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 (D to S)

Test 1: uops

Code:

  fcvt s0, d0
  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)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)f5f6f7f8fd
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110001673116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723156125472510001000100039816013022303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723061254725100010001000398160130183037303724143289510001000100030373037111001100013073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372366125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372206125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvt s0, d0
  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)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)9fst unit uop (a7)l1d cache writeback (a8)acbranch cond mispred nonspec (c5)cfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
102043003722500612954725101001001000010010000500427716013001830037300372826432874510100200100002001017430037300371110201100991001001000010000007101161129633100001003003830038300383003830038
102043003722500612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
1020430037224006129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100002107101161129633100001003003830038300383003830038
102043003722500612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
102043003722500612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
102043003722500612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
102043003722500612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038
102043003722500612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000288607101161129633100001003003830038300383003830038
102043003722500612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300841110201100991001001000010000007101161129633100001003003830038300383003830038
102043003722500612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000007101161129633100001003003830038300383003830038

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)18191e1f3a3f4e51schedule 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)l1d cache writeback (a8)a9acc2branch mispred nonspec (cb)cfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
10024300372250000000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000000006404163329629010000103003830038300383003830038
100243003722500000007262954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000100006403243329629010000103003830038300383003830038
100243003722500000006129547251001010100001010000504277160130018300373003728286328767100102010000201000030131300371110021109101010000104420019585207875724529880210000103012230357303223036730358
10024302712270026933616052502948413310072141005616110508242852721302343041530369283163328899110662211140201132230368300848110021109101010000100001020648007944724429881310000103036930371303703036230368
1002430368227017793361605772294841681007614100641311200824287976130306304633041428315382892811212221147124114593046330460101100211091010100001040212250836068541015529980210000103046330466304173045230319
100243041722811821068704152072946619010086121006420112007742890261303063045530452283173728935113622011174221146930463304159110021109101010000100201225280208324546329953410000103046230464304603046630464
1002430411227019979261607872954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000000006403163329629010000103003830038300383003830038
10024300372250000000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000000006403163329629010000103003830038300383003830038
10024300372250000000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000000006403163329629010000103003830085300383003830038
10024300372250000000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000000006403163329629010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvt s0, d8
  fcvt s1, d8
  fcvt s2, d8
  fcvt s3, d8
  fcvt s4, d8
  fcvt s5, d8
  fcvt s6, d8
  fcvt s7, d8
  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)1e3f51schedule 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)simd prf full (72)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)acc2branch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
80204200611500030258010810080008100800205006401321200202003920039997706999080120200800322008003220039200391180201100991001008000010003011151181160020036800001002004020040200402004020040
802042003915000177258010810080008100800205006401321200202003920039997706999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391500093258010810080008100800205006401321200202003920039997706999080120200800322008003220039200391180201100991001008000010003011151180160020036800001002014020040200402004020040
80204200391500030258010810080008100800205006401321200202003920039997706999080120200800322008003220039200391180201100991001008000010001888011151180160020036800001002004020040200402004020040
802042003915000328258010810080008100800205006401321200202003920039997706999080120200800322008003220039200391180201100991001008000010000211151180160020036800001002004020040200402004020040
80204200391500030258010810080008100801305006401321200202003920039997706999080120200800322008003220039200391180201100991001008000010000011151180161020036800001002004020040200402004020040
80204200391500030258010810080008100800205006401321200202003920039997706999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391500030258010810080008100800205006401321200202003920039997706999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391500030258010810080008100800205006401321200202003920039997706999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391500095258010810080008100800205006401321200202003920039997706999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040

1000 unrolls and 10 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)6061696b6d6emap 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)9faccfd0d2l1i tlb miss demand (d4)d5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
800242003915012402580010108000010800005064000000200200200392003999963100198001020800002080000200392003911800211091010800001005020003141612102003680000102004020040200402004020040
80024200391500218258001010800001080000506400000020020020039200399996310019800102080000208000020039200391180021109101080000100502000110161272003680000102004020040200402004020040
8002420039150040258001010800001080000506400000020020020039200399996310019800102080000208000020039200391180021109101080000100502000191612122003680000102004020040200402004020040
8002420039150063258001010800001080000506400000020020020039200399996310019800102080000208000020039200391180021109101080000100502000281611112003680000102004020040200402004020040
80024200391500402580010108000010800005064000000200200200392003999963100198001020800002080000200392003911800211091010800001005020030161611122003680000102004020040200402004020040
80024200391500632580010108000010800005064000005200200200392003999963100198001020800002080000200392003911800211091010800001005020533122511122003680000102004020040200402019320040
800242003915201277258001010800001080000506400000520020020039200399996310019800102080000208000020039200391180021109101080000100502000291611112003680000102004020040200402004020040
80024200391501240258001010800001080000506400000520020020039200399996310019800102080000208000020039200391180021109101080000100502003161612122003680000102004020040200402004020040
80024200391500126258001010800001080000506400000020020020039200399996310019800102080000208000020039200391180021109101080000100502050061610112003680000102004020040200402004020040
8002420039150040258001010800001080000506400000020020020039200391001431001980010208000020800002003920039118002110910108000010350200018161072003680000102004020040200402004020040