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

SCVTF (scalar, fixed-point, S from S)

Test 1: uops

Code:

  scvtf s0, s0, #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 uop (01)cycle (02)0318191e1f3f4e51schedule 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)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)f5f6f7f8fd
100430372300006125472510001000100039816003018303730372414328951000100010003037303711100110004073216222629100030383038303830383038
100430372300006125472510001000100039816003018303730372414328951000100010003037303711100110002073216222629100030383038303830383038
100430372200006125472510001000100039816003018303730372414328951000100010003037303711100110004073216222629100030383038303830383038
1004303723000061254725100010001000398160030183037303724143289510001000100030373037111001100083973216222629100030383038303830383038
100430372200006125472510001000100039816003018303730372414328951000100010003037303711100110002073216222629100030383038303830383038
100430372300006125472510001000100039816003018303730372414328951000100010003037303711100110003073216222629100030383038303830383038
100430372200006125472510001000100039816003018303730372414328951000100010003037303711100110000073216222629100030383038303830383038
100430372300306125472510001000100039816003018303730372414328951000100010003037303711100110000673216222629100030383038303830383038
100430372300006125472510001000100039816003018303730372414328951000100010003037303711100110006373216222629100030383038303830383038
1004303724000015625472510001000100039816013018303730372414328951000100010003037303711100110000073216222629100030383038303830383038

Test 2: Latency 1->2

Code:

  scvtf s0, s0, #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 uop (01)cycle (02)033f4e51schedule 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)accdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
102043003722561295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038
102043003722561295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038
1020430037225128295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001001007101161129633100001003003830038300383003830038
102043003722561295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038
102043003722561295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038
102043003722561295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001001007101161129633100001003003830038300383003830038
102043003722561295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038
102043003722561295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001001007101161129633100001003003830038300383003830038
1020430037281217295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001001007101161129633100001003003830038300383003830038
1020430037225943295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038

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)18191e1f3f4e51schedule 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 load (98)inst simd alu (9a)9fl1d tlb access (a0)l1d tlb miss (a1)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
100243003722400001201032954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910100100001000040606402162229629010000103003830038300383003830038
100243003722500001206129547251001010100001010000504277160130018300373003728286328767100102010000201000030037300371110021109101001000010000106287451133430131310000103045530651306073064330686
1002430415246101313184811449013294392421011418100961311800894292063030594305923050928336612899111815261196224121473065330651141100211091010010000102441236692081451363330094510000103065030654306843065230606
1002430037232007017161232396629457243101021410096121195060429338403045030698306402833159289861136528113242812061306953063810110021109101001000010001003906506404942429940710000103055630641305573055530556
10024305072371112131728105691122943026610111191010414113509442948460304503073630499283395729007121182210000201000030037300371110021109101001000010000106285031283429788210000103036730554306053060330511
10024303662370100601032954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910100100001000010306402162229629010000103003830038300383003830038
10024300372250000120103295472510010101000010100005042771601300183003730037282863287671001020100002010000300373003711100211091010010000100001012606402162229629010000103003830038300383003830038
10024300372240000120612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910100100001000080606402162229629010000103003830038300383003830038
1002430037225000012010329547251001010100001010000504277160130018300373003728286328767100102010000201016130037300371110021109101001000010000101206402162229629010000103003830038300383003830038
10024300372250000006129547251001010100001010000504277160130018300373003728286328767100102010000201000030037300371110021109101001000010000109006402162229629010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  scvtf s0, s8, #3
  scvtf s1, s8, #3
  scvtf s2, s8, #3
  scvtf s3, s8, #3
  scvtf s4, s8, #3
  scvtf s5, s8, #3
  scvtf s6, s8, #3
  scvtf s7, s8, #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 uop (01)cycle (02)0318191e1f3f51schedule 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 miss (a1)ld unit uop (a6)l1d cache writeback (a8)a9acbranch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
80204200601510000512580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151182161120036800001002004020040200402014820040
80204200391500000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000030011151181161120036800001002004020040200402004020040
802042003918800001982580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151181161120036800001002004020040200402004020040
80204200391500000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151181161220036800001002004020040200402004020040
80204200391500000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151181161120036800001002004020040200402004020040
80204200391500000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151181161120036800001002004020040200402004020040
80204200391500000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000020011151181161120036800001002004020040200402004020040
80204200391500000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151181161120036800001002004020040200402004020040
80204200391500000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151181161120036800001002004020040200402004020040
80204200391500000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151181161120036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)03mmu table walk data (08)0918191e1f3f51schedule 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)st unit uop (a7)l1d cache writeback (a8)accfd5map dispatch bubble (d6)dadbddfetch restart (de)e0eb? simd retires (ee)? int retires (ef)f5f6f7f8fd
8002420039150000012082258001010800001080000506400001200202003920039999631001980010208000020800002003920039118002110910108000010000105020316003220036080000102004020040200402004020040
8002420039150000012082258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010000135020216003220036080000102004020040200402004020040
800242003915000000082258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010000235020316003320036080000102004020040200402004020040
8002420039150000012082258001010800001080000506400001200202003920039999631001980010208000020800002003920039118002110910108000010000135020416003320036080000102004020040200402004020040
8002420039150000012082258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010000195020316003320036080000102004020040200402004020040
8002420039150000012082258001010800001080000506400000200202003920039999631001980010208000020801042003920100118002110910108000010000235020216003420036080000102004020040200402004020040
8002420039150000012082258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010000135020216003320036080000102004020040200402004020040
8002420039150000012082258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010000105020316002320036080000102004020040200402004020040
8002420039150000012082258001010800001080000506400001200202003920039999631001980010208000020800002003920039118002110910108000010000305020316003220036080000102004020040200402004020040
8002420039150000012082258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010000005020216002320036080000102004020040200402004020145