296330100001003003830038300383003830038
10204300372330006129547251010010010000100100005004277160130018030037300372826432874510100200100002001000030037300371110201100991001001000010000071021622296330100001003003830038300383003830038
10204300372330006129547251010010010000100100005004277160030018030037300372826432874510100200100002001000030037300371110201100991001001000010010071021622296330100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire uop (01)cycle (02)03mmu table walk data (08)l2 tlb miss data (0b)0e18191e1f3f4e5051schedule 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 tlb miss (a1)ld unit uop (a6)st unit uop (a7)l1d cache writeback (a8)a9acc2cfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
100243003723300000006129547025100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000000006402162229629010000103003830038300383003830038
100243003723200000006129547025100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000022306402162229667010000103003830038300383003830038
100243003723300000006129547025100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000000306402162229629010000103003830038300383003830038
1002430037233000000010329547025100101010000101000050427716003001830037300372829162876710163201000024100003003730037111002110910101000010000000006612162229629010000103003830038300383003830038
1002430037233000000015629547025100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000000306402162229629010000103003830038300383003830038
100243003723300000006129547025100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000000006402162229629010000103003830038300383003830038
100243003724600000006129547025100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000000006402162229629010000103003830038301323013430038
100243003723300000006129547025100101010000101000050427716003001830037300372828832876710010201016720100003008430084111002110910101000010022000006402162229629010000103003830038300383003830038
100243003723200000006129547025100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000000006402162229629010000103003830038300383003830038
10024300372330000000272629547025100101010000101000050427716003001830037300372828632876710010201065020100003003730037111002110910101000010000002006402162229629010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtn v0.4h, v8.4s
  fcvtn v1.4h, v8.4s
  fcvtn v2.4h, v8.4s
  fcvtn v3.4h, v8.4s
  fcvtn v4.4h, v8.4s
  fcvtn v5.4h, v8.4s
  fcvtn v6.4h, v8.4s
  fcvtn v7.4h, v8.4s
  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)031e3f51schedule 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)acbranch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfl1i cache miss demand (d3)d5map dispatch bubble (d6)dde0? simd retires (ee)? int retires (ef)f5f6f7f8fd
80204200391550302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000011151180016020036800001002004020040200402004020040
80204200391550302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000011151180016020036800001002004020040200402004020040
80204200391550302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000011151180016020036800001002004020040200402004020040
80204200391550302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000011151180016020036800001002004020040200402004020040
80204200391550302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000011151180016020036800001002004020040200402004020040
80204200391550302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000011151180016020036800001002004020040200402004020040
80204200391560302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000011151180016020036800001002004020040200402004020040
802042003916003072580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000011151180016020036800001002004020040200402004020040
80204200391550302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000011151180016020036800001002004020040200402004020040
80204200391550302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000011151180116020036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)03l2 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)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)l1d cache writeback (a8)a9acc2cfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
800242005115600000402580010108000010800005064000002002020039200399996281001980010208000020800002003920039118002110910108000010000305020171616162003680000102004020040200402004020040
8002420039156000004025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000000502016166162003680000102004020040200402004020040
8002420039156000004025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000000502061617162003680000102004020040200402004020040
800242003915500000402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100000050206166162003680000102004020040200402004020040
800242003915601100402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100000050207161662003680000102004020040200402004020040
8002420039156000004025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000000502016166162003680000102004020040200402004020040
8002420039166000004025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000000502061616162003680000102004020040200402004020040
800242003915500000402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100000050206161662003680000102004020040200402004020040
8002420039155000008225800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000000502016166162003680000102004020040200402004020040
8002420039155000120402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100000050207166162003680000102004020040200402004020040